One of the most important problems arising in the construction of wells with a large deviation from the vertical is the need to ensure the stability of the well walls in the intervals of shale deposits drilled-in at large zenith angles. To solve this problem leading world companies offer a number of approaches. These approaches can significantly reduce the risk of complications, but not in all cases it is possible to achieve positive results, and this can lead to significant material losses for oil companies. The PermNIPIneft Branch of LUKOIL-Engineering LLC has developed an integrated technology for complication-free construction of wells with a horizontal termination. This technology includes physico-mechanical studies of subterranean formation properties under reservoir conditions, geomechanical modeling of rock stability, adaptation of drilling fluid composition on the basis of the study of changes in structural and strength properties of core samples under the influence of test fluids, calculation of hydraulic washing program and speeds of tripping operations. This technology successfully passed the pilot tests while drilling a horizontal well at one of the Perm region oilfield. In order to unify the approaches to ensuring the stability of the wellbore with a complex profile for Perm region and Komi Republic, this technology was adapted for the conditions of horizontal wells construction for the Devonian deposits at the Pashninskoye oilfield (Sosnogorskiy district of the Komi Republic). The algorithm of geomechanical rock stability modeling is considered. The results of study on the selection of the components for oil-based drilling fluid are presented in order to ensure the stability of the wellbore in the intervals of Timan-Sargay and Jier deposits. Complex of modern lithological methods, including scanning electron microscopy and X-ray tomography, was used for this study. The efficiency of the developed integrated technology, including geomechanical rock stability modeling and the optimization of the drilling fluid formulation, is confirmed by the results of the pilot tests carried out during drilling a horizontal well at the Pashninskoye oifield.
References
1. Garshina O.V., Predein A.A., Klykov P.I. et al., Geomechanical modeling as an integral part of a complex approach to wells construction in complicated geological conditions (In Russ.), Neftepromyslovoe delo, 2017, no. 5, pp. 28–33.
2. Rybal'chenko Yu.M., Razrabotka promyvochnoy zhidkosti dlya bureniya razvedochnykh skvazhin v oslozhnennykh usloviyakh (Development of the drilling fluid for exploratory wells drilling in the complicated conditions): thesis of candidate of technical science, Moscow, 2009.
3. Nekrasova I.L., Garshina O.V., Khvoshchin P.A., Teoriya i praktika ispol'zovaniya invertno-emul'sionnykh rastvorov v protsesse stroitel'stva skvazhin (Theory and practice of using invert-emulsion solutions in the process of well construction), Perm': Aster Publ., 2016, 148 p.
4. Predein A., Klykov P., Complex approach to well construction with cost minimization in complicated mining and geological conditions (In Russ.), SPE 181938-RU, 2016.
5. Nekrasova I.L., Kazymov K.P., Predein A.A. et al., Change of the composition and texture of terrigenious rocks under the influence of drilling fluids (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2017, no. 6, pp. 37-43.
6. Novikov V.S., Ustoychivost' glinistykh porod pri burenii skvazhin (Stability of clay rocks in well drilling), Moscow: Nedra Publ., 2000, 270 p.
