The Evolution of Geomechanics Application in the Korchagina Field, North Caspian Sea

Abstract

Production from the periphery of the Korchagina field, a pilot project of Lukoil for offshore development in the Caspian region, is only possible by drilling extended reach (ERD) wells, with extreme lengths of lateral sections exceeding 6 km. The tough geological environment and uncertainties in wellbore stability conditions require real-time updating of the model during drilling, which has helped to update collapsed gradients and optimize mud properties, hole cleaning, and tripping procedures. Implementation of improved geomechanical modeling has led to the successful drilling of a challenging 12.25-in. section after two failed boreholes. Adding 3D calculations to the models demonstrated that with the existing well and casing design, safety was a major factor in wellbore design. The 3D models led to changes throughout the well design. As a result, applying geomechanics in the Korchagina field has produced outstanding results. So far, 21 wells have been successfully drilled with minimal borehole instability issues, including record ERD Wells 103 (TD 8001 m) and 108 (TD 8005m).