The article examines the tectonic structure of the South Caspian Basin and proposes a more accurate position of its western pre-Cenozoic tectonic boundary. The structural reconstruction of the Cenozoic sedimentary cover presented in this study is based on basin analysis supported by numerical modeling technologies. The modeling results reveal a relatively high density and, at the same time, a pronounced spatial heterogeneity in the distribution of fold dislocations from the Mesozoic basement to the surface, particularly in the vicinity of mud volcano structures. The dominant mechanism of folding is associated with volume redistribution of low-viscosity, clay-rich Maykop horizons, which are prone to plastic flow under the load of the overlying thick Upper Miocene–Pliocene–Pleistocene succession. In the marginal parts of the basin, as well as above large, buried, and presumably weakly mobile structures within the inner basin, the formation and zonal arrangement of fold and fault dislocations are additionally controlled by geodynamic conditions, determined by external compressional, extensional, and shear stress regimes. The fold architecture of the Cenozoic succession – governing the presence and quality of hydrocarbon traps and fluid supply pathways – combined with favorable sedimentary-paleogeographic, thermodynamic, and other geological factors, underpins the high hydrocarbon potential of the entire South Caspian Basin.

Keywords: South Caspian Basin; South Caspian Depression; tectonic boundaries; stress fields; folding; diapirism; mud volcanism; faults; oil and gas productivity.

Date submitted: 06.02.2025     Date accepted: 13.06.2025

References

1. Popov, S. V., Shcherba, I. G., Stolyarov, A. S., et al. (2003). Lithological-paleogeographic maps of Paratethys. Moscow: Paleontological Institute RAS. Frankfurt am Main: Forschungsinstitut und Naturmuseum Senkenberg, BRD.
2. Ryan, W. B. F., Carbotte, S. M., Coplan, J. O., et al. (2009). Global multi-resolution topography synthesis. Geochemistry Geophysics Geosystems, 10(3), 1-9.
3. Jackson, J. A, McKenzie, D. P. (1984). Active tectonics of the Alpine-Himalayan belt between western Turkey and Pakistan. Geophysical Journal International, 77(1), 185–264.
4. Zonnenshain, L. P, Picho, L. (1986). Deep basins of the Black Sea and Caspian Sea as remnants of Mesozoic back-arc basins. Tectonophysics, 123, 181-211.
5. Rebat, S., Philip, H., Dorbath, L., et al. (1993). Active tectonics in the Lesser Caucasus: coexistence of compressive and extensional structures. Tectonics, 12(5), 1089-1114.
6. Jackson, J. A, Haines, A. J, Holt, W. E. (1995). The accommodation of Arabia-Eurasia plate convergence in Iran. Journal of Geophysical Research, 100, 205–219.
7. Mangino, S., Priestley, K. (1998). The crustal structure of the southern Caspian region. Geophysical Journal International, 133(3), 630–648.
8. Axen, G. J, Lam, P. S, Grove, M., Stockli, D. F. (2001). Exhumation of the west-central Alborz Mountains, Iran, Caspian subsidence, and collision-related tectonics. Geology, 29, 559–562.
9. Allen, N. B, Jones, S., Ismail-Zadeh, A., et al. (2002). Onset of subduction as the cause of rapid Pliocene-Quaternary subsidence in the South Caspian Basin. Geology, 30(9), 775–778.
10. Allen, M. B, Vincent, S. J, Alsop, G. I, et al. (2003). Late Cenozoic deformation in the South Caspian region: effects of a rigid basement block within a collision zone. Tectonophysics, 366, 223 – 239.
11. Jackson, J. A, Priestley, E., Allen, M., Berberian, M. (2002). Active tectonics of the South Caspian Basin. Geophysical Journal International, 148, 214–245.
12. Vernant, P., Nilforoushan, F., Che´ry, J., et al. (2004). Deciphering oblique shortening of central Alborz in Iran using geodetic data. Earth and Planetary Science, 223, 177-185.
13. Golonka, J. (2004). Plate tectonic evolution of the southern margin of Eurasia in the Mesozoic and Cenozoic, Tectonophysics, 381, 235– 273.
14. Golonka, J. (2007). Geodynamic evolution of the South Caspian Basin /In: P. O. Yilmaz and G. H. Isaksen (Eds.) Oil and gas of the Greater Caspian area. AAPG Studies in Geology, 55, 17–41.
15. Mamedov, P. Z. (2006) Peculiarities of the Earth's crust of the South Caspian Basin in light of new geophysical data. News of the Azerbaijan National Academy of Sciences. Earth Sciences, 3, 36-48.
16. Mamedov, P. Z. (2010) Modern architecture of the South Caspian megabasin is the result of multi-stage evolution of the lithosphere in the central segment of the Alpine-Himalayan mobile belt. News of the Azerbaijan National Academy of Sciences. Earth Sciences, 4, 46-72.
17. Manafi, M., Arian, M., Raeesi, S. H. T., Solgi, A. (2013). Tethys subduction history in Caucasus region. Open Journal of Geology, 3, 222-232.
18. Sharkov, E., Lebedev, V., Chugaev, A., et al. (2015). The Caucasian-Arabian segment of the Alpine-Himalayan collisional belt: Geology, volcanism and neotectonics. Geoscience Frontiers V, 6(4), 513-522.
19. Kadirov, F. A., Floyd, M., Reilinger, R., et al. (2015). Active geodynamics of the Caucasus region: implications for earthquake hazards in Azerbaijan. Proceedings of Azerbaijan National Academy of Sciences. The Sciences of Earth, 3, 3–17.
20. Lukk, A. A., Shevchenko, V. I. (2019). Seismicity, tectonics and GPS-geodynamics of the Caucasus. Physics of the Earth, 4, 99–123.
21. Klenova, M. V., Solovyov, V. F., Aleksina, I. A., et al. (1962). Geological structure of the underwater slope of the Caspian Sea. Moscow: Academy of Sciences of the USSR.
22. Khain, V. E., Popkov, V. I., Yudin, V. V., Chekhovich, P. A. (2006). The main stages of development of the Black Sea-Caspian Region. Ecological Bulletin of Scientific Centers of the Black Sea Economic Cooperation. Krasnodar, 2, 98–106.
23. Yusubov, N. (2023). Traces of paleogeodynamic processes in the zone junctions of the Middle and Lower Kura depressions. Geofizicheskiy Zhurnal, 45(5), 119—125.
24. Abdullayev, N. R., Riley, G. W., Bowman, A. P. (2012). Regional controls on lacustrine sandstone reservoirs: The Pliocene of the South Caspian Basin /In: O. W. Baganz, Y. Bartov, K. Bohacs, and D. Nummedal (Eds.). Lacustrine sandstone reservoirs and hydrocarbon systems. AAPG Memoir, 95, 71–98.
25. Yusubov, N. P., Guliyev, I. S., Soto, J. I. (2024). Structure and formation of mud volcanoes in the South Caspian Basin according to seismic data. Interpretation, 12(4), 105–118.
26. Abdullayev, N. R., Guliyev, I. S., Kadirov, F. A., et al. (2024). Novel interpretation of the crustal structure and hydrocarbon evolution within the South Caspian and Kura sedimentary basins, Azerbaijan. Geofizychnyi Zhurnal, 46(3), 146-161.
27. Guliyev, I. S., Abdullayev, N. R., Huseynova, Sh. M. (2020). Distribution and volume of rocks in sedimentary basins – unusual case of the South Caspian basin. SOCAR Proceedings, 3, 4-10.
28. Kerimov, K. M., Huseynov, A. N., Gadzhiev, F. M., et al. (2002). Map of tectonic zoning of oil and gas regions of Azerbaijan. Baku: Cartography Factory.
29. Metaxas, H. P., Rzayev, A. G., Isayeva, M. I. (2011). Seismic hazard parameters of the Shamakhi-Ismayilli earthquake focal zone. Catalog of seismic forecast observations on the territory of Azerbaijan, 314–321. Baku. 
30. Reilinger, R., McClusky, S., Vernant, P., et al. (2006). GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions. Journal of Geophysical Research: Solid Earth, 111(B5), B05411.
31. Kadirov, F., Mamedov, S., Reilinger, R., McClusky, S. (2010). Some data on modem tectonic deformation and active faulting in Azerbaijan (According to global positioning system measurement). Proceedings of Azerbaijan National Academy of Sciences, The Sciences of Earth, 1, 82–88.
32. Yetirmishli, G. D., Mammadli, T. Y., Ibragimova, L. A. (2017). Active faults of the territory of Azerbaijan and their possible impact on oil and gas fields of the Nizhnekura depression. Geology and Geophysics of the South of Russia, 3, 136–146.
33. Yusubov, N. P. (2017). On the existence of the West Caspian fault. Azerbaijan Oil Industry, 4, 12–17.
34. Yusubov, N. P. (2020). On the fault tectonics of depression zones of Azerbaijan based on seismic exploration data. SOCAR Proceedings, 3, 11–17.
35. Grachev, A. F. (2000). Neotectonics, geodynamics and seismicity of Northern Eurasia. Moscow: PROEL.
36. Senin, B. V., Kerimov, V. Yu., Mustaev, R. N., Leonchik, M. I. (2022). Structural and geodynamic systems of the basement of the Black Sea-Caspian region and their evolution in the late Paleozoic-Cenozoic. Geotectonics, 1, 27–50.
37. Kerimov, V. Yu., Rachinsky, M. Z. (2011). Geofluid dynamics of oil and gas potential of mobile belts. Moscow: Nedra.
38. Leonov, Yu. G., Volozh, Yu. A., Antipov, M. P., et al. (2010). Consolidated crust of the Caspian region: experience of zoning. Moscow: GEOS.
39. Rastsvetaev, L. M. (1980). Alpine structure of the south of Central Asia and adjacent regions /In: Tectonics of the mediterranean belt. Moscow: Nauka.
40. Kopp, M. L. (1982). Some issues of late Alpine geodynamics of the South-East Caucasus, Talysh and Nizhnekura depression. Problems of Geodynamics of the Caucasus, Moscow: Nauka.
41. (2008). Geology of Azerbaijan. Volume VII. Oil and Gas. Baku: Nafta-Press Publishing House.
42. Alizade, A. A., Guliyev, I. S., Mamedov, P. Z. (2018). Productive strata of Azerbaijan. In 2 Vols. Moscow: Nedra.
43. Kerimov, V. Yu., Mustaev, R. N., Etirmishli, G. D., Yusubov, N. P. (2021). Influence of modern geodynamics on the structure and tectonics of the Black Sea-Caspian region. Eurasian Mining, 35(1), 3–8.
44. Guliev, I. S., Yusubov, N. P., Guseynova, Sh. M. (2020). On the mechanism of formation of mud volcanoes in the South Caspian Basin based on 2D/3D seismic data. Physics of the Earth, 5, 131–138.
45. Kerimov, V., Rachinsky, M., Mustaev, R., Serikova, U. (2018). Geothermal conditions of hydrocarbon formation in the South Caspian basin. Iranian Journal of Earth Sciences, 10(1), 78-89.
46. Kerimov, V.Yu., Shilov, G.Ya., Mustayev, R.N., Dmitrievskiy, S.S. (2016). Thermobaric conditions of hydrocarbons accumulations formation in the low-permeability oil reservoirs of khadum suite of the Pre-Caucasus. Oil Industry, 2, 8–11.
47. Guliev, S., Mustaev, R.N., Kerimov, V.Y., Yudin, M.N. (2018). Degassing of the earth: Scale and implications. Gornyi Zhurnal 11, 38–42.

The South Caspian Basin (SCB) is a geologically complex and diverse region of significant scientific interest due to its hydrocarbon resources and intricate crustal structure. This study provides an updated interpretation of the SCB’s crustal configuration using gravity-derived data, with particular emphasis on delineating Moho depth and the influense of its variations on petroleum basins. The crustal structure of the basin is assessed using Bouguer gravity anomalies, incorporating terrestrial and marine gravity measurements, and processed with spectral analysis methods. Power spectrum analysis was applied to estimate the depths of subsurface mass distributions affecting the gravity field, enabling separation of regional and residual anomalies and providing an initial reference depth of Moho. These results served as input for Parker–Oldenburg inversion, an iterative Fourierbased technique used to model the Moho surface by minimizing discrepancies between observed and calculated gravity anomalies. The integrated approach reveals substantial lateral variations in Moho depth, ranging from approximately 42 km in the Absheron–Prebalkhan zone to about 29 km in the central SCB. Analysis of spatial correlations indicates that oil and gas reservoirs are primarily located in areas where the Moho surface is deeper and along gradient zones marking abrupt depth changes. These findings enhance understanding of the complex tectonic evolution of the SCB and provide valuable constraints for predicting potential hydrocarbon locations in this tectonically active and data-scarce region.

Keywords: South Caspian Basin; Bouguer gravity anomalies; spectral analysis; Parker–Oldenburg inversion; Moho depth; hydrocarbon reservoirs.

Date submitted: 11.06.2025     Date accepted: 08.09.2025

References

1. Kadirov, F., Floyd, M., Alizadeh, A., et al. (2012). Kinematics of the eastern Caucasus near Baku, Azerbaijan. Natural Hazards, 63, 997–1006.
2. Eppelbaum, L., Katz, Y., Kadirov, F., et al. (2025). Geodynamic, tectonophysical, and structural comparison of the South Caspian and Levant Basins: A review. Geosciences, 15, 281.
3. Kadirov, F., Mammadov, S., Reilinger, R., McClusky, S. (2008). Some new data on modern tectonic deformation and active faulting in Azerbaijan (according to global positioning system measurements). ANAS Transactions. Earth Sciences, 1, 82–88.
4. Kadirov, F., Yetirmishli, G., Safarov, R., et al. (2024). Results of 25 years (1998-2022) crustal deformation monitoring in Azerbaijan and adjacent territory using GPS. ANAS Transactions. Earth Sciences, 1, 28-43. 
5. Kerimov, V. Yu., Yusubov, N. P., Guliyev, I. S., Kadirov, F. A. (2025). A new approach to the oil and gas geological zoning of the territory of Azerbaijan. ANAS Transactions. Earth Sciences, 1, 52-67.
6. Zhang, Y., Wang, W., Li, L., et al. (2023). Influence of the Moho surface distribution on the oil and gas basins in China seas and adjacent areas. Acta Oceanologica Sinica, 42, 167–188.
7. Dehghani, G. A., Makris, J. (1983). The gravity field and crustal structure of Iran. In: Geodynamic Project (Geotraverse) in Iran: Final Report. Geological Survey of Iran.
8. (1990). Gravity map of the USSR. Scale 1:2,500,000. Moscow: Ministry of Geology USSR.
9. Kadirov, F. A. (2000). Application of the Hartley transform for interpretation of gravity anomalies in the Shamakhy–Gobustan and Absheron oil-and gas-bearing regions, Azerbaijan. Journal of Applied Geophysics, 45(1), 49–61.
10. Kadirov, F. A., Gadirov, A. H. (2014). A gravity model of the deep structure of South Caspian Basin along sub-meridional profile Alborz–Absheron Sill. Global and Planetary Change, 114, 66–74.
11. Kadirov, F. A., Klokočník, J., Eppelbaum, L. V., et al. (2023). Bouguer gravity data and satellite gravity transformation integration in the Caspian region: An introduction. ANAS Transactions. Earth Sciences, 1, 11–16.
12. Spector, A., Grant, F. S. (1970). Statistical models for interpreting aeromagnetic data. Geophysics, 35(2), 293–302.
13. Bhattacharyya, B. K., Leu, L. K. (1977). Spectral analysis of gravity and magnetic anomalies due to rectangular prismatic bodies. Geophysics, 42(1), 41–50.
14. Gomez-Ortiz, D., Tejero-Lopez, R., Babin-Vich, R., Rivas-Ponce, A. (2005). Crustal density structure in the Spanish Central System derived from gravity data analysis (Central Spain). Tectonophysics, 403, 131–149.
15. Oldenburg, D. W. (1974). The inversion and interpretation of gravity anomalies. Geophysics, 39(4), 526–536.
16. Blakely, R. J. (1995). Potential theory in gravity & magnetic applications. Cambridge University Press.
17. Braitenberg, C., Zadro, M., Fang, J., et al. (2000). The gravity and isostatic Moho undulations in Qinghai–Tibet plateau. Journal of Geodesy, 30, 489–505.
18. Parker, R. L. (1973). The rapid calculation of potential anomalies. Geophysical Journal of the Royal Astronomical Society, 31(4), 447–455.
19. Hartley, R. V. L. (1942). A more symmetrical Fourier analysis applied to transmission problems. Proceedings of the IRE, 30(2), 144–150.
20. Kulhânek, O. (1976). Introduction to digital filtering in geophysics. Elsevier.
21. Mangino, S., Priestley, K. (1998). The crustal structure of the southern Caspian region. Geophysical Journal International, 133(3), 630–648.
22. Baranova, E. P., Kosminskaya, I. P., Pavlenkova, N. I. (1990). The results of reinterpretation of DSS data over South Caspian region. Geophysical Journal, 12, 60–67.
23. Azerbaijan oil. https://www.travel-images.com/az-oil.html
24. Abdullayev, N. A., Kadirov, F., Guliyev, I. S. (2017). Subsidence history and basin-fill evolution in the South Caspian Basin from geophysical mapping, flexural backstripping, forward lithospheric modelling and gravity modelling. Geological Society, London, Special Publications, 427, 175–196.

This study focuses on a comprehensive investigation of the deep structure of the Earth's crust and upper mantle in Azerbaijan and the adjacent Caspian Sea region, within the tectonic framework of the Caucasus orogen. The main objective is to reconstruct the layered-block structure of the crust, refine the spatial distribution of earthquake hypocenters, and identify key tectonic features, including subduction zones and active faults. To achieve these goals, seismic tomography was applied using an improved double-difference method (TomoDD-SE), which enables simultaneous determination of P- and S-wave velocity structures and precise localization of earthquake hypocenters. The dataset comprises the seismic catalog of the Republican Seismological Service Center of Azerbaijan for the period 2011–2023, which includes approximately 7500 local earthquakes (magnitude ≥ 2.0) recorded by 47 broadband stations, as well as additional stations in Georgia and Turkey. The data were processed using a three-dimensional velocity grid developed with the VELEST program and validated through checkerboard resolution tests. The results confirm a layered-block structure of the crust with sharp velocity boundaries and a thick sedimentary cover (up to 25 km) in the South Caspian Basin. The TomoDD method supports the oceanic origin of the crystalline basement beneath the Kura–Araz Basin and reveals ongoing subduction beneath the eastern Greater Caucasus. Refined hypocenter locations show alignment with active tectonic structures, such as the Main Caucasus Thrust, the Kura Fold Zone, and the Western Caspian Fault. Low-velocity zones associated with the sedimentary cover and high-velocity anomalies corresponding to the crystalline basement and upper mantle were identified.

Keywords: seismic tomography; double-difference method (TomoDD-SE); Earth’s crust; velocity models; Caucasus orogen; Kura–Aras Basin; subduction; Main Caucasus Thrust; Western Caspian Fault; sedimentary cover.

Date submitted: 02.06.2025     Date accepted: 05.09.2025

References

1. Ismail‐Zadeh, A., Adamia, S., Chabukiani, A., et al. (2022). Geodynamics, seismicity, and seismic hazards of the Caucasus. Earth-Science Reviews, 207, 103222.
2. Waldhauser, F. (2001). HypoDD—a program to compute double-difference hypocenter locations. U.S. Geological Survey Open-File Report 01-113. https://pubs.usgs.gov/of/2001/0113/report.pdf
3. Kazimova, S. E. (2020). Redefinition of earthquake hypocenters by the double difference method. Geology and Geophysics of the South of Russia, 10(4), 41–51.
4. Geiger, L. (1912). Probability method for determination of earthquake epicenters from the arrival times only. Bulletin of St. Louis University, 8, 60–71.
5. Thurber, C. H. (1983). Earthquake locations and three-dimensional crustal structure in the Coyote Lake area, central California. Journal of Geophysical Research, 88(B10), 8226–8236.
6. Thurber, C. H., Zhang, H., Waldhauser, F., et al. (2006). Three-dimensional compressional wavespeed model, earthquake relocations, and focal mechanisms for the Parkfield, California, region. Bulletin of the Seismological Society of America, 96(4B), S38–S49.
7. Zhang, H., Thurber, C. H. (2003). Double-difference tomography: The method and its application to the Hayward Fault, California. Bulletin of the Seismological Society of America, 93(5), 1875–1889.
8. Godoladze, T., Gok, R., Onur, T., et al. (2024). Compilation of a comprehensive earthquake catalog and relocations in the Caucasus region. Seismological Research Letters, 95(2A), 1066-1081.
9. Yetirmishli, G. C., Kazimova, S. E., Kazimov, I. A. (2011). One-dimensional velocity model of the Earth's crust in the territory of Azerbaijan from local earthquake data. Journal of Geodynamics, 51(1), 71–78.
10. Kazimova, S. E., Kazimov, I. A. (2017). 3D seismic tomography model of the crust in the territory of Azerbaijan and adjacent regions. ANAS Transactions. Earth Sciences, 2, 23–31.
11. Gunnels, M., Yetirmishli, G., Kazimova, S., Sandvol, E. (2021). Seismotectonic evidence for subduction beneath the Eastern Greater Caucasus. Geophysical Journal International, 224(3), 1825–1842.
12. Mosar, J., Kangarli, T., Sosson, M., et al. (2010). Caucasus–Arabian belt collision and the current tectonic configuration of the Caucasus region. Geological Society, London, Special Publications, 340(1), 261–280.
13. Babayev, G., Yetirmishli, G., Triep, E., Turkelli, N. (2010). Seismic hazard assessment in Azerbaijan region. Journal of Seismology, 14(3), 569–588.
14. Tan, O., Taymaz, T., Yolsal-Chevikbilen, S. (2006). Source parameters and rupture characteristics of the 2002 Mw 6.5 Afyon earthquake (western Turkey) from teleseismic body-wave inversion. Geophysical Journal International, 166(2), 617–628.
15. Forte, A. M., Cowgill, E., Bernard, R., Kreylos, O. (2013). Late Cenozoic deformation of the Kura fold-thrust belt, eastern Georgia. Tectonics, 32(1), 1–24.
16. Allen, M. B., Vincent, S. J., Wheeler, P. J. (2002). Late Cenozoic tectonics of the South Caspian Basin. Journal of the Geological Society, 159(5), 665–671.
17. Allen, M. B., Vincent, S. J., Alsop, G. I., et al. (2003). Late Cenozoic deformation in the South Caspian region: Effects of a rigid basement block within a collision zone. Tectonophysics, 366(3–4), 223–239.
18. Khain, V. E., Shikombaev, C. A., Terekhov, A. G. (1966). On the deep structure of the South Caspian depression. Geology of Oil and Gas, 1, 25–34.
19. Reilinger, R., McClusky, S., Vernant, P., et al. (2006). GPS constraints on continental deformation in the Africa–Arabia–Eurasia continental collision zone and implications for the dynamics of plate interactions. Journal of Geophysical Research: Solid Earth, 111(B5), B05411.
20. Kazimin, M. I., Verzhbitskii, E. V. (2011). On the nature of subduction under the Greater Caucasus: New seismic data. Geotectonics, 45(3), 193–209.
21. Jackson, J., Priestley, K., Allen, M., Berberian, M. (2002). Active tectonics of the South Caspian Basin. Geophysical Journal International, 148(2), 214–245.
22. Mansouri-Far, C. (2016). Heat flow and geothermal structure of the South Caspian Basin. Geothermics, 60, 104–117.
23. Mellors, R. J., Yetirmishli, G. C., Maharramov, A. M., Gasanov, A. A. (2012). Seismicity and active tectonics of Azerbaijan. Seismological Research Letters, 83(1), 35–41.
24. Mellors, R. J., Jackson, J., Myers, S., et al. (2012). Deep earthquakes beneath the Northern Caucasus: Evidence of active or recent subduction in Western Asia. Bulletin of the Seismological Society of America, 102(2), 862–866.
25. Allam, A. A., Ben-Zion, Y. (2012). Seismic velocity structures in the Southern California plate-boundary environment from double-difference tomography. Geophysical Journal International, 190(2), 1181–1196.
26. Mumladze, T., Mosar, J., Sosson, M., Adamia, S. (2015). The eastern termination of the Greater Caucasus: Evolution of tectonic structures within the transition between the Greater and Lesser Caucasus (Georgia). Geologica Carpathica, 66(5), 427–440.
27. Tye, A. R., Niemi, N. A., Cowgill, E., et al. (2022). Diverse deformation mechanisms and lithologic controls in an imbricate fan: Insights from the Greater Caucasus. Tectonics, 41(12), e2022TC007349.
28. Vincent, S. J. (2016). Tectonics of the Greater Caucasus: A review of recent studies. Earth-Science Reviews, 160, 1–20.
29. Vincent, S. J. (2018). Reactivation of steeply dipping Mesozoic normal faults in the Greater Caucasus. Tectonics, 37(4), 1050–1071.

The article examines the properties of polymer-based drilling fluids formulated with natural polymers such as starch, cellulose-derived biopolymers, and lignosulfonates. The research focuses on key parameters – pseudoplasticity and filtration characteristics – critical for cleaning horizontal and deviated wellbores. Effective penetration into productive formations is achieved by minimizing filtrate intrusion and reservoir contamination, assessed via penetration depth based on adsorption properties of the reagents. A synergistic effect is observed when high-molecular-weight polysaccharides – xanthan gum, modified starch, and lignosulfonate – are combined, forming a protective screen within the pore channels of the formation through adsorption. Optimized quadratic equations predict flow behavior index and consistency index values for starch concentrations up to 0.4% and xanthan gum up to 3%. Joint application of starch and xanthan gum reduces the fluid filtration index 1.6-fold, lowers the flow behavior index 1.02-fold, and increases the consistency index nearly 1.2-fold. The best filtration and transport properties are achieved with 1.5% starch + 0.2% xanthan gum and 2% starch + 0.25% xanthan gum. The developed predictive method for polymer composition penetration is validated through experiments on limestone cores from the Yugomashevskoye field, evaluating the effect of polymer formulations on filtration-capacity properties.This approach enables optimization of polymer reagent concentrations, ensuring efficient use of costly additives and reducing well construction costs. It also supports safe drilling conditions, effective drill cuttings suspension, and improved cuttings transport. A visual model of the proposed solution is provided.

Keywords: biopolymer reagents; cellulose; lignosulfonate; adsorption; oil; productive formation; drilling fluid.

Date submitted: 05.06.2025     Date accepted: 31.08.2025

References

1. Suleimanov, B. A., Veliyev, E. F. , Vishnyakov, V. V. (2022). Nanocolloids for petroleum engineering: Fundamentals and practices. John Wiley & Sons.
2. Loginova, M. E., Chetvertneva, I. A., Movsumzade, E. M., et al. (2023). Optimization of concentrations of drilling reagents based on gums using mathematical modeling methods. Rossijskij Khimicheskij Zhurnal, LXVII(1), 3-10.
3. Krylov, V. I., Kretsul, V. V. (2002). Rheological modeling of biopolymer drilling fluids. Oil Recovery, 5, 16–20.
4. Girfanov, V. T., Loginova, M. E. (2018). Study of rheological properties of drilling mud. In: Proceedings of the III Scientific and Practical Conference with International Participation «Oil and gas complex: problems and innovations», Ufa.
5. Loginova, M. E., Chetvertneva, I. A., Movsumzade, E. M., et al. (2023). Optimizing drilling reagent concentrations based on gums through mathematical modeling methods. Russian Journal of General Chemistry, 93(6), 1584-1590.
6. Vishnyakov, V. V., Suleimanov, B. A., Salmanov, A. V., Zeynalov, E. B. (2019). Primer on enhanced oil recovery. Gulf Professional Publishing.
7. Suleimanov, B. A. (2004). On the effect of interaction between dispersed phase particles on the rheology of fractally heterogeneous disperse systems. Colloid Journal, 66(2), 249–252.
8. Chetvertneva, I. A., Antonov, K. V., Movsumzade, E. M., Loginova, M. E. (2024). Development and application of polymer reagents in drilling fluids during construction of oil and gas wells and production of hydrocarbon raw materials. Ufa: Ufa State Petroleum Technical University.
9. Zhukhovitsky, S. Yu. (1976). Flushing fluids in drilling. Moscow: Nedra.
10. Gorodnov, V. D. (1985). Drilling fluids. Moscow: Nedra.
11. Bulatov, A. I., Proselkov, Yu. M., Ryabchenko, V. I. (1981). Well flushing technology. Moscow: Nedra.
12. Heinze, T., Koschella, A. (2005). Carboxymethyl ethers of cellulose and starch. Macromolecular Symposia, 223(1), 13–40.
13. Gray, J. R., Darley, G. S. (1985). Composition and properties of drilling agents (flushing fluids). Moscow: Nedra.
14. Aleksandrova, G. Yu., Mosvum-zade, N. Ch., Makhmutova, R. I., Chuvashov, D. A. (2011). Stages of the origin and development of quantum-chemical calculations. History and Pedagogy of Natural Science, 1, 42-49.
15. Rogovina, S. Z., Prut, E. V., Berlin, A. A. (2019). Composite materials based on synthetic polymers reinforced with fibers of natural origin. High-Molecular Compounds. Series A, 61(4), 291–315.
16. Koshelev, V. N., Vakhrushev, L. P., Belenko, E. V., Lushpeeva, O. A. (2001). Polymer-dispersed synergetic phenomena and new drilling fluid systems. Oil Industry, 4, 22–23.
17. Vakhrushev, L. P., Koshelev, V. N., Penkov, A. I., Belenko, E. V. (2001). Spatially structured aqueous clay-free solutions. Oil Industry, 9, 40–43.
18. Afanasyev, N. I., Teltevskaya, S. E., Makarevich, N. A., Parfenova, L. N. (2005). Structure and physicochemical properties of lignosulfonates. Ekaterinburg: Ural Branch of the Russian Academy of Sciences.
19. Loginova, M. E., Kolchina, G. Yu., Movsumzade, E. M. (2023). Kinetics of monomolecular adsorption of reagent systems. Chemchemtech, 66(4), 60-67.
20. Kolchina, G. Yu., Teptereva, G. A., Karimov, O. Kh., et al. (2022). Heteroatomic modifiers in the processes of adsorption and membrane diffusion, Chemchemtech, 65(6), 12–19. 
21. Loginova, M. E., Movsumzade, E. M., Teptereva, G. A., et al. (2022). Variability of monomolecular adsorption of lignosulfonate systems. Rossijskij Khimicheskij Zhurnal, 66(1), 35-41.
22. Suleimanov, B. A. , Veliyev, E. F. , Naghiyeva, N. V. (2021). Colloidal dispersion gels for in-depth permeability modification. Modern Physics Letters B, 35(1), 2150038.
23. Ryabova, L. M., Chetvertneva, I. A. (1997). Polymer solutions based on new polymer reagents of complex action. Environmental problems and ways of solving problems on the long-term zone of introduction of geological exploration and drilling operations. In: Proceedings of the All-Russian Scientific-Practical Conference, Tyumen.
24. Kondrashev, O. F., Chetvertneva, I. A. (2005). Insulating properties of lightweight biopolymer drilling mud. Ufa: Bashnipineft.
25. Ryabchenko, V. I. (1990). Control of properties of drilling fluids. Moscow: Nedra.
26. Moldabayeva, G. Z., Efendiyev, G. M., Kozlovskiy, A. L., et al. (2023). Study of the rheological characteristics of sediment-gelling compositions for limiting water inflows. Applied Sciences, 13(18), 10473.
27. Kravchenko, I. I. (1971). Adsorption of surfactants in oil production processes. Moscow: Nedra.
28. Suleimanov, B. A., Rzayeva, S. C., Akhmedova, U. T. (2021). Self-gasified biosystems for enhanced oil recovery. International Journal of Modern Physics B, 35(27), 2150274.
29. OST 39-195-86. (1987). Oil. Method for determining the coefficient of oil displacement by water under laboratory conditions. Moscow: VNIIOENG.

This research presents a comprehensive methodology for calculating the bending of the drive shaft in a novel continuous deflector, designed to enable directional drilling with simultaneous coring in mineral exploration. The study addresses a critical industry gap: existing deflection tools (e.g., wedge deflectors, small-diameter motors) are incompatible with core recovery in curved sections and often induce excessive wellbore curvature, exceeding the fatigue limits of standard exploration drill strings. The proposed deflector design innovatively adapts the point-the-bit principle, incorporating a hollow drive shaft bent via two rotating eccentric bushings (eccentricity 2.5 mm each). This allows for controlled wellpath deviation while housing a retrievable core barrel. The device includes a hydraulic fixation system to anchor the tool body and a spherical bearing to maintain shaft alignment during bending. The core of the study is an analytical model based on the initial parameters method, treating the drive shaft as a statically indeterminate beam with rigid and hinged supports. The model derives equations for shaft displacement, bit tilt angle, and resultant wellbore curvature intensity as functions of the bushing rotation angle. Parametric analysis confirms that the curvature intensity can be precisely controlled from 0 to 0.3°/m, remaining within the stringent allowable limit of 1.0°/3 m for NQ-size drill pipes. The deflector’s design, with a total length of 3.2 m, also satisfies the geometric constraint of fitting into the minimum achievable curvature radius of 191 m. This work provides a validated theoretical foundation for a tool that significantly enhances exploration efficiency by reducing drilling volume and improving geological data accuracy through core recovery in deviated wellbores.

Keywords: continuous deflector; core extraction drilling; directional drilling; artificial curvature of wells; extractable core application.

Date submitted: 16.05.2025     Date accepted: 27.08.2025

References

1. Oberle, B., Bringezu, S., Hatfield-Dodds, S., et al. (2019). Global resources outlook: 2019. France, Paris: International Resource Panel, United Nations Envio.
2. Blinov, P. A., Shansherov, A. V., Lobachev, I. M., Volkov, A. R. (2024). Evaluation of strength properties of cement containing NaCl in mixing water for cementing wells in halite strata. International Journal of Engineering, 37(10), 2109-2115.
3. Dvoynikov, M. V., Minaev, Ya. D., Minibaev, V. V., et al. (2024). Technology for killing gas wells at managed pressure. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 335(1), 7–18.
4. Litvinenko, V., Bowbriсk, I., Naumov, I., Zaitseva, Z. (2022). Global guidelines and requirements for professional competencies of natural resource extraction engineers: Implications for ESG principles and sustainable development goals. Journal of Cleaner Production, 338, 130530.
5. Blinov, P. A., Sadykov, M. I., Gorelikov, V. G., Nikishin, V. V. (2024). Development and research of backfill compounds with improved elastic and strength properties for oil and gas well lining. Journal of Mining Institute, 268, 588-598.
6. Fatehi, M., Asadi Haroni, H., Hossein-Morshedy, A. (2017). Designing infill directional drilling in mineral exploration by using particle swarm optimization algorithm. Arabian Journal of Geosciences, 10, 1-14.
7. Caers, J., Scheidt, C., Yin, Z., et al. (2022). Efficacy of information in mineral exploration drilling. Natural Resources Research, 31(3), 1157-1173.
8. Yang, M., Hu, Y., Liu, B., et al. (2023). Application of artificial neural networks for identification of lithofacies by processing of core drilling data. Applied Sciences, 13(21), 119-134.
9. Hossein-Morshedy, A., Khorram, F., Emery, X. (2023). A multi-objective approach for optimizing the layout of additional boreholes in mineral exploration. Minerals, 13(10), 1252.
10. Nwosu, J. I., Egesi, N. (2021). Predicting the true reserve of a steeply dipping deposit in a multi-deviation angle exploration operation. Journal of Mining and Geology, 57(2), 397-406.
11. Hapugoda, S., Manuel, J. R. (2010). A comparison of drilling and sampling techniques as they relate to base and precious metal exploration in the Mt Isa Inlier of North West Queensland and the southern Lachlan Fold Belt in New South Wales. In: Proceedings Sampling Conference, Perth, WA, 11-12 May.
12. Тomskii, К. О., Ivanova, M. S. (2024). Optimization of the location of a multilateral well in a thin oil rim, complicated by the presence of an extensive gas cap. Journal of Mining Institute, 265, 140-146.
13. Dvoynikov, M. V., Nikitin, V. I., Kopteva, A. I. (2024). Analysis of the methodology for selecting the rheological model of cement slurry for determining the technological parameters of well casing. International Journal of Engineering, Transactions A: Basics, 37(10), 2042-2050.
14. Leusheva, E., Alikhanov, N., Tabatabaee Moradi, S. S. (2024). Experimental evaluation of the influence of the physico-chemical properties of surfactants on the process of drilling in pay-zones. International Journal of Engineering, 38(4), 819-829.
15. Zhang, C., Zou, W., Cheng, N. (2016). Overview of rotary steerable system and its control methods. In: 2016 IEEE International Conference on Mechatronics and Automation, Harbin, China.
16. Zhdaneev, O. V., Zaytsev, А. V., Prodan, Т. T. (2021). Possibilities for creating Russian high-tech bottomhole assembly. Journal of Mining Institute, 252, 872-884.
17. Ma, T., Chen, P., Zhao, J. (2016). Overview on vertical and directional drilling technologies for the exploration and exploitation of deep petroleum resources. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2, 365-395.
18. Huang, W., Wang, G., Gao, D. (2021). A method for predicting the build-up rate of ‘push-the-bit’rotary steering system. Natural Gas Industry B, 8(6), 622-627.
19. Schaaf, S., Mallary, C. R., Pafitis, D. (2000). Point-the-bit rotary steerable system: Theory and field results. SPE-63247-MS. In: SPE Annual Technical Conference and Exhibition, Dallas, Texas, October.
20. Sosnovskaya, E. L., Avdeev, A. N. (2020). Forecast of the stability of the array of gold ore deposits based on the analysis of core material from exploration core drilling wells. Mining Informational and Analytical Bulletin, 3-1, 216-223.
21. Mohamed, A., Salehi, S., Ahmed, R. (2021). Significance and complications of drilling fluid rheology in geothermal drilling: A review. Geothermics, 93, 1020-1066.
22. Zhou, Z., Hu, Y., Liu, B., et al. (2023). Development of automatic electric drive drilling system for core drilling. Applied Sciences, 13(2), 105-109.
23. Nutskova, M. V., Alhazzaa, M., Alhazaa, A. (2025). Effect of mineral wool impregnated with carbon nanotubes on properties of cement at high temperatures. International Journal of Engineering, 38(1), 148-155.
24. Dvoynikov, M. V., Kutuzov, P. A. (2025). Analysis of efficiency of communication channels for monitoring and operational control of oil and gas wells drilling process. International Journal of Engineering, 38(1), 120-131.
25. Drenth, Ch. (2017). Know your limits: Drill rod bending capabilities and deviated hole applications. Coring Magazine, 5, 16-19.
26. Lachinyan, L. A., Medvedev, A. K. (2021). Justification of the design of the drill string threaded connection as a part of the complexes of drilling shells with a removable core receiver. Exploration and Protection of Subsoil, 5, 38-44.
27. Stepanchukova, A. V. (2021). Review of modern world technologies of pipe manufacturing used in exploration drilling. Step in Science, 1, 98-101.
28. Drenth, Ch. (2019). Bulletin CDDA technical committee. Borehole deviation guidelines. In: 2019 Annual Canadian Diamond Drilling Association AGM Conference.
29. Ryazanov, V. I., Spiridonov, B. I. (1976). Analysis of principle schemes of deflectors. Proceedings of Tomsk Polytechnic University. Engineering of Georesources, 260, 75-77. 30. Neskoromnykh, V. V., Pushmin, P. S., Nadelyaev, A. A., Fadeeva, L. S. (2008). Main directions of improvement of the technology of artificial well curvature in hard and hard rocks. Earth Sciences and Subsoil Use, 32(6), 186-190.
30. Stroud, D., Russell, M., Peach, S. (2003). Development of the industry's first slimhole point-the-bit rotary steerable system. SPE-84449-MS. In: SPE Annual Technical Conference and Exhibition, Denver, Colorado, October.
31. Neskromnykh, V. V., Popova, M. S., Golovchenko, A. E., et al. (2020). Method of drilling process control and experimental studies of resistance forces during bits drilling with PDC cutters. Journal of Mining Institute, 245, 539-546.
32. Menand, S., Christophe, S., Gerbaud, L., et al. (2012). PDC Bit Steerability Modeling and Testing for Push-the-bit and Point-the-bit RSS. SPE-151283-MS. In: IADC/SPE Drilling Conference and Exhibition, San Diego, California, USA, March.
33. Wang, R., Xue, Q., Han, L., et al. (2014). Torsional vibration analysis of push-the-bit rotary steerable drilling system. Meccanica, 49, 1601-1615.
34. Blinov, P. A., Nikishin, V. V., Silichev, N. М. (2024). Device for directional drilling with coring. RU Patent 2832393.
35. Akbulatov, T. O., Levinson, L. M., Khasanov, R. A. (2008). Determination of the calculated radius of wellbore curvature during the operation of rotary steerable systems (RSS). Oil and Gas Business, 6(2), 29-33.

Accurate prediction of lithological layers during drilling operations remains a fundamental challenge that directly impacts drilling efficiency, wellbore stability, and overall hydrocarbon exploration success. Traditional formation evaluation methods often rely on periodic sampling or wireline logging, which can introduce delays and limit real-time decision-making capabilities during critical drilling phases. This study presents a machine learning approach for real-time lithology prediction using continuously measured drilling parameters from the Ca Tam oil field, offshore Vietnam. The study utilized seven key drilling parameters: weight on bit (WOB), rotary speed (RPM), torque, standpipe pressure (SPP), rate of penetration (ROP), mud weight (MW IN), and flow rate (FLW). These measurements were collected from multiple wells across the Ca Tam field, representing diverse geological conditions and operational scenarios. Data preprocessing involved removing outliers to focus on measurements representing actual formation properties. Subsequently, feature selection analysis identified the most discriminative parameters for lithological classification, focusing on variables that behave differently in each rock type. Four supervised machine learning algorithms were implemented and compared: Random Forest, Gradient Boosting (XGBoost), Support Vector Machines, and Artificial Neural Networks. Each model was trained to classify formations into three primary lithological categories: Sand, Claystone, and Shale. The Random Forest algorithm achieved the best performance, demonstrating the highest cross-validation accuracy and showing good generalization capabilities when tested on independent well data. Model validation confirmed consistent performance across varying geological conditions, successfully handling the complex stratigraphic variations characteristic of the Cuu Long basin. This approach provides real-time formation identification, improving drilling decisions and reducing operational costs.

Keywords: lithology; drilling data; machine learning; data-driven.

Date submitted: 03.06.2025     Date accepted: 01.09.2025

References

1. dos Santos Barbosa, M., Duarte Gonzaga, I. M., da Silva Vilar, D., et al. (2022). Cost analysis of drilling operations of an offshore well with four phases. Journal of Engineering Research, 2(6).
2. Pessier, R., Fear, M. (1992). Quantifying common drilling problems with mechanical specific energy and a bit-specific coefficient of sliding friction. SPE-24584-MS. In: SPE Annual Technical Conference and Exhibition, Washington, D.C., October. Society of Petroleum Engineers.
3. Efendiyev, G., Mammadov, P., Piriverdiyev, I., Mammadov, V. (2018). Estimation of the lost circulationrate using fuzzy clustering of geological objects by petrophysical properties. Visnyk of Taras Shevchenko National University of Kyiv. Geology, 2(81), 28–33.
4. Chernikov, A. D., Eremin, N. A., Stolyarov, V. E., et al. (2020). Application of artificial intelligence methods for identifying and predicting complications during the construction of oil and gas wells: problems and main directions of solutions. Georesources, 22(3), 87–96.
5. Dmitrievsky, A. N., Eremin, N. A., Safarova, E. A., et al. (2020). Qualitative analysis of time-series geodata for preventing complications and emergency situations during the drilling of oil and gas wells. SOCAR Proceedings, 3, 31–37.
6. Cuddy, S. J., Glover, P. W. J. (2002). The application of fuzzy logic and genetic algorithms to reservoir characterization and modeling. Soft Computing for Reservoir Characterization and Modeling, 1, 219–241.
7. Efendiyev, G. M., Mammadov, P. Z., Piriverdiyev, I. A. (2019). Modeling and evaluation of rock properties based on integrated logging while drilling with the use of statistical methods and fuzzy logic. In: Aliev, R., Kacprzyk, J., Pedrycz, W., Jamshidi, M., Babanli, M., Sadikoglu, F. (eds) 10th International Conference on Theory and Application of Soft Computing, Computing with Words and Perceptions - ICSCCW-2019. ICSCCW 2019. Advances in Intelligent Systems and Computing, vol 1095. Springer, Cham.
8. Efendiyev, G. M., Karazhanova, M. K., Piriverdiyev, I. A., et al. (2024). B.Assessment of the characteristics of the geological section of wells based on probabilistic-fuzzy analysis of complex geophysical and geological-technological information. SOCAR Proceedings, 3, 3-8.
9. Bourgoyne, A. T., Millheim, K. K., Chenevert, M. E., Young, F. S. (1991). Applied drilling engineering. 2nd ed. Society of Petroleum Engineers.
10. Caers, J., Zhang, T. (2004). Multiple-point geostatistics: A quantitative vehicle for integrating geologic analogs into reservoir modeling. AAPG Memoir, 80, 383–394. 
11. Rider, M. H. (2002). The geological interpretation of well logs. 2nd ed. Rider-French Consulting Ltd.
12. Serra, O. (2007). Well logging and reservoir evaluation. Editions Technip.
13. Asquith, G., Krygowski, D. (2004). Basic well log analysis. 2nd ed. American Association of Petroleum Geologists.
14. Gong, K., Ye, Zh., Chen, D., et al. (2018). Investigation on automatic recognition of stratigraphic lithology based on well logging data using ensemble learning algorithm. SPE-192006-MS. In: The SPE Asia Pacific Oil and Gas Conference and Exhibition, Brisbane, Australia, October.
15. Sun, J., Li, Q., Chen, M., et al. (2019). Optimization of models for a rapid identification of lithology while drilling - A winwin strategy based on machine learning. Journal of Petroleum Science and Engineering, 176, 321–341.
16. Gang, C. (2020). Study on realtime lithology identification method of LWD. IOP Conference Series: Earth and Environmental Science, 546, 052007.
17. Ren, X., Hou, J., Song, S., et al. (2019). Lithology identification using well logs: A method by integrating artificial neural networks and sedimentary patterns. Journal of Petroleum Science and Engineering, 182, 106336.
18. Efendiyev, G. M., Mammadov, P. Z., Piriverdiyev, I. A. (2019, August). Modeling and evaluation of rock properties based on integrated logging while drilling with the use of statistical methods and fuzzy logic. In: 10th International Conference on Theory and Application of Soft Computing, Computing with Words and Perceptions, ICSCCW-2019, 1095, 503-511.
19. Zhang, J., Liu, Y., Ma, Y., et al. (2024). Real-time lithology identification from drilling data with self & cross attention model and wavelet transform. Geoenergy Science and Engineering, 244, 213427.
20. Li, T.-T., Xiang, R.-Y., Jiao, T., Yan, X.-D. (2022). Research on intelligent lithology identification method based on realtime data of drilling wells. In: 2022 4th International Conference on Robotics, Intelligent Control and Artificial Intelligence (RICAI 2022), December 16–18, Dong-guan, China. ACM.
21. Moazzeni, A., Haffar, M. A. (2015). Artificial intelligence for lithology identification through real-time drilling data. Journal of Earth Science and Climatic Change, 6(3), 1–4.
22. Agrawal, R., Malik, A., Samuel, R., Saxena, A. (2021). Real-time prediction of litho-facies from drilling data using an artificial neural network: A comparative field data study with optimizing algorithms. Journal of Energy Resources Technology, 144(4), 043003.
23. Mahmoud, A. A., Elkatatny, S., Al-AbdulJabbar, A. (2021). Application of machine learning models for real-time prediction of the formation lithology and tops from the drilling parameters. Journal of Petroleum Science and Engineering, 203, 108574.
24. Khalifa, H., Tomomewo, O. S., Ndulue, U. F., Berrehal, B. E. (2023). Machine learning-based real-time prediction of formation lithology and tops using drilling parameters with a web App Integration. Eng, 4(3), 2443–2467.
25. Elkatatny, S., Al-AbdulJabbar, A., Mahmoud, A. A. (2024). Automated real-time prediction of geological formation tops during drilling operations: an applied machine learning solution for the Norwegian Continental Shelf. Journal of Petroleum Exploration and Production Technology, 14, 1661-1703.
26. Hansen, T. F., Erharter, G. H., Liu, Z., Torresen, J. (2024). A comparative study on machine learning approaches for rock mass classification using drilling data. Applied Computing and Geosciences, 24, 100199.
27. Azar, J. J., Samuel, G. R. (2007). Drilling engineering. PennWell Books.

Hydrocarbon production at fields with hard-to-recover reserves in complex mining and geological conditions requires solving complex reinforcement problems, the key one being ensuring high-quality delineation of productive horizons. The aim of the work is to evaluate and test the DRCT (Commercial name of plugging material) composite plugging material, which has improved performance characteristics for reliable well support and effective formation isolation, taking into account the quality of the cement stone. The influence of drilling fluid impurities on the structure of the cement stone was studied. It was found that their presence causes defects in the microstructure and insulation screen, which was confirmed by Radial Bond Tool (RBT) measurements in test wells.Testing was carried out on cementing slurries based on DRCT and Portland cement PCT I-100, prepared with fresh water containing 20% sodium chloride. The results of the studies showed the superiority of DRCT in terms of rheological properties, strength and brittleness of cement stone. Quantitative elemental analysis and X-ray phase analysis (XPA) of DRCT cement stone were performed. The structural formation features and strength characteristics were studied over eight years of operation in aggressive environments. The material proved to be highly resistant to degradation and maintained its strength in difficult conditions.Examples of recipe development and successful testing of DRCT material in wells confirmed its technological feasibility and effectiveness in complex reinforcement.

Keywords: well; cementing; plugging mud; cement stone; strength of cement stone.

Date submitted: 11.05.2025     Date accepted: 03.09.2025

References

1. Vorobyov, A. E. (2008). The estimation of world hydrocarbon reserves and the need for specialists in the field of fuel and energy sector. Drilling and Oil, 1, 54-56.
2. (2025). Energy Security of the World: TOP 25 forecasts for 2025. https://armyinform.com.ua/2025/01/01/energetychna-bezpeka-svitu-top-25-prognoziv-na-2025-rik/
3. Lukin, O. Yu. (2008). Hydrocarbon potential of the mineral resources of Ukraine and the main directions of its development. Bulletin of the National Academy of Sciences of Ukraine, 4, 56-67.
4. (2021). Analysis of the global gas market. Oil and Gas of Ukraine. https://oil-gas.com.ua/novyny https://www.naftogaz. com/news/naftogaz-annual-report-2021.
5. (2025). Natural gas production and reserves in the world countries. SKAT-TRADE https://skat-trade.com/eng/
6. Lukin, O. Yu., Gafych, I. P., Goncharov, G. G., et al. (2020). Hydrocarbon potential in entrails of the earth of Ukraine and main trend of its development. Mineral Resources of Ukraine, 4, 28-38.
7. Rudko, G. I. (2020). Resource potential of mineral resources of Ukraine: its study and exploitation. In: The V International Exhibition of Mining, Coal and Construction Industry. «MiningWorldUkraine, Zaporizhzhia, Ukraine, 07-09 October.
8. Romanyuk, O. M. Practices of implementing production enhancement contracts and production sharing agreements. https://oil-gas.com.ua/articles/Practices-of-Implementing-Production-Enhancement-Contracts-and-Production-Sharing-Agreements
9. Hossain, M., Islam, M. (2018). Drilling engineering: problems and solutions. Scrivener Publishing.
10. Yan, Y., Guan, Z., Xu, Y., et al. (2019). Numerical investigation of perforation to cementing interface damage area. Journal of Petroleum Science and Engineering, 179, 257-265.
11. Pinka, Ja., Vytyaz, O. (2016). Effect of fracture pressures on the selection of depths for casing setting in Slovakia. Mining of Mineral Deposits, 10(4), 37-43.
12. Amit, K., Tareq, D., Ali, S., et al. (2019). Near real-time corrosion monitoring for wellbore integrity management. SPE-197517-MS. In: The Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, UAE, November.
13. Suleimanov, B. A., Veliyev, E. F., Vishnyakov, V. V. (2022). Nanocolloids for petroleum engineering: Fundamentals and practices. John Wiley & Sons.
14. Guan, Z., Chen, T., Liao, H. (2021). Theory and technology of drilling engineering. Singapore: Springer.
15. Koroviaka, Ye., Stavychnyi, Ye., Martsynkiv, O., et al. (2024). Research on occurrence features and ways to improve the quality of productive hydrocarbon horizons demarcation. Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, 3, 5-11.
16. Stavychnyi, Y., Koroviaka, Y., Ihnatov, A., et al. (2024). Fundamental principles and results of deep well lining. IOP Conference Series: Earth and Environmental Science, 1348, 012077.
17. Piatkivskyi, S., Stavychnyi, Y., Femiak, Y., et al. (2024). Well rehabilitation is a promising area for increasing hydrocarbon production. Strojnícky Časopis - Journal of Mechanical Engineering, 74(1), 141-158.
18. Yijin, Z., Peiqing, L., Qian, T., et al. (2021). Experimental study and analysis on the microstructure of hydration products on the well cementation second interface and interface strengthening strategies. Journal of Petroleum Science and Engineering, 207, 109095.
19. Vytyaz, O., Chernova, O., Stavychnyi, Ye., et al. (2024). Increasing the reliability of oil and gas well fastening with polycomponent plugging systems. Mining of Mineral Deposits, 18(3), 82-93.
20. Suleimanov, B. A., Veliyev, E. F., Aliyev, A. A. (2023). Oil and gas well cementing for engineers. John Wiley & Sons.
21. Alkhamis, M., Imqam, A. (2021). A simple classification of wellbore integrity problems related to fluids migration. Arabian Journal for Science and Engineering, 46, 6131-6141.
22. (2014). TU U 20.1-38821257-001:2014. Dry plugging mixtures. Energo Composite LLC, Lviv., Ukraine.
23. (1999). DSTU B V.2.7-88-99. Оil-well роrtland сеmепts. Spесifications. Kiyev: State Committee for Construction, Architecture and Housing Policy.
24. (1999). DSTU B V.2.7-86-99. Plugging cements. Test methods. Kiyev: State Committee for Construction, Architecture and Housing Policy.
25. Stryczek, S., Kremieniewski, M. (2023). Multi-component cements for sealing casing columns in boreholes. Buildings, 13(7), 1633.
26. Matschei, T., Lothenbach, B., Glasser, F. P. (2007). The role of calcium carbonate in cement hydration. Cement and Concrete Research, 37(4), 551-558.
27. Poongodi, K., Khan, A., Mushraf, M., et al. (2021). Strength properties of hybrid fibre reinforced quaternary blended high-performance concrete. Materials Today: Proceedings, 39, Part 1, 627-632.
28. Stavychnyi, Ye., Femiak, Ya., Vytyaz, O., Ziaja, Ja. (2024). Features of drilling and improving the quality of well cementing in conditions of abnormally low reservoir pressures. Nauka – Technika – Technologia: Seria Wydawnicza AGH, 9, 147-175.
29. Adil, G., Kevern, J. T., Mann, D. (2020). Influence of silica fume on mechanical and durability of pervious concrete. Construction and Building Materials, 247, 118453.
30. Tkaczewska, E., Malata, G. (2023). Properties of the cement, slag and fly ash mixture composition corresponding to CEM II/C-M and CEM VI. Materials Proceedings, 13(1), 11.
31. Barzgar, S., Tarik, M., Ludwig, C., Lothenbach, B. (2021) The effect of equilibration time on Al uptake in C-S-H. Cement and Concrete Research, 144, 106438.
32. Suleimanov, B. A., Veliyev, E. F. (2016). The effect of particle size distribution and the nano-sized additives on the quality of annulus isolation in well cementing. SOCAR Proceedings, 4, 4-10.
33. Taylor, H. F. W. (1990). Cement chemistry. London: Academic Press.
34. Tershak, В. А., Kovalchuk, M. B., Stavychnyi, Ye. M., et al. (2021). Isolation cementing of oil and gas wells of the Carpathian region. Exploration and Development of Oil and Gas Fields, 2(79), 7-15.
35. Lee, C. Y., Lee, H. K., Lee, K. M. (2003). Strength and microstructural characteristics of chemically activated fly ash-cement systems. Cement and Concrete Research, 33, 425–431. 
36. Ibrahimov, Kh. M., Hajiyev, A. A., Huseynova, N. I., Asadova, G. Sh. (2024). Consideration of the geological and technical condition of the reservoir and wellbore bottom zone in the selection of the cement composition applied to the production wellbore flow zone. Scientific Petroleum, 1, 36-43.
37. Cheng, X., Liu, K., Zhang, X., et al. (2018). Integrity changes of cement sheath due to contamination by drilling fluid. Advances in Cement Research, 30(2), 47-55.
38. Ajayi, T., Gupta, I. (2019). A review of reactive transport modeling in wellbore integrity problems. Journal of Petroleum Science and Engineering, 175, 785-803.
39. Li, J., Liu, J., Li, Z., et al. (2023). Influence laws for hydraulic sealing capacity in shale gas well cementing. SPE Drilling & Completion, 38(01), 120-130.
40. Ibrahimov, Kh. M., Hajiyev, A. A., Huseynova, N. I., Asadova, G. Sh. (2024). Consideration of the geological and technical condition of the reservoir and wellbore bottom zone in the selection of the cement composition applied to the production wellbore flow zone. Scientific Petroleum, 1, 36-43.
41. Wang, J., Pei, D., Lu, L., et al. (2024). Impacts of nano C-S-H-PCE on durability-related properties of portland cement composites with high-volume GGBFS. Construction and Building Materials, 449, 138547.
42. Zhang, B., Fang, L., Ding, Z., Li, M. (2024). The effect of modified basalt fiber on mechanical properties of oil well cement slurry. Case Studies in Construction Materials, 20, e03228.
43. Zou, Q., Wang, W., Wang, X., Liu, Y. (2025). Pore structure characteristics of cement stone modified by nano-MgO with different mass fractions. Powder Technology, 453, 120670.
44. Suleimanov, B. A., Veliyev, E. F., Shovgenov, A. D. (2022). Well cementing: fundamentals and practices. Moscow-Izhevsk: ICS.
45. Xiong, Q. X., Tong, L.-Y., Meftah, F., et al. (2024). Improved predictions of permeability properties in cement-based materials: A comparative study of pore size distribution-based models. Construction and Building Materials, 411, 133927.
46. Zheng, Y., Xie, Y., Sun, D., et al. (2024). Combined use of mullite and basalt fiber to inhibit the strength decline of oil well cement stone under alternating conditions of temperature rise and fall. Ceramics International, 50(13), Part A, 23472-23482.
47. Baltakys, K., Siauciunas, R. (2006). The influence of γ-Al₂O₃ and Na₂O on the formation of gyrolite in the stirring suspension. Journal of Materials Science, 41, 4799-4805.
48. Ohashi, Y. (1984). Polysynthetically-twinned structures of enstatite and wollastonite. Physics and Chemistry of Minerals, 10, 217-229.
49. Li, X., Chang, J. (2006). A novel hydrothermal route to the synthesis of xonotlite nanofibres and investigation on their bioactivity. Journal of Materials Science, 41, 4944-4947.
50. Hamilton, A., Hall, C. (2005) Physicochemical characterization of a hydrated calcium silicate board material. Journal of Building Physics, 29(1), 9-19.
51. Meducin, F., Bresson, B., Lequeux, N., de Noirfontaine, M.-N., Zanni, H. (2007). Calcium silicate hydrates investigated by solid-state high resolution 1H and 29Si nuclear magnetic resonance. Cement and Concrete Research, 37(5), 631-638.
52. Siauciunas, R., Baltakys, K. (2004). Formation of gyrolite during hydrothermal synthesis in the mixtures of CaO and amorphous SiO₂ or quartz. Cement and Concrete Research, 34(11), 2029-2036.
53. Stavychnyi, Ye., Rudyi, S., Femiak, Ya., et al. (2024). Influence of acid systems on bottomhole zone decolmatization and set cement stability. Physics and Chemistry of Solid State, 25(3), 664-674.
54. Stavychnyi, Ye., Femiak, Y., Vytyaz, O., et al. (2024). Research of cement stone degradability in difficult mining and geological conditions of Ukraine. Physics and Chemistry of Solid State, 25(4), 924-936.
55. Labus, M., Such, P. (2016). Microstructural characteristics of wellbore cement and formation rocks under sequestration conditions. Journal of Petroleum Science and Engineering, 138, 77-87.
56. Gong, P., Huang, K., Huang, Y., et al. (2024). Mechanism of graphene oxide inducing the orderly growth of CaCO₃ and C-S-H seed crystals in cement slurry-solid transition: Application in CCUS cementing. Construction and Building Materials, 449, 138268.
57. Ziaja, J., Stryczek, St., Jamrozik, A., et al. (2017). Sealing slurries limiting natural gas exhalations from the annular space of a wellbore. Przemysł Chemiczny, 5(96), 990-992.
58. Wang, Zh., Li, X., Wang, M., et al. (2024). The heterogeneous characteristics of the microstructure in cement stone under the effect of self-weight segregation. Research Square. https://doi.org/10.21203/rs.3.rs-4795580/v1
59. Lanka, S. T., Anak Moses, N. G., Suppiah, R. R., Maulianda, B. T. (2022). Physio-chemical interaction of ethylene-vinyl acetate copolymer on bonding ability in the cementing material used for oil and gas well. Petroleum Research, 7(3), 341-349.
60. Al Ramadan, M., Salehi, S., Kwatia, G., et al. (2019). Experimental investigation of well integrity: Annular gas migration in cement column. Journal of Petroleum Science and Engineering, 179, 126-135.
61. Lu, H., Zou, J., Zhang, T., et al. (2023). Study on a new cementitious material waterborne modified epoxy resin under sealed conditions for oil and gas wells. Construction and Building Materials, 387, 131588.
62. Kudapa, V. K. (2024) Investigation of carbon black nanoparticles on effectiveness of cementation in oil and gas well. Materials Today: Proceedings, 99, 162-169.
63. Veliyev, E. F., Aliyev, A. A. (2023), Design of a lightweight cementing material on basis of geopolymer and gas-forming agent. SOCAR Proceedings, 1, 17–22.
64. Kryzhanivskyi, Ye. I., Vytyaz, O. Yu., Tyrlych, V. V., et al. (2021). Evaluation of the conditions of drill pipes failure during tripping operations. SOCAR Proceedings, 1, 36–48.
65. Efendiyev, G. M., Moldabayeva, G. Z., Buktukov, N. S., Kuliyev, M. Y. (2024). With comprehensive cementing quality assessment and risk management system. SOCAR Proceedings, 4, 42-47.
66. Efendiyev, G. M., Moldabayeva, G. Z., Buktukov, N. S., Kuliyev, M. Y. (2024). Comprehensive cementing quality assessment and risk management system. SOCAR Proceedings, 4, 42-47.

The main causes of damage to the casing strings and excessive metal wear on well fastenings are: incompatibility of selected well designs with geological conditions of well construction; incompatibility of casing calculation methods with actual conditions of their operation in wells. Loss of integrity is characterised by the establishment of a link between the annular space and the wellbore as a result of damage to the column. The casing strings are worn out by the drilling tool to a certain extent. Based on the analysis, casing string damage is common in fields with complex geological and technical drilling conditions. The study is devoted to an urgent issue – determining the leakage interval of casing strings with calculations for estimating heat losses along the borehole during injection of hot liquid. The researcher proposed a fundamentally new method that had not previously been used in Turkmenistan. The essence of the method does not require the restoration of the thermal field after injection due to geotherms, on the contrary, stabilisation of the abnormal temperature is achieved during the injection process. When pumping hot liquid through an unpressurised area, part of the flow goes into the annular space. An area of mixing of hot and cold liquids is formed in the leaky zone, resulting in a temperature contrast. At the leakage level, the temperature difference becomes pronounced and can be detected using appropriate thermometric devices.

Keywords: casing string; drilling tool; defect; heated liquid; buffer; temperature anomaly.

Date submitted: 12.08.2025     Date accepted: 05.09.2025

References

1. Deryaev, A. R. (2024). Engineering aspects and improvement of well drilling technologies at the Altyguyi field. Machinery & Energetics, 15(2), 9-20.
2. Kunshin, A., Dvoynikov, M. (2018). Design and process engineering of slotted liner running in extended reach drilling wells. SPE-191520-18RPTC-MS. In: SPE Russian Petroleum Technology Conference, 15-17 October, Moscow, Russia.
3. Morenov, V., Leusheva, E., Martel, A. (2018). Investigation of the fractional composition effect of the carbonate weighting agents on the rheology of the clayless drilling mud. International Journal of Engineering: Basics, Applications and Aspects, 31(7), 1517-1525.
4. Mikhailov, A. Yu., Petrovsky, E. A., Pavlova, P. L., Strelkov, I. A. (2023). Improving the operational reliability of oil wells in the conditions of the Far North. Bulletin of the BSTU named after V.G. Shukhov, 7, 91-99.
5. Vromen, T. G. M. (2015). Control of stick-slip vibrations in drilling systems. PhD Thesis. Eindhoven: Eindhoven University of Technology.
6. Ziyatdinov, R. Z. (2019). A method for repairing a casing in a well. RU Patent 2715481.
7. Dzhaparov, A., Jepbarov, K. (1988). A method for determining the leakage interval of large-diameter casing strings. Patent SU1680965.
8. Khaled, M. S., Wang, N., Ashok, P., van Oort, E. (2023). Downhole heat management for drilling shallow and ultradeep high enthalpy geothermal wells. Geothermics, 107, 102604.
9. Rossi, E., Adams, B., Vogler, D., et al. (2020, August). Advanced drilling technologies to improve the economics of deep geo-resource utilization. In: 2nd Applied Energy Symposium: MIT A+B (MITAB 2020). ETH Zurich: Geothermal Energy &Geofluids.
10. Schneising, O., Buchwitz, M., Reuter, M., et al. (2020). Remote sensing of methane leakage from natural gas and petroleum systems revisited. Atmospheric Chemistry and Physics, 20(15), 9169-9182.
11. Quy, N. M., Trung, P. N. (2017). Impacts of condensate blockage and the effectiveness of technical solutions to improve well deliverability in gas condensate wells in Vietnam. SOCAR Proceedings, 1, 46-61.
12. Lu, C. F., Cai, C. X. (2019). Challenges and countermeasures for construction safety during the Sichuan-Tibet railway project. Engineering, 5(5), 833–838.
13. Bi, G., Li, G., Shen, Zh., et al. (2014). Design and rock breaking characteristic analysis of multi-jet bit on radial horizontal drilling. SOCAR Proceedings, 3, 22-29. 
14. Eren, T., Suicmez, V. S. (2020). Directional drilling positioning calculations. Journal of Natural Gas Science and Engineering, 73, 103081.
15. Ouadi, H., Mishani, S., Rasouli, V. (2023). Applications of underbalanced fishbone drilling for improved recovery and reduced carbon footprint in unconventional plays. Petroleum & Petrochemical Engineering Journal, 7(1), 000331.
16. Proselkov, Yu. М. (2017). Heat transfer in wells. Moscow: Nedra.
17. Hewitt, G. F., Shires, G. L., Bott, T. R. (1994). Process heat transfer. Boca Raton: CRC Press.
18. Sahu, D. K., Sen, P. K, Sahu, G., et al. (2015). A review on thermal insulation and its optimum thickness to reduce heat loss. International Journal of Innovative Science and Research Technology, 2(6), 2349–6010.
19. Yuan, J. (2018). Impact of insulation type and thickness on the dynamic thermal characteristics of an external wall structure. Sustainability, 10(8), 28–35.
20. Zhang, T., Yang, H. (2018). Optimal thickness determination of insulating air layers in building envelopes. Energy Procedia, 152, 444–449.

In order to a more precise understanding of the phenomenon of motion of fluid in non-homogeneous reservoirs modifications of classical Darcy law to include the memory effect which itself expressed by the fractional derivative in sense the Riemann-Liouville what break smoothness of solution. Therefore, classical solution of the main not exit. This fact hampers to application of the well-known numerical methods for finding approximation solution. In order to find of the weak solution in this paper, the new finite difference method find an approximate solution to the first boundary value problem for a partial differential equation of order 1 + α, (0 < α < 1), describing the flow of a single-phase fluid in a fractal medium is suggested. For his aim an auxiliary problem that is equivalent to the main problem in defined sense the solution of which smoothness of the solution the smoothness of which is one higher than the of the solution than of the main problem. The introduced auxiliary problem has more advantages. Using these advantages effective finite difference algorithms are proposed for finding an approximate solution to the main problem is proposed. Thus, the differential problem under consideration is reduced to a system of tridiagonal algebraic equations, which automatically satisfies the stability condition of the sweep method, and the solution of this system can be easily calculated. Introduction auxiliary problem permits us create a more higher order accuracy algorithms type Runge-Kutta with respect to time.

Keywords: flow in a fractal medium; fractional differential equation; finite differences representation of the fractional integrationin the Riemann-Liouville sense.

Date submitted: 13.05.2025     Date accepted: 20.08.2025

References

1. Afonin, A. A., Sukhinov, A. I. (2009). Mathematical models of geofiltration and geomigration in porous media with fractal structure. Izvestiya SFedU. Engineering Sciences, 97(8), 62-70.
2. Barabanov, V. L. (2016). Fractal model of the initial stage of capillary impregnation of rocks. Georesour, Geoenergy, Geopolit, 1(13), 1-16.
3. Belevtsov, N. S., Lukashchuk, S. Yu. (2020). Study of fractional-differential model of single-phase filtration with Riesz potential. Multiphase Systems, 15(1-2), 1-4.
4. Chang, A., Sun, H., Zhang, Y., et al. (2019). Spatial fractional Darcy’s law to quantify fluid flow in natural reservoirs. Physica A: Statistical Mechanics and its Applications, 519, 119-126.
5. Damián Adame, L., Gutiérrez-Torres, C. D.,C., Figueroa-Espinoza, B, et al. (2023). A mechanical picture of fractal Darcy’s law. Fractal and Fractional, 7(9), 1-12.
6. Gazizov, R. K., Lukashchuk, S. Y. (2017). Fractional differential approach to modelling filtration processes in complex inhomogeneous porous media. Vestnik Ufa State Aviation Technical University, 21(4), 104-112.
7. Kashchenko, N. M. (2010). Fractal model of filtration in conditions of drainage operation. Bulletin of the Immanuel Kant Baltic Federal University. Series: Physics, Mathematics, Technology, 4, 158-162.
8. Nigmatulin, R. R. (1986). The realization of the generalized transfer equation in a medium with fractal geometry.
   Physica Status Solidi, 133, 425-430.
9. Parovik, R. I. (2008). Modelling of radon (222Rn) transfer processes in environments with fractal structure and its flow into the surface layer of the atmosphere. Vestnik KRAUNTs. Series: Earth Sciences, 12(1),188-193.
10. Kilbas, A. A., Srivastava, H. M., Trujillo, J. J. (2006). Theory and applications of fractional differential equations. North-Holland: Elsevier.
11. Miller, K. S., Ross, B. (1993). An introduction to the fractional calculus and fractional differential equations. New York: A Wiley-Interscience Publication.
12. Oldham, K. B., Spanier, J. (1974). The fractional calculus. New York: Academic Press.
13. Podlubny, I. (1999). Fractional differential equations. San Diego: Academic Press.
14. Samko, S. G., Kilbas, A. A., Marichev, O. I. (1993) Fractional integrals and derivatives: Theory and applications. Montreux: Gordon and Breach Science Publishers.
15. Suleimanov, B. A., Abbasov, E. M., Efendieva, A. O. (2005). Stationary filtration in a fractal inhomogeneous porous medium. Journal of Engineering Physics and Thermophysics, 78(4), 832-834.
16. Ashyralyev, A. (2015). A survey of results in the theory of fractional spaces generated by positive operators. TWMS Journal of Pure and Applied Mathematics, 6(2), 129-157.
17. Aliyev, N. A., Rasulov, M. A., Sinsoysal, B. (2024). Study of the problem of one dimensional flow of homogenous fluids in fractal porous medium. Analysis and applied mathematics. Cham: Springer Nature.
18. Abasov, M. T., Rasulov, M. A., Ibrahimov, T. M., Ragimova, T. A. (1991). On a method of solving the cauchy problem for a first order nonlinear equation of hyperbolic type with a smooth initial condition. Soviet Mathematics. Doklady, 43(1), 150-153.
19. Rasulov, М. А. (1982). Numerical method for solving one parabolic equation with degeneracy. Differential Equations, 18(8), 1418-1427.
20. Rasulov, M. A. (2011). Conservation laws in the class of discontinuous functions. Ankara, Turkey: Seçkin Publishing House.

This study proposes an approach based on machine learning (ML) models as an alternative to conventional numerical reservoir simulation to predict liquid (oil and water) and oil flow rates of production wells in mature waterflooding oil fields. The proposed methodology uses commonly available measurement data of mature waterflooding oil fields, including the liquid and oil flow rates and perforation depths of production wells, together with the water flow rates of injection wells. Procedures for processing and constructing time series datasets suitable for large waterflooding oil fields with a complex history of well openings, well closures, and well perforation depth changes have been developed in the proposed method. The applicability of this proposal is demonstrated based on production data from wells from a large mature flooded oil field in Vietnam. The application shows that the ML models built according to the proposed methodology achieve good history matching and provide reliable forecasting results. Comparisons of performances with three different regression algorithms, including an artificial neural network (ANN) with one hidden layer, an ANN with two hidden layers, and the XGBoost algorithm, are also performed, with the conclusion being that the more complex regression algorithm is not always the best choice. 

Keywords: oil production; machine learning (ML) model; waterflooding oil field; regression algorithm.

Date submitted: 07.06.2025     Date accepted: 03.09.2025

References

1. Refunjol, B., Lake, L. W. (1997). Reservoir characterization based on tracer response and rank analysis of production and injection rates. In: Forth International Reservoir Characteristics Technical Conference, Houston, Texas, March 2-4.
2. Panda, M., Chopra, A. (1998). An integrated approach to estimate well interactions. SPE-39563-MS. In: SPE India Oil and Gas Conference and Exhibition, New Delhi, India, February 17-19. Society of Petroleum Engineers.
3. Albertoni, A., Lake, L. W. (2003). Inferring interwell connectivity only from well-rate fluctuations in waterfloods. SPE Reservoir Evaluation and Engineering, 6(1), 6-16.
4. Dinh, A. V., Tiab, D. (2008). Interpretation of interwell connectivity tests in a waterflood system. SPE-116144-MS. In: SPE Annual Technical Conference and Exhibition, Denver, Colorado, September 21-24. Society of Petroleum Engineers.
5. Lee, K. H., Ortega, A., Nejad, A. M., et al. (2009). A novel method for mapping fractures and high permeability channels in watefloods using injection and production rates. SPE-121353-MS. In: SPE Western Regional Meeting, San Jose, California, March 24-26. Society of Petroleum Engineers.
6. Trung, P. N., Duc, N. T. (2010). Optimizing injection and production allocation in multi-well water-flooding project using optimization algorithms and artificial neutral network. SOCAR Proceedings, 3, 17-22.
7. Zhao, H., Kang, Z., Sun, H., et al. (2016). An interwell connectivity inversion model for waterflooded multilayer reservoirs. Petroleum Exploration and Development, 43(1), 99-106.
8. Omar, I. A., Chen, Z., Khalifa, A. E. (2017). Predicating water-flooding performance into stratified reservoirs using a data driven proxy model. Journal of Petroleum and Gas Engineering, 8(7), 60-78.
9. Teixeira, A. F., Secchi, A. R. (2019). Machine learning models to support reservoir production optimization. IFACPapersOnLine, 52 (1), 498-501.
10. Negash, B. M., Yaw, A. D. (2020). Artificial neural network based production forecasting for a hydrocarbon reservoir under water injection. Petroleum Exploration and Development, 47(2), 383-392.
11. Zhang, R., Hu, J. (2021). Production performance forecasting method based on multivariate time series and vector autoregressive machine learning model for waterflooding reservoirs. Petroleum Exploration and Development, 48(1), 201-211.
12. Das, H. S., Shuvo, M. A. I., Abedin, A. A. (2023). Production forecast for a North sea oil field using artificial intelligence techniques. In: Proceedings of the Energy Conference 2023: National and Global Issues (ENCON23).
13. AlRassas, A.M. et al. (2024). Knowledge-based machine learning approaches to predict oil production rate in the oil reservoir. In: Lin, J. (Eds.) Proceedings of the International Field Exploration and Development Conference 2023. IFEDC 2023. Springer Series in Geomechanics and Geoengineering. Springer, Singapore.
14. He, D., Qu, Y., Sheng, G., et al. (2024). Oil production rate forecasting by SA-LSTM model in tight reservoirs. Lithosphere, 1, lithosphere_2023_197.
15. Schmidhuber, J. (2015). Deep learning in neural networks: An overview. Neural Networks, 61(1), 85-117.
16. Kumar, P. S., Behera, H. S., Kumari, A., et al. (2020). Advancement from neural networks to deep learning in software effort estimation: Perspective of two decades. Computer Science Review, 38, 100288.
17. Opitz, D. Maclin, R. (1999). Popular ensemble methods: An empirical study. Journal of Artificial Intelligence Research, 11, 169–198.
18. Polikar, R. (2006). Ensemble based systems in decision making. IEEE Circuits and Systems Magazine, 6(3), 21–45.
19. Breiman, L. (1996). Bagging predictors. Machine Learning, 24, 123–140.
20. Freund, Y. (1995). Boosting a weak learning algorithm by majority. Information and Computation, 121(2), 256–285.
21. Freund, Y., Schapire, R. E. (1997). A decision-theoretic generalization of on-line learning and an application to boosting. Journal of Computer and System Sciences, 55(1), 119–139.
22. Chen, T., Guestrin, C. (2016). Xgboost: A scalable tree boosting system. In: 22nd ACM SIGKDD international conference on knowledge discovery and data mining, San Francisco, CA, USA, August.
23. Rossum, G. V. (2009). The history of Python: A brief timeline of Python. http://python-history.blogspot.com/2009/01/brief-timeline-of-python.html
24. Mohbey, K. K., Bakariya, B. (2021). An introduction to Python programming: A practical approach. BPB Publications.
25. Sheela, K., Deepa, S. (2013). Review on methods to fix number of hidden neurons in neural networks. Mathematical Problems in Engineering, 6, 1-11.
26. Jain, A. (2015). XGBoost parameters tuning: A complete guide with Python codes. https://www.analyticsvidhya.com/blog/2016/03/complete-guide-parameter-tuning-xgboost-with-codes-python/

This article presents a comprehensive methodology for algorithmizing the selection and evaluation process of production well placement in mature oil fields, utilizing the combined power of geospatial analysis and machine learning techniques. As many mature fields approach the later stages of their production life cycle, challenges such as reservoir depletion, heterogeneity, and diminishing returns from conventional development methods necessitate the adoption of more data-driven, automated approaches. The integration of big data and advanced machine learning algorithms introduces new opportunities to optimize drilling strategies, minimize geological and operational uncertainties, and enhance the efficiency of hydrocarbon extraction. This study introduces a structured, automated approach divided into three key stages: identifying optimal drilling locations, forecasting production performance, and ranking candidate wells based on an extensive range of geological, petrophysical, and operational parameters. This methodology was tested on a complex multilayer oil field, using historical data from more than 3500 wells, and incorporated diverse datasets such as core analysis, production logs, seismic attributes, and pressure dynamics. Machine learning models demonstrated high predictive accuracy for key production metrics. The predictive accuracy of these models was confirmed by actual drilling results from operations conducted in 2024. The proposed algorithm demonstrated efficiency and accuracy comparable to traditional expert evaluations, but with significantly reduced time, human effort, and cost. The study highlights the transformative potential of integrating geospatial technologies with artificial intelligence in mature field development. It also provides insights into future improvements, including enhanced data fusion methods, real-time analytics, and model transparency.

Keywords: oil fields development; drilling; mature oil field; machine learning; well placement forecasting; candidates ranking.

Date submitted: 11.03.2025     Date accepted: 07.07.2025

References

1. Hirschfeldt, C. M., Bertomeu, F. D., Gerardo, L. (2017, March). Practical management in mature field operations. SPE-184937-MS. In: SPE Latin America and Caribbean Mature Fields Symposium, Salvador, Bahia, Brazil.
2. Grishchenko, V., Pozhitkova, S. S., Mukhametshin, V. S., Yakupov, R. F. (2021). Water cut forecast after downhole pumping equipment optimization based on displacement characteristics. SOCAR Proceedings, SI2, 143-151.
3. Wei, B. (2016). Well production prediction and visualization using data mining and Web GIS. Master's thesis. Calgary: University of Calgary.
4. Xu, X., Shao, Y., Fu, J., et al. (2013, March). The application of GIS in the digital oilfield construction. In: Proceedings of the 2nd International Conference on Computer Science and Electronics Engineering (ICCSEE 2013).
5. Khan, H., Srivastav, A., Kumar Mishra, A., et al. (2022, May). Machine learning methods for estimating permeability of a reservoir. International Journal of System Assurance Engineering and Management, 13, 2118–2131.
6. Ruizhi, Z., Cyrus, S., Ray, J. (2022). Machine learning for drilling applications: A review. Journal of Natural Gas Science and Engineering, 108, 104807.
7. Silva, V. C. (2019, October). Big data approach for assessing hydraulic interference between wells in not-controlled systems. SPE-29881-MS. In: The Offshore Technology Conference Brazil, Rio de Janeiro, Brazil.
8. Salehi, A., Arslan, I., Deng, L., et al. (2021, September). A data-driven workflow for identifying optimum horizontal subsurface targets. SPE-205837-MS. In: The SPE Annual Technical Conference and Exhibition, Dubai, UAE.
9. Alvi, A., Tilke, P., Bogush, A., et al. (2012, December). Delivering optimal brownfield development strategies: use of multi-constrained optimisation combined with fast semi-analytical and numerical simulators. SPE-163337-MS. In: The SPE Kuwait International Petroleum Conference and Exhibition, Kuwait City, Kuwait.
10. Kolesov, V., Kurganov, D. (2019). Well ranking for in-fill drilling using machine learning with production and geological data. Vestnik of Samara State Technical University (Technical Sciences Series), 1(61), 6-19.
11. Tadjer, A., Hong, A., Reidar, B. (2022). Bayesian deep decline curve analysis: a new approach for well oil production modeling and forecasting. SPE Reservoir Evaluation & Engineering, 25, 568–582.
12. Zhetruov, Z. T., Shayakhmet, K. N., Karsybayev, K. K., et al. (2022). Application of proxy models for oil reservoirs performance prediction. Kazakhstan Journal for Oil & Gas Industry, 4(2), 47-56.
13. Kullawan, K., Bratvold, R., Bickel, J. E. (2013, October). A decision analytic approach to geosteering operations. SPE-167433-MS. In: The SPE Middle East Intelligent Energy Conference and Exhibition, Manama, Bahrain.
14. Beken, A. A., Ibrayev, A. Y., Zhetruov, Z. T., et al. (2024). Automatic selection of sites for drilling candidate injection wells. Kazakhstan Journal for Oil & Gas Industry, 6(1), 74-86. 
15. Ibrayev, A. Y., Kamaridenova, G. S., Baluanov, B. A., Yelemessov, A. S. (2023). New well water cut prediction using machine learning. Kazakhstan Journal for Oil & Gas Industry, 5(3), 20–34.
16. Hubert, M., Vandervieren, E. (2008). An adjusted boxplot for skewed distributions. Computational Statistics & Data Analysis, 52(12), 5186–5201.
17. Müller, A.C., Guido, S. (2016). Introduction to machine learning with Python. USA: O'Reilly Media, Inc.
18. Percival, H., Gregory, B. (2020). Architecture patterns with Python. USA: O'Reilly Media, Inc.

One of the indicators of UGS efficiency is the volume of active gas in the storage facility. Another method for increasing the volume of gas stored in UGS facilities is proposed, based on improving the quality of stored natural gas with reduced moisture content by drying it before pumping it into the reservoir. It has been noted that the current gas injection process into the UGS (Underground Gas Storage) is inefficient, as only 90% of the pore space is utilized and 10% of the capacity of compressor stations is spent on pumping unnecessary water vapor, which also leads to excessive consumption of fuel gas, energy, and materials. The gas injection and extraction indicators are analyzed using the example of the Galmaz UGS facility, a scheme for using a gas drying unit in the gas injection scheme is developed. It is proposed to pump according to the scheme the main gas pipeline - gas metering unit - gas drying unit - compressor stations - manifold block - wells. Due to the use of the proposed technological process, it is possible to reduce the injection of moisture into the reservoir by more than 6 tons per season, which will allow for a new quality state of the stored natural gas to be achieved within 2-3 years. As a result of the increase in the share of combustible components in the reservoir, an increase in the volume of active gas in the UGS can be ensured.

Keywords: natural gas; underground gas storage; gas drying; compressor station; moisture content; dew point.

Date submitted: 15.05.2025     Date accepted: 02.09.2025

References

1. Vishnyakov, V. V., Suleimanov, B. A., Salmanov, A. V., Zeynalov, E. B. (2019). Primer on enhanced oil recovery. Gulf Professional Publishing.
2. Zhang, J., Fang, F., Lin, W., et al. (2020). Research on injection-production capability and seepage characteristics of multi-cycle operation of underground gas storage in gas field—case study of the Wen 23 gas storage. Energies, 13, 3829.
3. Barenblatt, G. I., Mamedov, Yu. G., Mirzadzhanzade, A. Kh., Shvetsov, I. A. (1973). Nonequilibrium effects in the filtration of viscoelastic liquids. Fluid Dynamics, 8(5), 742–748.
4. Suleimanov, B. A. (1997). Slip effect during filtration of gassed liquid. Colloid Journal, 59(6), 749 – 753.
5. Jamalbayov, M. A., Valiyev, N. A., Ibrahimov, Kh. M., et al. (2024). Energy and efficiency optimization in sucker-rod pumping using discrete-imitation modeling concept: application to well operations in the Bibi-Eibat field of Azerbaijan. SOCAR Proceedings, SI1, 95–101.
6. Suleimanov, B. A., Azizov, F., Abbasov, E. M. (1998). Specific features of the gas-liquid mixture filtration. Acta Mechanica, 130(1-2), 121–133.
7. Magerramov, N. Kh., Mirzadzhanzade, A. Kh. (1960). Filtration of gas-condensate mixtures in a porous medium. Journal of Applied Mathematics and Mechanics, 6(24), 1656–1664.
8. Pashayev, N. V. (2024). Development of petrophysıcal modelıng based on effectıve porosıty and phase permeabılıtıes of reservoırs (Bınagadı oıl fıeld as a case study). ANAS Transactions. Earth Sciences, 1, 171–179.
9. Peng, Y., Lı, Y., Zhu, G., et al. (2019). Mechanisms and experimental research of ion-matched waterflooding to enhance oil recovery in carbonate reservoirs: A case of Cretaceous limestone reservoirs in Halfaya Oilfield, Middle East. Petroleum Exploration and Development, 46(6), 1231–1241.
10. Suleimanov, B. A. (2011). Sand plug washing with gassy fluids. SOCAR Proceedings, 1, 30–36.
11. Suleimanov, B. A., Rzayeva, S. J., Akberova, A. F., Akhmedova, U. T. (2021). Deep diversion strategy of the displacement front during oil reservoirs watering. SOCAR Proceedings, 4, 33–42.
12. Bagirov, A. N., Baghirov, Sh. A. (2020). Application of technological transfer method in modeling compressor stations of underground gas storages. Azerbaijan Oil Industry, 4, 29-32.
13. Iskenderov, E. Kh., Baghirov, A. N., Baghirov, Sh. A., Ismailova, P. Sh. (2022). Development of new technological processes based on supersonic flow of natural gas. SOCAR Proceedings, 4, 117-123.
14. Iskandarov, E. K., Baghirov, A. N., Shikhiyeva, L. M., Aliyev, I. (2024). Method for assessing the hydrate formation from a mixture of natural gas flows of varying degrees of moisture content. Nafta-Gaz, 1, 39–44.
15. Ismailov, G. G., Alakparov, Y. Z., Ismailov, R. A. (2022). About rationale for the selection of the cooling capacity of the turbodetander unit in the process of gas preparation. SOCAR Proceedings, 4, 130–133
16. Ismayilov, G. G., Ismailov, R. A., Babirov, X. N. (2022). Investigation of the dynamics of particle settling during separation condensing gases. SOCAR Proceedings, SI1, 1–6.
17. Iskandarov, E. Kh. (2024). Study of structural changes in multifaceted gas pipelines. SOCAR Proceedings, 4, 117–122.
18. Iskandarov, E. Kh., Novruzova, S. H. (2024). Diagnostics of the technological condition of gas pipelines based on the composition of the transported gas mixtures. Nafta-Gaz, 80(6), 371–375.
19. Ismayilov, G. G., Ismailov, R. A., Ahmadzada, F. N. (2021). Diagnosing of the presence of liquid inclusions in the gas pipelines. SOCAR Proceedings, SI1, 156–161.
20. Ismayilov, G. G., Iskanderov, E. Kh., Fataliyev, V. M., et al. (2023). Some aspects for improving the efficiency of the development of gas condensate resources in marine conditions. SOCAR Proceedings, 4, 99–105.
21. Chang, Y., Huang, B., Xu, Q., et al. (2025). Effect of the operation pressure on severe slugging in a gas-liquid twophase flow in the pipeline-riser system. Ocean Engineering, 317(5), 120071.
22. Zeynalova, G., Ismayilov, G. (2023). Dıagnostıcs of rısky multıphase flow zones ın oıl pıpelınes. Reliability: Theory and Applications, 18 (Special Issue 5), 283–287.
23. Dadash-Zade, M. A., Aliyev, I. N. (2022). Rheological properties of elastic-visco-plastic liquid. Nafta-Gaz, 78(11), 801–804.
24. Kelbaliev, G. I., Rasulov, S. R., Mustafaeva, G. R. (2018). Modeling of phenomena of drop coalescence in oil emulsion breaking processes. Chemistry and Technology of Fuels and Oils, 54(2), 158–165.
25. Suleimanov, B. A., Veliyev, E. F., Vishnyakov, V. V. (2022). Nanocolloids for petroleum engineering: Fundamentals and practices. John Wiley & Sons.
26. Suleimanov, B. A., Rzayeva, S. J., Akberova, A. F., Akhmedova, U. T. (2022). Self-foamed biosystem for deep reservoir conformance control. Petroleum Science and Technology, 40(20), 2450-2467.
27. Suleimanov, B. A., Rzayeva, S. J., Akberova, A. F. (2021). Self-gasified biosystems for enhanced oil recovery.
    International Journal of Modern Physics B, 35(27), 2150274.
28. Yushi, D., Carlos, A., Haijing, G., et al. (2022). A hybrid modeling approach to estimate liquid entrainment fraction and its uncertainty. Computers and Chemical Engineering, 162, 107796.
29. Suleimanov, B. A. (2011). Mechanism of slip effect in gassed liquid flow. Colloid Journal, 73(6), 846–855.
30. Mirzadzhanzade, A. Kh., Bokserman, A. A., Chubanov, O. V., Suleimanov, A. A. (2004). About approximation method of forecasting efficiency of new field development technologies. Oil Industry, 2, 120–121.
31. Sattarov, R. M., Ismailov, R. A. (2001). Some problems of mechanics of non-equilibrium gases flowing through visco-elastic ducts. Mekhanika i Mashinostroyeniye, 1, 12-14.
32. Lin, Z., Junming, F., Jia, Z., et al. (2014). Formula calculation methods of water content in sweet natural gas and their adaptability analysis. Natural Gas Industry B, 1, 144-149. 
33. Gurbanov, H. R., Gasimzade, A. V. (2023). Study on efficiency of new multifunctional compositions for preparation of oil for transportation. Voprosy Khimii i Khimicheskoi Tekhnologii, 4, 41–50.
34. Mohammadi, A. H., Chapoy, A., Richon, D., Tohidi, B. (2004). Experimental measurement and thermodynamic modeling of water content in methane and ethane systems. Industrial & Engineering Chemistry Research, 43(22), 7148e62.
35. Diogo, A. F., Moura, P. M. (2025). Experimental study of two and three-phase steady flows in inclined rising pipes. Experimental Thermal and Fluid Science, 165, 111430.
36. Wang, X., Ismayilov, G., Iskandarov, E., et al. (2025). Study of specific problems arising in the blending processes of crude oil (based on the examples of azerbaijan oils). Processes, 13, 1500.
37. Aslanov, L. F., Aslanov, F. L. (2024). Choosing an effective design solution for fixing offshore hydro-technical structures to shelf ground. In: Çiner, A., et al. Recent Research on Geotechnical Engineering, Remote Sensing, Geophysics and Earthquake Seismology. MedGU 2021. Advances in Science, Technology & Innovation. Springer, Cham.
38. Aslanov, L. F., Aslanli, U. L. (2024). Determination of load-bearing capacity of piles used in stationary offshore platforms. SOCAR Proceedings, 1, 116–123.
39. Bazaev, A. R., Bazaev, E. A. (2018). Volumetric properties of natural gas occurring in formations under conditions of high temperatures and pressures. Scientific and Technical Collection «Gas Scıence News», 5(37), 30-37.
40. Gurbanov, R. S., Abdinov, E. T., Bakhtiyarov, S. I. (2004). Rheological flows in channels with complex geometry and porous medium. In: Proceedings of the ASME 2004 Heat Transfer/Fluids Engineering Summer Conference, Vol. 1, Charlotte, North Carolina, USA, July 11–15.
41. Jarni, H. H., Wan Azmi, W. N. S., Mohd Razlan, M. R., Noor, A. M. (2023). Effect of the water condensation rate with the presence of gas condensate in the wet gas pipeline. Key Engineering Materials, 939, 65-74.
42. Schouten, J. A., Janssen-van Rosmalen, R., Michels, J. P. J. (2005). Condensation in gas transmission pipelines. International Journal of Hydrogen Energy, 30(6), 661-668.
43. Ismayilov, G. G., Ismayilova, F. B., Musaev, S. F. (2021). Forecasting the viscosity properties of water-oil systems. SOCAR Proceedings, SI1, 109–115.

In recent years, when constructing and performing major repairs of main pipelines in swamps, underwater sea and river crossings, concrete-coated pipes are used to prevent them from floating up. Experience in their operation in difficult natural and climatic conditions has shown that concrete-coated pipes float up before gas is supplied. The purpose of the research is to establish the influence of operating conditions and design features on the floating up of a gas pipeline in a swamp. To simulate the stress-strain state (SSS) of a gas pipeline in a swamp, a one-dimensional rod system is used, consisting of rods with tubular cross-sections and junctions of these rods. Geometrical and physical relationships, equilibrium equations for the rod are transformed into a normal system of nonlinear ordinary differential equations. When integrating this system, the Godunov orthogonal sweep method is used. Systems of algebraic equilibrium equations are composed at the junction nodes of the rods; their solutions are found by the Gauss method. Computer modeling of the gas pipeline SDS in a swamp before gas supply established the influence of the specific gravity of swamp water on its floating, depending on the concentration of mineral salts dissolved in it and the remains of decomposition of plant origin, the length of the flooded underwater part. Recommendations are made to change the design of the concrete-coated pipe to prevent its floating (geometric dimensions of the concrete shell and steel pipe).

Keywords: gas pipeline; soil; swamp; concrete-coated pipe; flooding.

Date submitted: 08.04.2025     Date accepted: 29.07.2025

References

1. Dimov, L. A., Bogushevskaya, E. M. (2010). Main pipelines in swampy and flooded areas. Moscow: Gornaya Kniga Publishing House, Moscow State Mining University Publishing House.
2. Bykov, L. I., Mustafin, F. M., Rafikov, S. K., et al. (2011). Typical calculations in the design, construction and repair of gas and oil pipelines. St. Petersburg: Nedra.
3. Sharygin, V. M., Yakovlev, A. Ya. (2009). Laying and ballasting gas pipelines in difficult conditions. Moscow: CenterLitNeftegaz.
4. Vasiliev, G. G., Goryainov, Yu. A., Saksagansky, A. I. (2012). Advantages and disadvantages of modern approaches to ballasting underwater crossings. NGS, 1, 30-37.
5. Islamgaleeva, L. F., Zaripov, R. M. (2011). Influence of the degree of soil waterlogging in adjacent underground sections on the stress-strain state of an underwater gas pipeline. Oil and Gas Business, 6, 116-129.
6. Kozhaeva, K. V., Zhdanov, R. R., Azmetov, H. A. (2022). Study of the influence of longitudinal force on the intensity of underwater pipeline ballasting. Problems of Collection, Preparation and Transportation of Oil and Oil Products, 1(335), 66-77. 
7. (2005). SNiP 2.05.06-85*. Main pipelines. Moscow: FSUE CPP.
8. Ainbinder, A. B., Kamershteyn, A. G. (1982). Calculation of main pipelines for strength and stability. Reference manual. Moscow: Nedra.
9. Shammazov, A. M., Zaripov, R. M., Chichelov, V. A., Korobkov, G. E. (2006). Calculation and ensuring the strength of pipelines in complex engineering and geological conditions. Vol.2. Assessment and ensuring the strength of pipelines. Moscow: Publishing house «Inter».
10. Lapteva, T. I., Mansurov, M. N. (2018). Development of methods to ensure the operability of offshore gas pipelines in the conditions of the Arctic shelf. Collection of scientific papers of the expert engineering company «EKSIKOM» No. 1 «Reliability and safety of operation of the linear section of main gas and oil pipelines». Moscow: Russian State University of Oil and Gas.
11. Lapteva, T. I. (2018). Improving the safe operation of offshore pipelines in complex engineering and geological conditions of the Arctic shelf. Oil. Gas. Innovations, 5, 63-65.
12. Lapteva, T. I. (2018). Operational reliability of offshore pipelines in complex engineering and geological conditions of the continental shelf of Russia. Occupational Safety in Industry, 1, 30-34.
13. Lapteva, T. I., Mansurov, M. N., Shabarchina, M. V., Kopaeva, L. A. (2018). Offshore pipelines in the transit zone of the Arctic shelf. Ensuring operability. Oil&Gas Journal Russia, 9, 78-84.
14. An, E. V., Rashidov, T. R. (2015). Seismodynamics of underground pipelines interacting with water-saturated fine soil. Bulletin of the Russian Academy of Sciences. Solid State Mechanics, 3, 89-104.
15. Shestov, A. S., Marchenko, A. V., Ogorodov, S. A. (2011). Mathematical modeling of the impact of ice formations on the bottom of the Baydaratskaya Bay of the Kara Sea. Proceedings of the Central Research Institute named after academician A .N. Krylov, 5, 105–118.
16. Zaripov, R. M., Masalimov, R. B. (2023). Numerical modeling of the stress-strain state of an underwater offshore gas pipeline taking into account soil liquefaction and operating parameters. Bulletin of the Russian Academy of Sciences. Solid Mechanics, 4, 152–166.
17. Zaripov, R. M., Masalimov, R. B. (2023). Use of compensators in the underwater section of an offshore gas pipeline to prevent its surfacing. Bulletin of the Tomsk Polytechnic University. Georesources Engineering, 334(2), 196–205.
18. Zaripov, R. M., Bakhtizin, R. N., Masalimov, R. B. (2023). Study of the influence of changes in soil conditions and operating parameters of the underwater section of the offshore oil pipeline on its possible surfacing. Oil Industry, 6, 83–87.
19. Zaripov, R. M., Bakhtizin, R. N., Masalimov, R. B. (2023). Stress-strain state of the underwater gas pipeline and the installation of expansion joints designed to prevent its floating. SOCAR Proceedings, SI2, 1-11.
20. Bi, K., Hao, H. (2016). Using pipe-in-pipe systems for subsea pipeline vibration control. Engineering Structures, 109, 75–84.
21. Davaripour, F., Quinton, B.W.T., Pike, K. (2021). Effect of damage progression on the plastic capacity of a subsea pipeline. Ocean Engineering, 234, 109118.
22. Palmer, A. C., King, R. A. (2004). Subsea pipeline engineering. Oklahoma: PWC.
23. Hong, Z., Liu, R., Liu, W., Yan, S. (2015). Study on lateral buckling characteristics of a submarine pipeline with a single arch symmetric initial imperfection. Ocean Engineering, 108, 21-32.
24. Cheng, A., Chen, N.-Z. (2017). Corrosion fatigue crack growth modelling for subsea pipeline steels. Ocean Engineering, 142, 10-19.
25. Wang, Z., Tang, Y. (2020). Study on symmetric buckling mode triggered by dual distributed buoyancy sections for subsea pipelines. Ocean Engineering, 216, 108019.
26. Chen, Y., Dong, S., Zang, Zh., et al. (2021). Buckling analysis of subsea pipeline with idealized corrosion defects using homotopy analysis method. Ocean Engineering, 234, 108865.
27. Peek, R., Yun, H. (2007). Flotation to trigger lateral buckles in pipelines on a flat seabed. Journal of Engineering Mechanics, 4, 442-451.
28. Zhao, E., Qu, K., Mu, L., et al. (2019). Numerical Study on the hydrodynamic characteristics of submarine pipelines under the impact of real-world tsunami-like waves. Water, 11(2), 221.
29. Huang, B., Liu, J., Lin, P., Ling, D. (2014). Uplifting behavior of shallow buried pipe in liquefiable soil by dynamic centrifuge test. The Scientific World Journal, Article ID 838546. 
30. (2007). ASME B31.8-2007. Gas transmission and distribution piping systems. The American Society of Mechanical Engineers.
31. (1988). DNV-RP-E305. On-Bottom stability of submarine pipelines. Veritas Offshore Technology and Services.
32. Chee, J., Walker, A., White, D. (2018). Controlling lateral buckling of subsea pipeline with sinusoidal shape pre-deformation. Ocean Engineering, 151, 170–190.
33. Chee, J., Walker, A., White, D., et al. (2019). Experimental study on dynamic interaction between pipe and rollers in deep S-lay. Ocean Engineering, 175, 188–196.
34. Xiao, Y. Y., Wu, Z. W., Wang, T. C., et al. (2023). Experimental and numerical investigation on hydrodynamic behavior of a long-curved pipeline system with multiple floating bodies in immersion construction. Ocean Engineering, 270, 113629.
35. Wang, Z., Chen, Y., Gao, Q., Li, F. (2023). An analytical method for mechanical analysis of offshore pipelines during lifting operation. Materials, 16, 6685.
36. Wang, Z., Tang, Y., Guedes, S. C. (2021). Imperfection study on lateral thermal buckling of subsea pipeline triggered by a distributed buoyancy section. Marine Structures, 76, 102916.
37. Lu, Z. Q., Zhang, K. K., Ding, H., Chen, L. Q. (2020). Nonlinear vibration effects on the fatigue life of fluid-conveying pipes composed of axially functionally graded materials. Nonlinear Dynamics, 100(2), 1091–1104.
38. Mao, X., Ding, H., Chen, L. (2021). Bending vibration control of pipes conveying fluids by nonlinear torsional absorbers at the boundary. Science China Technological Sciences, 64, 1690–1704.
39. Limarchenko, V. O., Limarchenko, O. S., Sapon, N. N. (2020). Dynamics of a pipeline with a liquid on a rotating base. International Applied Mechanics, 56, 351–357.
40. Huayuan, M., Long, Y., Zhong, M., et al. (2019). Study on ground vibration mode of physical explosion of high pressure natural gas pipeline. Acoustical Physics, 65, 583–592.
41. Li, S., Karney, B. W., Liu, G. (2015). FSI research in pipeline systems – A review of the literature. Journal of Fluids and Structures, 57, 277–297.
42. Korobkov, G. E., Zaripov, R. M., Shammazov, I. A. (2009). Numerical modeling of the stress-strain state and stability of pipelines and tanks under complicated operating conditions. St. Petersburg: Nedra Publishing House.
43. Myachenkov, V. I., Maltsev, V. P. (1984). Methods and algorithms for calculating spatial structures on an ES computer. Moscow: Mashinostroenie.
44. Ilgamov, M. A. (2022). Model of underwater pipeline flotation. Doklady Physics, 67, 123-127.

The startup process of high-speed centrifugal pumps (impeller speeds >3000 RPM) exhibits pronounced nonlinear characteristics, presenting significant challenges for achieving rapid and stable transient operation. To address limitations in conventional control strategies – including substantial speed overshoot, sluggish convergence, poor stability, and pronounced chattering observed in traditional proportional-integral-derivative (PID) controllers and sliding mode controllers (SMC) – this study proposes a novel fuzzy sliding mode controller (FSMC) incorporating an optimized reaching law. First, a rigorous nonlinear mathematical model integrating motor-pump dynamics was established for the startup phase. A pioneering sliding mode reaching law was designed using a nonlinear power combination function and a hyperbolic tangent function, with Lyapunov stability analysis formally verifying asymptotic convergence. Subsequently, a fuzzy inference system dynamically adjusted the reaching law coefficients in real-time, optimizing transient performance while suppressing chattering. Comprehensive simulations were conducted in Simulink/MATLAB using parameters from a Q5H26 high-speed centrifugal pump system. Comparative results demonstrate that the proposed FSMC achieves a 70.6% reduction in speed overshoot versus PID and eliminates overshoot entirely compared to conventional SMC. The controller attains rapid dynamic response during startup, converging to steady-state operation (733 rad/s) within 0.25 seconds with negligible overshoot. Furthermore, it exhibits exceptional chattering attenuation and maintains robust disturbance rejection, limiting speed deviation to 1.3% under a 10N step load disturbance—outperforming PID, SMC, and improved SMC (ISMC) alternatives. These advancements validate the FSMC’s efficacy in enhancing control precision, response speed, and operational resilience for high-speed centrifugal pump startups. 

Keywords: high-speed centrifugal pump; startup process; fuzzy control; novel approaching law.

Date submitted: 11.03.2025     Date accepted: 12.08.2025

References

1. Lobanoff, V. S., Ross, R. R. (2013). Centrifugal pumps: design and application. Gulf Professional Publishing.
2. Kelly, J. H. (2010). Understand the fundamentals of centrifugal pumps. Chemical Engineering Progress, 106(10), 22-28.
3. Shah, S. R., Jain, S. V., Patel, R. N., Lakhera, V. J. (2013). CFD for centrifugal pumps: a review of the state-of-the-art. Procedia Engineering, 51, 715-720.
4. Ayad, A. F., Abdalla, H. M., Aly, A. A. E. A. (2015). Effect of semi-open impeller side clearance on the centrifugal pump performance using CFD. Aerospace Science and Technology, 47, 247-255.
5. Shojaeefard, M. H., Hosseini, S. E., Zare, J. (2019). CFD simulation and Pareto-based multi-objective shape optimization of the centrifugal pump inducer applying GMDH neural network, modified NSGA-II, and TOPSIS. Structural and Multidisciplinary Optimization, 60(4), 1509-1525.
6. Yan, X., Zhang, F., Zheng, Y., et al. (2024). Numerical investigation of hydraulic instability of pump-turbines in fast pump-to-turbine transition. Journal of Energy Storage, 96, 112731.
7. Wang, C., Zhang, Y., Zhu, J., et al. (2021). Effect of cavitation and free-gas entrainment on the hydraulic performance of a centrifugal pump. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 235(3), 440-453.
8. Li, Y., Guo, D., Li, X. (2019). The effect of startup modes on a vacuum cam pump. Vacuum, 166, 170-177.
9. Tsukamoto, H., Ohashi, H. (1982). Transient characteristics of a centrifugal pump during starting period. Journal of Fluids Engineering, 104(1), 6-13.
10. Chalghoum, I., Elaoud, S., Akrout, M., Taieb, E. H. (2016). Transient behavior of a centrifugal pump during starting period. Applied Acoustics, 109, 82-89.
11. Thanapandi, P., Prasad, R. (1995). Centrifugal pump transient characteristics and analysis using the method of characteristics. International Journal of Mechanical Sciences, 37(1), 77-89.
12. Dazin, A., Caignaert, G., Bois, G. (2007). Transient behavior of turbomachineries: applications to radial flow pump startups. Journal of Fluids Engineering, 129(11), 1436-1444.
13. Wu, D., Wang, L., Hao, Z., et al. (2010). Experimental study on hydrodynamic performance of a cavitating centrifugal pump during transient operation. Journal of Mechanical Science and Technology, 24, 575-582.
14. Diaz, C., Ruiz, F., Patino, D. (2017). Modeling and control of water booster pressure systems as flexible loads for demand response. Applied Energy, 204, 106-116.
15. Xu, W., Wei, D., Lei, C. (2016, December). Control for the centrifugal pump in the simulation platform of power plants. In: 2016 International conference on industrial informatics-computing technology, intelligent technology, industrial information integration (ICIICII), Wuhan, China.
16. Brezina, T., Kovar, J., Hejc, T. (2011, June). Modeling and control of system with pump and pipeline by pole placement method. In: 14th International Conference Mechatronika, Trencianske Teplice, Slovakia.
17. Arun, S. V., Subramaniam, U., Padmanaban, S., et al. (2019, April). Investigation for performances comparison PI, adaptive PI, fuzzy speed control induction motor for centrifugal pumping application. In: 2019 IEEE 13th International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), Sonderborg, Denmark.
18. Wang, Y., Zhang, H., Han, Z., Ni, X. (2021). Optimization design of centrifugal pump flow control system based on adaptive control. Processes, 9(9), 1538.
19. Gevorkov, L., Rassõlkin, A., Kallaste, A., Vaimann, T. (2018, January). Simulink based model for flow control of a centrifugal pumping system. In: 2018 25th International Workshop on Electric Drives: Optimization in Control of Electric Drives (IWED), Moscow, Russia.
20. Caba, S., Lepper, M., Liu, S. (2016, September). Nonlinear controller and observer design for centrifugal pumps. In: 2016 IEEE Conference on Control Applications (CCA), Buenos Aires, Argentina.
21. Hatem= Bellahsene, N. R. (2024). Fuzzy based supervision approach in the event of rotational speed inversion in an induction motor. Acta Mechanica et Automatica, 18(1), 68-76.
22. Bordeasu, D., Prostean, O., Filip, I., Vasar, C. (2023). Adaptive control strategy for a pumping system using a variable frequency drive. Machines, 11(7), 688.
23. Jordanou, J. P., Osnes, I., Hernes, S. B., et al. (2022). Nonlinear model predictive control of electrical submersible pumps based on echo state networks. Advanced Engineering Informatics, 52, 101553.
24. Jaimes Saavedra, C. F., Roa Prada, S., Maradey Lázaro, J. G. (2016, November). Modeling and optimal control of a variable-speed centrifugal pump with a pipeline. In: Proceedings of the ASME 2016 International Mechanical Engineering Congress and Exposition. Volume 4A: Dynamics, Vibration, and Control. Phoenix, Arizona, USA.
25. Yun, L., Bin, L., Jie, F., et al. (2020). Research on the transient hydraulic characteristics of multistage centrifugal pump during start-up process. Frontiers in Energy Research, 8, 76.
26. Guang, W. L., Liu, Q., Jin, F. Y., et al. (2024). Analysis of clearance flow of a fuel pump based on dynamical mode decomposition. Journal of Hydrodynamics, 36(4), 781-795.
27. Spurgeon, S. K. (2008). Sliding mode observers: a survey. International Journal of Systems Science, 39(8), 751-764.
28. Jain, R. K., Barry, V. R., Gadiraju, H. K. V. (2021). Model-based design and sliding mode control approach for two-stage water pumping system with reduced sensors. IEEE Journal of Emerging and Selected Topics in Power Electronics, 10(4), 3940-3949.
29. Mohd Zaihidee, F., Mekhilef, S., Mubin, M. (2019). Robust speed control of PMSM using sliding mode control (SMC)—A review. Energies, 12(9), 1669. 
30. Janevska, G. (2013, September). Mathematical modeling of pump system. In: Electronic International Interdisciplinary Conference, Vol. 2, Zilina, Slovak Republic.
31. Hou, H., Yu, X., Xu, L., et al. (2019). Finite-time continuous terminal sliding mode control of servo motor systems. IEEE Transactions on Industrial Electronics, 67(7), 5647-5656.
32. Sun, C., Dong, X., Wang, M., Li, J. (2022). Sliding mode control of electro-hydraulic position servo system based on adaptive reaching law. Applied Sciences, 12(14), 6897.
33. Wan, L., Wang, Z. (2024). Integral sliding mode control of TS fuzzy systems via a fuzzy triggering mechanism. IEEE Access, 12, 17748-17759.
34. Su, X., Wen, Y., Shi, P., et al. (2019). Event-triggered fuzzy control for nonlinear systems via sliding mode approach. IEEE Transactions on Fuzzy Systems, 29(2), 336-344.
35. Selvachandran, G., Quek, S. G., Lan, L. T. H., et al. (2019). A new design of mamdani complex fuzzy inference system for multiattribute decision making problems. IEEE Transactions on Fuzzy Systems, 29(4), 716-730.

Post-tensioned hollow circular concrete members are widely utilized in offshore platforms supporting oil and gas production, marine transport operations, and port facilities. To overcome the limitations associated with transporting and assembling massive monolithic elements, segmental construction methods are increasingly adopted due to their efficiency in prefabrication, modularity, and offshore installation. However, the shear transfer at intersegmental joints constitutes a critical design concern, as it governs both the structural reliability and long-term performance of such systems. The accurate modeling of cracking behavior is fundamental for predicting shear resistance in segmental post-tensioned hollow circular members. Crack orientation, rotation, and propagation significantly affect shear stiffness degradation, force transfer mechanisms, and the ultimate load-carrying capacity. This study evaluates the performance of fixed and rotating crack models using nonlinear finite element simulations. Four-point bending tests are numerically reproduced to examine crack initiation and shear redistribution within the segmental joints. The analysis framework allows for a detailed comparison of shear stress trajectories, interface slip, and ultimate resistance under combined bending–shear actions. Results demonstrate that the rotating crack model captures post-cracking shear redistribution with higher accuracy, while the fixed crack approach provides computational robustness but tends to underestimate ultimate shear strength. These findings highlight the substantial influence of crack modeling strategies on the prediction of shear capacity. The study contributes to the refinement of analytical approaches and offers design-oriented insights for the development of reliable shear design methodologies for post-tensioned hollow circular segmental concrete structures employed in offshore applications.

Keywords: hollow circular structures; crack models; rotating crack model; fixed crack model; segmental structure; DIANA FEA;offshore structures.

Date submitted: 05.11.2025     Date accepted: 17.07.2025

References

1. Ngo, D., Scordelis, A. C. (1967). Finite element analysis of reinforced concrete beams. Journal Proceedings, 64(3), 152-163.
2. Engen, M., Hendriks, M. A. N., Øverli, J. A., Åldstedt, E. (2019). Non-linear finite element analyses applicable for the design of large reinforced concrete structures. European Journal of Environmental and Civil Engineering, 23(11), 1381-1403.
3. Lukić, D., Zlatanović, E. (2014). Definition of cracks for the ultimate degeneration process of revolving ellipsoids. Archives for Technical Sciences, 11(1), 59-64.
4. Artem, L., Aleksei, P., Dmitry, B. (2020). Crack resistance of reinforced concrete and reinforced rubber concrete beams. Archives for Technical Sciences, 22, 21-26.
5. Jirásek, M., Zimmermann, T. (1998). Analysis of rotating crack model. Journal of Engineering Mechanics, 124(8), 842-851.
6. Bhattacharjee, S. S., Léger, P. (1994). Application of nonlinear fracture mechanics models to predict cracking in concrete gravity dams. Journal of Structural Engineering, 120(4), 1255-1271.
7. Vecchio, F. J. (2000). Disturbed stress field model for reinforced concrete: formulation. Journal of Structural Engineering, 126(9), 1070-1077.
8. Hajiyev, M. A., Aeinehchi, S., Bashirzade, S. R., et al. (2024). Structural performance of compressive-zone strengthened RC elements. Scientific and Technical Journal on Engineering Mechanics, 8(2), 56–72.
9. Vecchio, F. J., Lai, D., Shim, W., Ng, J. (2001). Disturbed stress field model for reinforced concrete: validation. Journal of Structural Engineering, 127(4), 350-358.
10. Malm, R., Holmgren, J. (2008). Cracking in deep beams owing to shear loading. Part 1: Experimental study and assessment. Magazine of Concrete Research, 60(5), 371-379.
11. Malm, R. (2008). Predicting shear type crack initiation and growth in concrete with non-linear finite element method. Dissertation. Sweden, Stockhalm: Royal Institute of Technology (KTH).
12. Bashirzade, S. R., Hajiyev, M. A., Lipin, A. A., et al. (2025). Comprehensive study on nonlinear analysis of RC members under combined loads using advanced element and concrete models. International Journal on Technical and Physical Problems of Engineering, 17(1), 392–402.
13. Malm, R., James, G., Sundquist, H. (2006). Monitoring and evaluation of shear crack initiation and propagation in webs of concrete box-girder sections. In: Proceedings of the International Conference on Bridge Engineering - Challenges in the 21st Century, Hong Kong.
14. Mosler, J., Meschke, G. (2003). 3D modelling of strong discontinuities in elastoplastic solids: fixed and rotating localization formulations. International Journal for Numerical Methods in Engineering, 57(11), 1553-1576.
15. Rosales, M. B., Filipich, C. P., Buezas, F. S. (2009). Crack detection in beam-like structures. Engineering Structures, 31(10), 2257-2264.
16. Nematollahi, M. A., Farid, M., Hematiyan, M. R., Safavi, A. A. (2012). Crack detection in beam-like structures using a wavelet-based neural network. Proceedings of the Institution of Mechanical Engineers. Part G: Journal of Aerospace Engineering, 226(10), 1243-1254.
17. Chasalevris, A. C., Papadopoulos, C. A. (2006). Identification of multiple cracks in beams under bending. Mechanical Systems and Signal Processing, 20(7), 1631-1673.
18. Kupfer, H., Bulicek, H. (1991). Comparison of fixed and rotating crack models in shear design of slender concrete beams. In: Proceedings of an International Workshop on Progress and Advances in Structural Engineering and Mechanics. Dordrecht: Springer Netherlands.
19. Queiroz, F. O., Horowitz, B. (2016). Shear strength of hollow circular sections. Revista IBRACON de Estruturas e Materiais, 9(2), 214-225.
20. (2004). CSA A23.3-04: Design of concrete structures. Standard CAN/CSA A23.3-04. Mississauga, Ontario: Canadian Standards Association.
21. Bentz, E. C., Collins, M. P. (2006). Development of the 2004 Canadian Standards Association (CSA) A23.3 shear provisions for reinforced concrete. Canadian Journal of Civil Engineering, 33(5), 521-534.
22. (2014). NBR 6118: Projeto de estruturas de concreto: procedimento. Rio de Janeiro, RJ: Associação Brasileira de Normas Técnicas.
23. (1999). Guide specifications for design and construction of segmental concrete bridges. USA: American Association of State Highway and Transportation Officials.
24. Rombach, G. A. (2004). Dry joint behavior of hollow box girder segmental bridges. In: FIB Symposium. http://hdl. handle.net/11420/7271
25. Turmo, J., Ramos, G., Aparicio, J. A. (2006). Shear strength of match cast dry joints of precast concrete segmental bridges: proposal for Eurocode 2. Materiales de Construcción, 56(282), 45-52.
26. (1996). ATEP: Proyecto y construcción de puentes y estructuras con pretensado exterior. H.P.10-96. Madrid: Colegio de Ingenieros de Caminos, Canales y Puertos.
27. Bashirzade, S., Ozcan, O., Cagdas, I. U. (2024). Internal force transfer in segmental reinforced concrete structures. Research on Engineering Structures & Materials, 741, 1639-1662.
28. Bashirzade, S. (2024). Ard Germeli segmental açık deniz yapıların tasarımı. PhD Dissertation. Akdeniz University Graduate School of Natural and Applied Sciences.
29. Rots, J. G. (1988). Computational modeling of concrete fracture. Doctoral Thesis. Technische Universiteit Delft.
30. Giffin, B. D., Zywicz, E. (2023). A smeared crack modeling framework accommodating multi-directional fracture at finite strains. International Journal of Fracture, 239(1), 87-109. 
31. Mammadova, M. (2022). Investigation of fluid dynamics in microfracture channels. Eastern-European Journal of Enterprise Technologies, 4(7(118)), 42–50.
32. Mammadova, M. (2024). Development of a new method for solving problems of compressing various liquids with the manifestation of the «microcrack-liquid» effect. Eureka: Physics and Engineering, 2, 34-44.
33. Ferreira, D., Manie, J. (2022). DIANA finite element analysis: DIANA documentation - Release 10.4. The Netherlands: DIANA FEA.
34. (1993). CEB-FIP Model Code 1990. Bulletin d’information No. 213/214. Comité Euro-International du Béton.
35. Kaya, S., Salim, D. (2017). Shear stiffness and capacity of joints between precast wall elements. Master Thesis. Stockholm, Sweden: Royal Institute of Technology (KTH).
36. Turmo, J., Ramos, G., Aparicio, A. C. (2006). Study of the structural behaviour under flexure and shear of segmental concrete bridges with external prestressing and dry joints. Spain: ACHE.
37. Ramirez, G., MacGregor, R., Kreger, M. E., et al. (1993). Shear strength of segmental structures. In: Proceedings of the Workshop AFPC External Prestressing in Structures, Saint-Rémy-lès-Chevreuse.

One of the most pressing issues in the petrochemical and oil refining industries is carbon dioxide corrosion, which causes significant damage to equipment and leads to both economic and operational challenges globally. In this study, amides were synthesized through the reaction of natural petroleum acid with aniline and benzylamine. The chemical structure of the amides was characterized using Nuclear Magnetic Resonance spectroscopy (1H and 13C) and Infrared spectroscopy. Electrochemical and extrapolation of cathodic and anodic Tafel lines methods were used to evaluate the inhibitory effect of the aniline and benzylamine derivatives of natural petroleum acid on the corrosion rate in a 1% aqueous NaCl solution saturated with CO₂. The electrochemical measurements indicated that the inhibition efficiency increased with the concentration of the inhibitors, reaching a maximum of 91–93 % at a concentration of 100 ppm. One of the key aspects of this work was the study of the adsorption of the amides on the surface of carbon steel, which was carried out using the Langmuir adsorption isotherm. The obtained correlation constants allowed for the assessment of the degree of adsorption of the inhibitors on the metal surface and their interaction with it. The results demonstrate that the synthesized amides exhibit high inhibitory activity, leading to a significant reduction in the corrosion rate and improvement of the protective properties of steel. These findings support the potential application of the amides as effective corrosion inhibitors in the petrochemical and oil refining industries, which could significantly increase equipment longevity and reduce maintenance and replacement costs. 

Keywords: corrosion; inhibitor; adsorption; amides; inhibition efficiency.

Date submitted: 12.02.2025     Date accepted: 07.07.2025

References

1. Kaczerewska, O., Leiva-Garcia, R., Akid, R., Brycki, B. (2017). Efficiency of cationic gemini surfactants with 3-azamethylpentamethylene spacer as corrosion inhibitors for stainless steel in hydrochloric acid. Journal of Molecular Liquids, 247, 6–13.
2. Goyal, M., Kumar, S., Bahadur, I., et al. (2018). Organic corrosion inhibitors for industrial cleaning of ferrous and non-ferrous metals in acidic solutions: a review. Journal of Molecular Liquids, 256, 565–573.
3. Kadhim, M. G., Ali, M. T. (2017). A critical review on corrosion and its prevention in the oilfield equipment. Journal of Petroleum Research and Studies, 7(2), 162-189.
4. Iannuzzi, M., Barnoush, A., Johnsen, R. (2017). Materials and corrosion trends in offshore and subsea oil and gas production. npj Materials Degradation, 1, 2.
5. Afzali, P., Yousefpour, M., Borhani, E. (2018). Effect of deformation-induced defects on the microstructure and pitting corrosion behavior of Al-Ag alloy. International Journal of Engineering Transactions C: Aspects, 31(12), 2092-2101.
6. Askari, M., Aliofkhazraei, M., Jafari, R., et al. (2021). Downhole corrosion inhibitors for oil and gas production – a review. Applied Surface Science Advances, 6, 100128. 
7. Punitha, N., Sundaram, R. G., Vengatesh, G., et al. (2023). Bis-1,2,3-triazole derivative as an efficient corrosion inhibitor for mild steel in hydrochloric acid environment: Insights from experimental and computational analysis. Inorganic Chemistry Communications, 153, 110732.
8. Tan, B., Ren, H., Zhng, R., et al. (2025). A novel corrosion inhibitor for copper in sulfuric acid media: Complexation of iodide ions with Benincasa hispida leaf extract. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 705, 135710.
9. He, Z., Xiong, L., Zhang, R., et al. (2019). The synergistic inhibition effects of oleic imidazoline quaternary ammonium salt and sulfonate on Q235 steel corrosion in HCl media. Surface Topography: Metrology and Properties, 7(4), 045005.
10. Brycki, B., Szulc, A. (2021). Gemini surfactants as corrosion inhibitors: A review. Journal of Molecular Liquids, 344, 117686.
11. El Defrawy, A. M., Abdallah, M., Al-Fahemi, J. H. (2019). Electrochemical and theoretical investigation for some pyrazolone derivatives as inhibitors for the corrosion of C-steel in 0.5 M hydrochloric acid. Journal of Molecular Liquids, 288, 110994.
12. Jafari, Y., Ghoreishi, S., Shabani-Nooshabadi, M. (2017). Electrosynthesis, characterization and corrosion inhibition study of DBSA-doped polyaniline coating on 310 stainless steel. Iranian Journal of Chemistry and Chemical Engineering, 36(5), 23-32.
13. Touir, R., Errahmany, N., Rbaa, M., et al. (2024). Experimental and computational chemistry investigation of the molecular structures of new synthetic quinazolinone derivatives as acid corrosion inhibitors for mild steel. Journal of Molecular Structure, 1303, 137499.
14. Tariq, Z., Hassan, A., Al-Abdrabalnabi, R., et al. (2021). Comparative study of fracture conductivity in various carbonate rocks treated with GLDA chelating agent and HCl acid. Energy & Fuels, 35, 19641–19654.
15. Yue, Q.-X., Wu, L.-F., Lv, J., et al. (2021). Study on anti-corrosion performance and mechanism of epoxy coatings based on basalt flake loaded aniline trimer. Colloid and Interface Communications, 45, 100505.
16. Afandiyeva, L., Abbasov, V., Aliyeva, L., et al. (2018). Investigation of organic complexes of imidazolines based on synthetic oxy- and petroleum acids as corrosion inhibitors. Iranian Journal of Chemistry and Chemical Engineering, 37(3), 73-79.
17. Hu, S., Cui, P., Wang, C., et al. (2019). Rapid synthesis and evaluation of a cheaper corrosion inhibitor for steel in HCl solution. Iranian Journal of Chemistry and Chemical Engineering, 38(3), 117-125.
18. Dadashova, N. K. (2020). Synthesis of amides of aniline and benzylamine of natural petroleum acids and their use as the components of preserving fluids. Processes of Petrochemistry and Oil Refining, 2(1), 146–154.
19. Abbasov, V. M., Mammadov, E. A., Dadashova, N. K., et al. (2024). The inhibition efficiency of nitrated cottonseed oil on corrosion of mild carbon steel in CO₂ medium. Processes of Petrochemistry and Oil Refining, 25(3).
20. Abbasov, V. M., Aghamaliyeva, D. B., Afandiyeva, L. M., et al. (2024). The study of the effect of alkylhalogenide complexes of amidoamine of corn oil on the kinetics of CO₂ corrosion. Processes of Petrochemistry and Oil Refining, 25(2), 313-322.
21. Abbasov, V. M., Aghamaliyeva, D. B., Mursalov, N. I., et al. (2015). Investigation of imidazoline derivatives obtained from synthetic petroleum acids as corrosion inhibitors. Journal of Advances in Chemistry, 11(1), 3372-3381.
22. Abbasov, V. M., Məmmədbəyli, E. H., Ağamalıyeva, D. B., et al. (2017). Effect of inorganic complexes of imidazoline based on synthetic petroleum acids and triethylenetetramine against carbon dioxide corrosion. Kimya Problemleri, 4, 364-369.
23. Aghamaliyev, Z. Z. (2021). Production and properties of surface-active compositions based on oxyetized nonylphenol and alkylimidazolines. Processes of Petrochemistry and Oil Refining, 22(1), 50-57.
24. Abbasov, V. M., Mammadov, E. A., Dadashova, N. K., et al. (2022). Synthesis of some nitrogen derivatives of natural
    petroleum acids and their application as a component of conservative liquids. Processes of Petrochemistry and Oil Refining, 23(2), 184–189.
25. Ogunyemi, B. T., Latona, D. F., Ayinde, A. A., Adejoro, I. A. (2020). Theoretical investigation to corrosion inhibitor efficiency of some chloroquine derivatives using density functional theory. Advanced Journal of Chemistry. Section A, 3, 485-492.
26. Belghiti, M. E., Bouazama, S., Echihi, S., et al. (2020). Understanding the adsorption of newly benzylideneaniline
    derivatives as a corrosion inhibitor for carbon steel in hydrochloric acid solution: experimental, DFT and molecular dynamic simulation studies. Arabian Journal of Chemistry, 13(1), 1499–1519.
27. Avci, G. (2008). Corrosion inhibition of indole-3-acetic acid on mild steel in 0.5 M HCl. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 317(1-3), 730-736.
28. Solmaz, R., Kardas, G., Culha, M., et al. (2008). Investigation of adsorption and inhibitive effect of 2-mercaptothiazoline on corrosion of mild steel in hydrochloric acid media. Electrochimica Acta, 53(20), 5941–5952.
29. Issaadi, S., Douadi, T., Zouaoui, A., Chafaa, S., Khan, M. A., & Bouet, G. (2011). Novel thiophene symmetrical schiff base compounds as corrosion inhibitor for mild steel in acidic media. Corrosion Science, 53(4), 1484–1492.
30. Refay, S. A., Taha, F., Abd El-Malak, A. M. (2004). Inhibition of stainless steel pitting corrosion in acidic medium by 2-mercaptobenzoxazole. Applied Surface Science, 236(1–4), 175–185.

This article considers the issue of creating a new economic and mathematical model for assessment of synergistic effects arising from the effective management of enterprises in the oil and gas industry. Using the Eviews-12 software package, based on the correlation and regression analysis method, the dependencies between the total profit obtained from the synergistic effect arising from the effective management of enterprises in innovative economic conditions in 2007-2023, the volume of innovative products from the level of innovation of the industry, investments in fixed assets of the industry and the costs of technological innovations at industrial enterprises are estimated. It is determined that the level of innovations in the oil and gas industry and the increase in the volume of innovative products from the costs of technological innovations at industrial enterprises have a direct positive impact on the increase in total profit as a result of the synergistic effect arising from the effective management of enterprises. Innovations ensure sustainable development of enterprises and enhance economic development through effective management. Using this economic and mathematical model, the forecast values of the total profit arising from the synergistic effect manifested in the effective management of enterprises in the oil and gas industry based on the innovative development of the economy in Azerbaijan until 2030 were determined. Based on calculation of economic consequences of changes, it was determined that the synergistic effects arising from the combination of innovations and effective management, which are of strategic importance for the enterprise, have a significant impact on the management process. 

Keywords: sinergetics; sinergistic effect; investments; innovation; management; correlation; regression; elasticity coefficient; economic-mathematical model.

Date submitted: 02.06.2025     Date accepted: 01.09.2025

References

1. Aziz, K. (2017). Eviews is a very balanced time series that should be heard. Turkey, Kochaeli University: Uuttepe Publications.
2. Berkovitch, E. Narayan, M. (2003). Motives for takeovers: An empirical investigation. Journal of Financial and Quantitative Analysis, 3(28), 347-362.
3. Damodaran, A. (2005). The value of synergy. USA, New York: Stern School of Business.
4. Bradley, M., Desai, А., Kim, Е. (2013). The rationale behind interfirm tender offers: information or synergy ? Journal of Financial Economics, 2(11), 183-206.
5. Dougherty, C. (2011). Introduction to econometrics. 2nd Ed. USA: Oxford University Press.
6. Gujarati, D. N., Porter, D. E. (2009). Essentials of econometrics. 2nd Ed. USA: McGraw-Hill/ Irwin.
7. Abdokova, L. Z. (2016). Synergistic effect - as a result of effective management. Fundamental Research, 10, 581-584.
8. Kelbiyev, Y. A., Safarova, G. N. (2025). The creation of synergistic effects in the management process of enterprises and the possibility of the irtargeteduse. Polish Journal of Science, 87, 15-20.
9. Lyakhov, A. V., Golovina, A. K. (2009). Directions for creating a synergistic effect and methods of managing synergy. Industrial Economics, 48(5), 19–27.
10. Kasyanenko, T. G., Ivanov, D. A. (2017). Synergy in the modern economy: definition and typology. Economics and Management: Problems, Solutions, 4(6), 18–25.
11. Ivanov, A. E. (2022). Synergistic effect of company integration: formation mechanism, assessment, accounting. Moscow: Rior.
12. Fleck, M. B., Boguslavsky, I. V., Ugnich, E. A. (2014). Management of synergistic effects - the main driver of enterprise development in modern conditions. Bulletin of the Don State Technical University, 14(4), 21-30.
13. Aimbetov, N. K., Niyazimbetov, M. K. (2023). Synergic economy as a methodology for modeling complex economic processes. Oriental Journal of Economics, Finance and Management, 3, 11-17.
14. Avdonina, S. G. (2012). Quantitative methods for assessing the synergistic effect of an innovative cluster. Management of Economic Systems, 3, 13-19.
15. Arshinov, V. I. (2011). Synergetic paradigm: Synergetics of innovative complexity. Moscow, Progress-Tradition.
16. Knyazeva, E. N., Kurdyumov, S. P. (2014). Synergetics: nonlinearity of time and landscapes of coevolution. Moscow: Kom-Kniga.
17. Safarova, G. N. (2024). Ways to increase the efficiency of enterprise management processes in conditions of uncertainty. Universum, 11(121), 24-27.
18. Ayurov, V. D. (2005). Synergetics of the economy. Moscow State University for the Humanities.
19. Vishnyakov, V. V., Suleimanov, B. A., Salmanov, A. V., Zeynalov, E. B. (2019). Primer on enhanced oil recovery. Gulf Professional Publishing.
20. Berezhnaya, E. V., Berezhnoy, V. I. (2006). Mathematical methods of modeling economic systems. 2nd Ed. Moscow: Finance and Statistics.
21. Vakulyuk, V. S. (2006). Synergy in the economy. Problems of Economics and Management, 1(12), 28–30.
22. Yadigarov, T. A. (2020). Operations research and econometric problem solving in MS Excel and Eviews software packages: Theory and Practice. Baku: Europe Publishing House.
23. Suleimanov, B. A., Veliyev, E. F., Vishnyakov, V. V. (2022). Nanocolloids for petroleum engineering: Fundamentals and practices. John Wiley & Sons.
24. Abdullayev, V. J., Alieva, N. T., Gamzaeva, N. Kh., Gamzaev, Kh. M. (2022). About one model of infiltration of oil and petroleum products into the ground during their spills. SOCAR Proseedings, 4, 72-77.
25. Abdullayev, V. J., Huseynov, M. A., Ismayilov, M. M., Nabiyev, K. M. (2014). 3D geological modeling of «Guneshli» reservoir for increating final development stage efficiency. SOCAR Proceedings, 2, 75-82.
26. Ivanov, D. A., Kasyanenko, T. G. (2019). Formation and assessment of the synergistic effect of the synergy of the association. Intellectual Property, 5, 34-39.
27. Safarova, G. N. (2023). On the possibilities of applying synergy in economic processes. Azerbaijan Oil Industry, 10, 53-55.
28. Galeeva, E. I. (2008). Evaluation of the efficiency of economic entities using a synergetic model. Bulletin of the Chuvash University, 3, 311–319.
29. Yadigarov, T. A. (2020). Customs statistics and modern information technologies. Baku: Europe Publishing House.
30. Suleimanov, B. A., Rzayeva, S. J., Akberova, A. F., Akhmedova, U. T. (2022). Self-foamed biosystem for deep reservoir conformance control. Petroleum Science and Technology, 40(20), 2450-2467.
31. Suleimanov, B. A., Rzayeva, S. J., Akhmedova, U. T. (2021). Self-gasified biosystems for enhanced oil recovery. International Journal of Modern Physics B, 35(27), 215-274.
32. Zhurova, L. I. (2016). Approaches to assessing the synergistic effect of a corporate system. Volzhsky University named after V.N. Tatishchev, 3, 26–31.
33. Gasimov, A. A., Hajiyev, G. B. (2021). On management evaluation of oil-gas industry enteprises in modern economic condition. SOCAR Proceedings, 3, 100-106.
34. Gasumov, E. R., Gasumov, R. A. (2020). Innovative risk management for geological and technological measures at oil and gas fields. SOCAR Proceedings, 2, 8-16.
35. Grunina, O. A. (2011). The essence of the synergetic effect in the economy. Bulletin of the North Caucasian State Technical University, 4(17), 36-40. 
36. Korechkov, Yu. V., Dzhioev, O. V. (2015). Synergetic effect of integration processes and investment multiplication in integrated organizations. Naukovedenie, 2, 101-109.
37. Mammadov, M. A., Yadigarov, T. A., Mammadova, F. A., et al. (2024). An economic and mathematical modeling for risk assessment of innovative activities an enterprise in oil and gas industry. SOCAR Proceedings, 4, 139-146.
38. Suleymanov, Q. S., Salimova, S. G., Kuliyev, J. K. (2020). A methodic approach to the solution of problem of main stock usage effictiveness. SOCAR Proceedings, 3, 142-147.
39. Mirgeydarova, A. I., Mammadova, E. G. (2025). Mechanism of strategic management of innovative activity in industry. SOCAR Proceedings, 2, 153-158.
40. Ross, G. V., Gataullin, T. M., Pleshakova, E. S., et.al. (2025). Application of the mathematical apparatus of synergy to the description of economic models of behavior. Theoretical and Applied Economics, 3, 25-46.
41. http: www.stat.gov.az
42. Yadigarov, T. A. (2022). Econometric assessment of the level of development of balanced foreign economic relations in conditions of uncertainty. Finance: Theory and Practice, 26(1), 79–90.
43. Musayev, L. A. (2011). Evaluation of the synergistic effect of economic systems. Bulletin of SRSTU, 3, 132–136.
44. Myasnikov, A. A. (2023). Synergistic effects in the modern economy: Introduction to the problematic. 2nd Ed. Moscow: URSS.
45. Milovanov, V. P. (2020). Synergetics and self-organization: Methods of mathematical modeling in economics. Moscow: Librokom.
46. Sukharev, O. S., Shmanev, S. V., Kuryanov, A. M. (2008). Synergetics of investments. Moscow: Finance and Statistics.
47. Rovinsky, R. E. (2006). Synergetics and processes of development of complex systems. Questions of Philosophy, 2, 162–169.
48. Alekseevsky, V. S. (2017). Synergetics of management (management of sustainable development of dissipative systems). Moscow: Librokom.
49. Hasanov, Kh. I., Shakhbazov, E. G., Khalilov, N. N. (2022). Inhibitor for nitrogen-containing hardness deposition based on ethanolammonium phosphates. Socar Proseedings, 2, 67-72
50. Ismayilov, F. S., Ismayilov, G. G., Safarov, N. M. (2022). On the possibility of regulation of rheophysical properties multicomponent mixtures based on rheotechnology. Socar Proseedings, 1, 77-83.

With 2% of the world's oil reserves, the Republic of Kazakhstan is among the fifteen leading countries in the world. Oil fields in Kazakhstan are located on more than 60% of the territory of the republic, and the number of oil fields is 172, proven reserves in category «C» are 6.3 billion tons, and natural gas is about 2 trillion m3. The Republic of Kazakhstan has gained independence and is strengthening its economy, integrating into the world. All this requires improving the use of human resources. In the context of globalization, one of the main strategies of modern business is effective human resource management. A huge number of scientific works by economists from near and far abroad countries are devoted to human resource management issues. Understanding the strategic importance of decisions related to rational human resource management, global companies actively use the services of specialized infrastructures that provide consulting services in the field of human resource management. International competition requires a new worldview, a new approach to business, and the development of new ways of thinking. In the global economy, there is a constant exchange of ideas, and the rapid movement of goods and people. Companies need mobile employees who can work in unfamiliar conditions and adapt to other cultures, since success in the oil and gas business today is determined by the ability to operate in conditions of political and economic instability. A global approach to doing business requires a high educational and professional level of all employees of the corporation. The article examines a dynamic model for determining the number of employees by management functions in oil and gas producing enterprises.

Keywords: oil and gas production; number; dynamic model; regression; enterprise; theory; investments; effect; investments.

Date submitted: 20.05.2025     Date accepted: 25.08.2025

References

1. Jnitova, V., Joiner, K., Efatmaneshnik, M., Chang, E. (2021). Modelling workforce employability pipelines for organisational resilience: combining business process and system dynamics modelling. Journal of Human Resource Modelling, 10(4), 19–40.
2. Obiri, K. A., Omotayo, T. S., Bjeirmi, B., Boateng, P. (2021). Long-term dynamic behaviour of human resource needs in Ghana’s oil sector: System dynamics approach. Sustainability, 13(6), 3546.
3. Cave, S., Willis, G. (2019). System dynamics and workforce planning. In: Meyers, R. (Eds). Encyclopedia of complexity and systems science. Berlin, Heidelberg: Springer.
4. Zurn, P., Poz, M. R. D., Stilwell, B., Adams, O. (2004). Imbalance in the health workforce. Human Resources for Health, 2(1), 13.
5. Ablo, A. D. (2018). Scale, local content and the challenges of Ghanaians employment in the oil and gas industry. Geoforum, 96, 181–189.
6. Habsi, A. H. A., Farhana, N., Karim, A. M. (2021). Impact of HR practices on employee retention in oil and gas industries of Oman. International Journal of Academic Research in Business and Social Sciences, 11(9), 1520–1530.
7. Ajayi, S. (2020). Effects of globalization on human resources practice in Nigeria oil & gas industry. SSRN Electronic Journal. https://doi.org/10.2139/ssrn.3532759
8. Boateng, P., Chen, Z., Ogunlana, S. O. (2016). A dynamic framework for managing the complexities of risks in megaprojects. International Journal of Technology and Management Research, 1(5), 1-13.
9. Lepak, D. P., Snell, S. A. (1998). Virtual HR: Strategic human resource management in the 21st century. Human Resource Management Review, 8(3), 214 234.
10. Crowder, R. M., Robinson, M. A., Hughes, H. P. N., Sim, Y. W. (2012). The development of an agent-based modeling framework for simulating engineering team work. In: IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans, 42(6), 1425-1439.
11. Zhang, H., Li, Y. (2024). Dynamic simulation of staffing levels in the upstream oil sector using system dynamics. Energy Workforce Studies, 9(3), 150–169.
12. Chen, L., Wang, F. (2023). Dynamic programming approach toward optimization of workforce planning decisions. Journal of Construction Engineering and Management, 144(2).
13. Fadeev, A., Komendantova, N., Cherepovitsyn, A., et al. (2021). Methods and priorities for human resource planning in oil and gas projects in Russia and OPEC. OPEC Energy Review. https://pure.iiasa.ac.at/17360
14. Mahdavi, S. F., Sohrabi, B., Farajzadeh, M. (2021). Designing and compiling a human capital management model in West Oil and Gas Exploitation Company. Strategic Studies in Petroleum and Energy Industry, 12(48), 238–251.
15. Salleh, R., Lohana, S., Kumar, V., Nooriza, S. (2024). Evaluation of job satisfaction as a mediator: Exploring the relationship between workload, career growth, social support supervisory and talent retention in the oil and gas industry in Malaysia. The Extractive Industries and Society, 17, 101426.
16. Barro, R. J. (1991). Economic growth in a cross section of countries. Quarterly Journal of Economics, 106(2), 407-443.
17. Galar,O., Zeira, J. (1993). Income distribution and macroeconomics. Review of Economic Studies, 60, 35-42.
18. Romer, P. M. (1990). Endogenous technological change. Journal of Political Economy, 98(5), 71- 102. 
19. Bernardin, H. J. (2013). Human resource management: an experiential approach. New York: McGraw-Hill/Irwin.
20. Harvey, D. F., Bowin, R. B. (2001). Human Resource Management: An experiential approach. Upper saddle Rive, New Jersey: Prentice Hall.
21. Safarov, Q., Sadıqova, S., Urazayeva, M. (2023). Metological approach to identification of innovative determinants of human capital management. Marketing and Management of Innovations, 2, 255-267.
22. Basovsky, L. E. (2003). Forecasting and planning in market conditions. Moscow: Infra-M.
23. Kibanov, A. Y. (2006). Personnel management in an organization. Moscow: Infa-M.
24. Spivak, V. A. (2007). Personnel management for managers. Moscow: Eksmo.
25. Porter, M. (2005). Competitive advantage. Moscow: Alpina Business.
26. Bento, F. (2018). Complexity in the oil and gas industry the problem of emergency: a study into exploration and exploitation in integrated operations. Journal of Open Innovation Technology Market and Complexity, 4(1), 1–17.
27. Frynas, J. G. (2009). Corporate social responsibility in the oil and gas sector. The Journal of World Energy Law & Business, 2(3), 178–195.
28. Middleton, R. S., Gupta, R., Hyman, J. D., Viswanathan, H. S. (2017). The shale gas revolution: Barriers, sustainability, and emerging opportunities. Applied Energy, 199, 88–95.
29. Wiig, A., Kolstad, I. (2012). If diversification is good, why don’t countries diversify more? The political economy of diversification in resource-rich countries. Energy Policy, 40, 196–203.
30. Morecroft, J. D. (2017). Enduring feedback structure and long-term futures for the upstream oil industry. Systems Research and Behavioral Science, 34(4), 494–509.
31. Leighty, W., Lin, C. Y. C. (2012). Tax policy can change the production path: A model of optimal oil extraction in Alaska. Energy Policy, 41, 759–774.
32. Auty, R. M. (2007). Natural resources, capital accumulation and the resource curse. Ecological Economics, 61(4), 627–634.
33. Teece, D. J. (2007). Explicating dynamic capabilities: the nature and micro foundations of (sustainable) enterprise performance. Strategic Management Journal, 28, 1319-1350.
34. Vishnyakov, V. V., Suleimanov, B. A., Salmanov, A. V., Zeynalov, E. B. (2019) Primer on enhanced oil recovery. Gulf Professional Publishing.
35. Suleimanov, B. A., Veliyev, E. F., Vishnyakov, V. V. (2022). Nanocolloids for petroleum engineering: Fundamentals and practices. John Wiley & Sons.
36. Suleimanov, B. A., Rzayeva, S. J., Akberova, A. F., Akhmedova, U. T. (2022). Self-foamed biosystem for deep reservoir conformance control. Petroleum Science and Technology, 40(20), 2450-2467.
37. Suleimanov, B. A., Rzayeva, S. J., Akhmedova, U. T. (2021). Self-gasified biosystems for enhanced oil recovery. International Journal of Modern Physics B, 35(27), 2150274.
38. Gasimov, A. A., Hajiyev, G. B. (2021). On management evaluation of oil-gas industry enterprises in modern economic condition. SOCAR Proceedings, 3, 100-105.
39. Kolesnyk, S. V., Shangin, E. S. (2021). Economic method of oil production based on electrophoresis. SOCAR Proceedings, 2, 97-102.
40. Leybert, T. B., Khalikova, E. A. (2020). Economic evaluation of the effectiveness of design solution for the installation of a compressor station for the preparation and transportation of associated petroleum-gas. SOCAR Proceedings, 1, 70-78.
41. Burenina, I. V., Gerasimova, M. V., Khalilova, M. A., et al. (2020). Concept for managing constraints of an oil field developments projects. SOCAR Proceedings, 4, 95-102.
42. Mehdiyev, F. R. (2019). Methods for determination of oil loss in refining mechanical impurities centrifuges. SOCAR Proceedings, 4, 81-84.
43. Shammazov, A. M., Shammazov, I. A., Boykov, I. R., et al. (2018). Optimization of the oil and gas companies energy strategy. SOCAR Proceedings, 4, 65-69.
44. Yadigarov, T. A. (2019). Operations research and solution of econometric issues in MS Excel and E-views software packages: theory and practice (monograph). Baku.
45. Yadigarov, T. A. (2022). Econometric assessment of the level of development of balanced foreign economic relations in conditions of uncertainty. Finance: Theory and Practice, 26(1), 79–90.

In the paper we study the fractional maximal operator M_Γ,α defined on Carleson curves Γ in the generalized local weighted Morrey space and the generalized weighted Morrey space M_p,φ (Γ, ω), respectively. We give a strong and weak type Guliyev-Spanne type boundedness criterion for the fractional maximal operator M_Γ,α in the generalized local weighted Morrey space  and the generalized weighted Morrey space M_p,φ (Γ, ω) defined on Carleson curves Γ. For the operator MΓ,α, necessary and sufficient conditions for strong and weak boundedness of the Guliyev-Spanne type on  and the strong and weak Guliyev-Spanne type boundedness on M_p,φ (Γ, ω) are established. We shall give characterizations the strong and weak Guliyev-Spanne type boundedness of the operator M_Γ,α from  to  and from the space  to the weak space . We can apply this boundedness of fractional maximal operators in the local generalized weighted Morrey space  and the generalized weighted Morrey space M_p,φ (Γ, ω) defined on Carleson curves Γ to study the regularity in local generalized weighted Morrey of of the Navier-Stokes equations. Solutions of the Navier-Stokes equations often include turbulence, which remains one of the greatest unsolved problems in physics, despite its immense importance in science and engineering. The possibilities nowadays to exploit supercomputers and highly developed numerical methods for nonlinear partial differential equations allow us to determine even the general solutions to the Navier-Stokes equations. However the difficulties become greater with increasing Reynolds number. This has to do with the particular structure of the solutions at high Reynolds numbers. Note that in the limiting case of high Reynolds numbers, most of these exact solutions have a boundary-layer character. 

Keywords: Carleson curve; generalized local weighted Morrey space; fractional maximal operator; Guliyev-Spanne type boundedness.

Date submitted: 31.07.2025 Date accepted: 31.08.2025

References

1. Morrey, C. B. (1938). On the solutions of quasi-linear elliptic partial differential equations. Transactions of the American Mathematical Society, 43, 126-166.
2. Akbulut, A., Omarova, M. N., Serbetci, A. (2025). Generalized local mixed Morrey estimates for linear elliptic systems with discontinuous coefficients. SOCAR Proccedings, 1, 136-142.
3. Di Fazio, G., Ragusa, M. A. (1993). Interior estimates in Morrey spaces for strong solutions to nondivergence form equations with discontinuous coefficients. Journal of Functional Analysis, 112, 241-256.
4. Guliyev, V. S., Serbetci, A. (2024). Generalized local Morrey regularity of elliptic systems. SOCAR Proceedings, 2, 131-136.
5. Guliyev, V. S., Serbetci, A., Ekincioglu, I. (2024). Weighted Sobolev-Morrey regularity of solutions to variational inequalities. Azerbaijan Journal of Mathematics, 14(1), 94-108.
6. Omarova, M.N. (2024). Global regularity in parabolic weighted Orlicz-Morrey spaces of solutions to parabolic equations with BMO coefficients. Journal of Mathematical Inequalities, 18(3), 865-896.
7. Guliyev, V. S. (1994). Integral operators on function spaces on the homogeneous groups and on domains in Rn. Doctoral dissertation. Moscow: Steklov Mathematical Institute.
8. Mizuhara, T. (1991). Boundedness of some classical operators on generalized Morrey spaces /In: Harmonic analysis (S. Igari, Ed.), ICM 90 Satellite Proceedings. Springer - Verlag, Tokyo.
9. Nakai, E. (1994). Hardy-Littlewood maximal operator, singular integral operators and Riesz potentials on generalized Morrey spaces. Mathematische Nachrichten, 166, 95-103.
10. Guliyev, V. S. (1999). Function spaces, integral operators and two weighted inequalities on homogeneous groups. Some applications. Baku.
11. Guliyev, V. S. (2009). Boundedness of the maximal, potential and singular operators in the generalized Morrey spaces. Journal of Inequalities and Applications, ID 503948.
12. Guliyev, V. S. (2013). Local generalized Morrey spaces and singular integrals with rough kernel. Azerbaijan Journal of Mathematics, 3(2), 79-94.
13. Sawano, Y. (2019). A thought on generalized Morrey spaces. Journal of the Indonesian Mathematical Society, 25(3), 210-281.
14. Komori, Y., Shirai, S. (2009). Weighted Morrey spaces and a singular integral operator. Mathematische Nachrichten, 282(2), 219-231.
15. Guliyev, V. S. (2012). Generalized weighted Morrey spaces and higher order commutators of sublinear operators. Eurasian Mathematical Journal, 3(3), 33-61.
16. Armutcu, H., Eroglu, A., Isayev, F.A. (2020). Characterizations for the fractional maximal operators on Carleson curves in local generalized Morrey spaces. Tbilisi Mathematical Journal, 13(1), 23-38.
17. Böttcher, A., Karlovich, Yu. I. (1997). Carleson curves, Muckenhoupt weights, and Toeplitz operators. Basel, Boston, Berlin: Birkhauser Verlag.
18. Böttcher, A., Karlovich, Yu. I. (1999). Toeplitz operators with PC symbols on general Carleson Jordan curves with arbitrary Muckenhoupt weights. Transactions of the American Mathematical Society, 351, 3143-3196.
19. Celik, S., Akbulut A., Omarova, M. N. (2025). Characterizations of anisotropic Lipschitz functions via the commutators of anisotropic maximal function in total anisotropic Morrey spaces. Transactions Issue Mathematics. National Academy of Sciences of Azerbaijan. Series of Physical-Technical & Mathematical Sciences, 45(1), 25-37.
20. Eroglu, A., Dadashova, I.B. (2018). Potential operators on Carleson curves in Morrey spaces. Communications Faculty of Sciences University of Ankara Series A1: Mathematics and Statistics, 66(2), 188-194.
21. Dadashova, I.B., Aykol, C., Cakir, Z., Serbetci, A. (2018). Potential operators in modified Morrey spaces defined on Carleson curves. Transactions of A.Razmadze Mathematical Institute, 172(1), 15-29.
22. Guliyev, V. S. (2024). Maximal commutator and commutator of maximal operator on Lorentz spaces. Transactions Issue Mathematics. National Academy of Sciences of Azerbaijan. Series of Physical-Technical & Mathematical Sciences, 44(4), 43-49.
23. Karlovich, A. Yu. (2010). Maximal operators on variable Lebesgue spaces with weights related to oscillations of Carleson curves. Mathematische Nachrichten, 283(1), 85-93.
24. Kokilashvili, V. (1989). Fractional integrals on curves. Doklady Akademii Nauk SSSR, 305(1), 33-35.
25. Kokilashvili, V., Samko, S. (2008). Boundedness of maximal operators and potential operators on Carleson curves in Lebesgue spaces with variable exponent. Acta Mathematica Sinica, English Series, 24(11), 1775-1800.
26. Guliyev, V. S. (2013). Generalized Holder estimates via generalized Morrey norms for Kolmogorov operators. Azerbaijan Journal of Mathematics, 15(1), 228-241.
27. Muckenhoupt, B. (1972). Weighted norm inequalities for the Hardy maximal function. Transactions of the American Mathematical Society, 165, 207-226.
28. Muckenhoupt, B., Wheeden, R. (1974). Weighted norm inequalities for fractional integrals. Transactions of the American Mathematical Society, 192, 261-274.
29. Guliyev, V. S., Hasanov, J. J., Zeren, Y. (2011). Necessary and sufficient conditions for the boundedness of the Riesz potential in modified Morrey spaces. Journal of Mathematical Inequalities, 5(4), 491-506.
30. Samko, N. (2009). Weighted Hardy and singular operators in Morrey spaces. Journal of Mathematical Analysis and Applications, 350(1), 56-72.
31. Kokilashvili, V., Meskhi, A. (2008). Boundedness of maximal and singular operators in Morrey spaces with variable exponent. Armenian Journal of Mathematics (Electronic), 1(1), 18-28. 
32. Burenkov, V., Gogatishvili, A., Guliyev, V. S., Mustafayev, R. (2010). Boundedness of the fractional maximal operator in local Morrey-type spaces. Complex Variables and Elliptic Equations, 55(8-10), 739-758.
33. Guliyev, V. S. (2013). Generalized local Morrey spaces and fractional integral operators with rough kernel. Journal of Mathematical Sciences (New York), 193(2), 211-227.
34. Guliyev, V. S., Omarova, M. N., Ragusa, M. A., Scapellato, A. (2018). Commutators and generalized local Morrey spaces. Journal of Mathematical Analysis and Applications, 457(2), 1388-1402.
35. Eroglu, A., Guliyev, V.S., Azizov, C.V. (2017). Characterizations for the fractional integral operators in generalized Morrey spaces on Carnot groups. Mathematical Notes, 102(5), 127-139.
36. Akbulut, A., Guliyev, V. S., Mustafayev, R. (2012), On the boundedness of the maximal operator and singular integral operators in generalized Morrey spaces. Mathematica Bohemica, 137(1), 27-43.
37. Celik, S. (2025). Maximal operator on Carleson curves in local generalized weighted Morrey spaces. Turkish Journal of Mathematics and Computer Science, 17(2), 1-7.
38. Bernardis, A., Hartzstein, S., Pradolini, G. (2006). Weighted inequalities for commutators of fractional integrals on spaces of homogeneous type. Journal of Mathematical Analysis and Applications, 322, 825-846.
39. Akbulut, A., Gadjiev, T. S., Serbetci, A., Rustamov, Y. I. (2023). Regularity of solutions to nonlinear elliptic equations in generalized Morrey spaces. Transactions Issue Mathematics. National Academy of Sciences of Azerbaijan. Series of Physical-Technical & Mathematical Sciences, 43 (4), 14-31.

This study comprehensively explores the wear mechanisms, restoration techniques, and precision mechanical processing methods applied to diesel engine injector needles, which play a critical role in ensuring accurate fuel atomization and efficient combustion in internal combustion engines. Subjected to extreme operational environments, these injector needles are prone to multiple forms of degradation, including abrasive, corrosive, thermal, mechanical, cavitation, and fatigue-related wear. The deterioration of the injector needle and the sprayer body directly affects fuel delivery efficiency and engine performance, often leading to increased emissions and fuel consumption. To address these challenges, the study proposes a restoration methodology that integrates vapor-phase diffusion chromotitanization – a thermochemical surface treatment that enhances hardness and wear resistance – with high-precision mechanical reprocessing. Specifically, the restored injector needles undergo grinding using synthetic diamond wheels of the AC6-100/80 MB1 type at 100% diamond concentration. Experimental optimization determined the ideal transverse feed to be 0.42 mm/min with a driving wheel speed of 50 min⁻¹. Following grinding, a multilayer finishing process is carried out using cast iron lapping tools and KT-based abrasive pastes to refine the surface texture. The resulting surface roughness values achieved were within Ra = 0.032–0.040 μm, and geometric deviations remained under 1 μm, matching or surpassing factory-level precision standards. The findings confirm that the proposed restoration process not only extends the operational life of injector needles but also supports sustainable engineering by reducing the need for complete part replacement. This contributes significantly to resource conservation and environmentally responsible maintenance practices in diesel engine technology.

Keywords: needle; spray body; nozzle; chrome-titanium plating.

Date submitted: 16.05.2025     Date accepted: 11.07.2025

References

1. Mehdiyev, T. R., Hashimov, A. M., Jabarov, S. H., et al. (2023). Cluster aggregation of Ni1-xZnxFe2O4 ferrospinels. Journal of Magnetism and Magnetic Materials, 587, 171326.
2. Aliyeva, Sh. N., Mehdiyev, T. R., Jabarov, S. H., et al. (2023). Temperature dependences of the total spin moment in nanopowders of Ni1-xZnxFe2O4 (x = 0.0, 0.25; 0.5; 0.75; 1.0) ferrospinels. Journal of Superconductivity and Novel Magnetism, 36, 367-371.
3. Ahmadova, Kh. N., Jabarov, S. H. (2023). Obtaining of Al nanosized thin layers and their structural properties. Arabian Journal for Science and Engineering, 48, 8083-8088.
4. Mammadhasanov, K. K., Seyidova, S. A., Ibrahimova, M. D., et al. (2023). Simulation of ionic-liquid extractive purification process of thiophene and m-xylene from their mixture with n-hexane by the molecular dynamics method. Modern Physics Letters B, 37(30), 2350139.
5. Huseynov, H. J. (2021). Study dearomatization of kerosene by IR and UV spectral analysis. Modern Physics Letters B, 35(12), 2150197.
6. Huseynov, H. J. (2021). Selective purification of transformer oil by the method of ionic liquid extractive purification. International Journal on Technical and Physical Problems of Engineering, 13(4), 135-138.
7. Payri, F., Bermúdez, V., Payri, R., Salvador, F. J. (2004). The influence of cavitation on the internal flow and the spray characteristics in diesel injection nozzles. Fuel, 83, 419-431.
8. Safarov, J. (2021). Dielectric constant of methanol over a wide range of temperatures and at high pressures. Advanced Physical Research, 3(2), 75-83.
9. Qi, B., Zhang, Y., Guo, D. (2018). Study on seal performance of injector nozzle in high-pressure common rail injection system. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 40, 97.
10. Zhuravel, D., Samoichuk, K., Petrychenko, S., et al. (2022). Modeling of diesel engine fuel systems reliability when operating on biofuels. Energies, 15(5), 1795.
11. Lazarev, V., Lomakin, G., Lazarev, E. (2016). Modeling of injection parameters for diesel engine injector nozzles with the additional precision guiding interface. Procedia Engineering, 150, 52-60.
12. Namazov, S. N., Mir-Babayeva, S. M. (2015). Simulation of processes of structure formation in the final stage of production of die-rolled-section hardware from steel 20gs at the Baku steel company. Metal Science and Heat Treatment, 57(1), 57-59.
13. Kerimov, R. I., Bakhtiyarli, I. B., Namazov, S. N., et al. (2021). Synthesis and study of physicochemical properties of cast iron with functional properties for working part of bimetallic rolling pins. Chemical Problems, 2, 113-119.
14. Permyakov, A., Nemyrovskyi, Y., Posviatenko, E., Shepelenko, I. (2023). Methodology of technological design in the restoration of parts. IOP Conference Series: Materials Science and Engineering, 1277, 012013.
15. Vasil’ev, V. I., Ovsyannikov, V. E., Nekrasov, R. Yu., Tempel’, Yu. A. (2018). Influence of diffusional surface alloying on the hardened-layer thickness for gray-iron machine parts. Russian Engineering Research, 38, 901-903.
16. Pasternak, V., Zabolotnyi, O., Svirzhevskyi, K., et al. (2022). Influence of mechanical processing on the durability of parts in additive manufacturing conditions. In: Machado, J., et al. Innovations in Mechanical Engineering II. Lecture Notes in Mechanical Engineering. Springer, Cham.
17. Ivanchenko, V. A., Bakulev, V. M. (2017). Manufacturing technology of diamond grinding wheels. Bulletin of the V.N. Bakul Institute of Superhard Materials of the National Academy of Sciences of Ukraine, 1(29), 35-44.
18. Petrenko, A. V. (2019). The influence of diamond grain and concentration on the grinding quality of precision parts. Processing of Materials, 3(45), 52-61.