Vol. 337 No. 2 (2026)
DOI https://doi.org/10.18799/24131830/2026/2/4902
Method for determining a drilling tool eccentricity for drilling anisotropic rocks
Relevance. Need to solve the problem of effective well drilling in a given direction in solid anisotropic rocks. Aim. To develop a methodology for selecting the parameters of a diamond drill bit for effective well drilling in a given direction in solid anisotropic rocks. Methods. Analytical studies, experimental work and experimental drilling of wells in conditions of natural curvature of wells. Results and conclusions. The authors have developed a method for calculating the parameters of the armament of a diamond crown with an optimal eccentricity of the armament of the end face to solve the problem of conducting a well with minimal curvature in anisotropic rocks. The value of the eccentricity of the armament of the diamond crown should be set taking into account such parameters as the degree of rock anisotropy and the angle of meeting of the drilling tool axis (the axis of the drilled well) with the stratification, layering-shale of the anisotropic rock. To determine the optimal value of the eccentricity of the armament of a diamond crown for drilling anisotropic rocks with minimal curvature of the trunk, it should be performed in the following way: it is necessary to calculate the magnitude of the destabilizing forces in accordance with the proposed analytical dependencies, including the anisotropy parameter of the rock, the values of the ultimate chipping strength, the coefficients of friction along and across the stratification-shale of the rock, the depth of penetration of incisors into the rock moving towards and along the stratification-shale; the calculation of the magnitude of the eccentricity must be performed taking into account the fact that the imbalance of the cutting-chipping force of the rock being developed by the crown should be equal to the value that destabilizes the uniform rotation of the crown from the anisotropic rock.
Keywords:
rock, rock anisotropy, drilling, diamond crown, destruction
References:
1. Krivosheev V.V. Well curvature in anisotropic rocks. Tomsk, NTL Publ. House, 1999. 240 p. (In Russ.)
2. Bredley W.B. Formation characteristics have a key effect on hole direction. Oil and gas J, 1975, vol. 73, no. 31, pp. 77–80.
3. Bonnar R., Panagapko O.A., Williams G.I. Deep deflection corehole. Engineer and Mining J, 1985, no. 8, pp. 26–30.
4. Boyarko Yu.L. Combating well curvature. Tomsk, TPI Publ. House, 1969. 110 p. (In Russ.)
5. Riley L., Swarts H., Anderson M., Large diameter bi-center bits and drilling casts. Petroleum Engineer International, 1990, August, pp. 25–30.
6. Boning G., Iezierski H., Pitz W., Sohlocbaoch M. Steueuung horizontaler Kernbohrungen grosser lange im Salzgestein. Erzmetall, 1984, no. 5, pp. 8–11.
7. Deveraux S. Drilling technology in nontechnical language. 2nd ed. Tulsa, PennWell Books, 2012. 370 p.
8. Holbert D.R. Now interest in drainhole drilling revives technology. World oil, 1981, no. 4, pp. 7–10.
9. Holbert D.R. How rotary speed affect bits trajectory. Drilling Contractor, 1986, July, no. 7, pp. 92–94.
10. Williams G.I. Operation experience with wireline technique. Geodrilling, 1986, June, no. 7, pp. 7–10.
11. Morozov Yu.T. Drilling of directional and multilateral small-diameter wells. Moscow, Nedra, 1976. 211 p. (In Russ.)
12. Kolesnikov A.E. Well deviation. Moscow, Nedra Publ., 1979. 176 p. (In Russ.)
13. Bogolyubsky K.A., Zinenko V.P., Kirsanov A.N. The process of natural curvature of rotary drilling boreholes in an anisotropic medium. News of Higher Education Institutions. Geology and Exploration, 1974, no. 3, pp. 110–116. (In Russ.)
14. Zinenko V.P. Directional drilling. Moscow, Nedra Publ., 1990. 152 p. (In Russ.)
15. Neskoromnykh V.V. Directional drilling and basics of core measurement. 3rd ed., suppl. Krasnoyarsk, SFU Publ. House, 2022. 448 p. (In Russ.)
16. Karpikov A.V. Scientific and methodological principles of controlling the intensity of natural borehole curvature. Cand. Diss. St Petersburg, 2002. 179 p. (In Russ.)
17. Budyukov Yu.E., Vlasyuk V.I., Spirin V.I. Diamond tool for drilling directional and multilateral wells. Tula, ZAO "Grif i Ko" Publ., 2007. 176 p. (In Russ.)
18. Kozlovsky E.A. Diamond crown for drilling tool assembly. Patent Russian Federation, no. 2078193, 1997.
19. Neskoromnykh V.V., Popova M.S., Liu Baochang. Destruction of rocks during drilling of wells with a diamond drill. Krasnoyarsk, SFU Publ. House, 2020. 268 p. (In Russ.)
20. Huang W., Gao D. Analysis of drilling difficulty of extended-reach wells based on drilling limit theory. Pet. Sci, 2022, vol. 3, pp. 1099–1109.
21. Harrypersad-Daniel A.M., Blake O.O., Ramsook R. Compressive and tensile strength anisotropy of friable sandstone and thin-bed shale of the Pleistocene Erin formation: insights for safe operating mud weight windows for vertical and horizontal wells. Pure Appl. Geophys, 2023, vol. 180, pp. 4191–4218. DOI: https://doi.org/10.1007/s00024-023-03384-x.
22. Yang Quan-zhi. Engineering solution for variable curvature trajectory design of extended reach well. Available at: https://link.springer.com/chapter/10.1007/978-981-99-2649-7_33 (accessed: 1 November 2023).
23. Neskoromnykh V.V. Curvature of wells in anisotropic rocks. Krasnoyarsk, SFU Publ. house, 2017. 204 p. (In Russ.)
24. Neskoromnykh V.V., Petenev P.G., Ivanov D.S. Fundamentals of designing drilling tools with eccentric end-face cutting structures for drilling anisotropic rock formations. Construction of Oil and Gas Wells on Land and Offshore, 2024, no. 2 (374), pp. 63–69. (In Russ.)
25. Neskoromnykh V.V., Petenev P.G., Neverov A.L. Development and experimental studies of the performance features of a diamond crown for drilling in hard anisotropic rock formations. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2018, vol. 326, no. 4, pp. 30–40. (In Russ.)
26. Spirin V.I., Budyukov Yu.E., Neskoromnykh V.V., Petenev P.G. Diamond core bit for drilling. Patent RF, no. 148333, 2014. (In Russ.)
27. Neskoromnykh V.V., Petenev P.G., Popova M.S., Lysakov D.V., Ivanov D.S. Diamond core bit. Patent RF, no. 213987 U1, 2022. (In Russ.)
28. Neskoromnykh V.V., Petenev P.G., Popova M.S., Sayapin A.A., Ivanov D.S. Diamond core bit. Patent RF, no. 214917 U1, 2022. (In Russ.)
29. Neskoromnykh V.V., Petenev P.G., Volchatov A.S. Diamond core bit. Patent RF, no. 227267 U1, 2024. (In Russ.)
30. Neskoromnykh V.V., Petenev P.G., Popova M.S., Sayapin A.A., Ivanov D.S. Diamond core bit. Patent RF, no. 214925 U1, 2022. (In Russ.)
