Side-track Trajectory Design Optimization in Congested Cluster (Case Study a Pad Containing Seven Wells, Keyi-Field, Block6)

Abstract

To introduce efficiency and cost savings in drilling operations, clients in Sudan have started to focus on Cluster Wells drilling, which is basically the same concept as platform drilling in offshore environment. Multiple wells will be drilled from the same pad structure, which will help clients save rig move time & cost, reduce surface infrastructure and will also help reduce the land acquisition costs. However, as this the first time wells will be drilled in such close proximity, this project thus becomes important for the long-term sustainability of cluster drilling campaigns in Sudan. the Design and Technical Challenges in our case study for pad containing seven wells are 15 meter Center to Center distance (High collision risk), Drilled vertical well in the same pad (Offset Well), Poor survey data for Vertical well, No Gyro Survey available in Sudan, and Difficulties in directional control due to low inclination issue (9 to 20) deg. This project has studied Possibility of Sidetrack trajectory Design in such high dense wells area. COMPASS software has been used for Designing the Pad containing seven wells, side track trajectory from one of the wells (Subject Well) in the same Pad, perform collision risk analysis with regards to the adjacent wells on the same Pad (offset Wells) . Three Side-Track Designing Scenarios has been performed, in first scenario well if kicked-off from 480m, with 2.5 deg/30 m toward 330 deg Azimuth, and turn gradually to 2.76 deg Azimuth. In second scenario well is kicked-off from 530 m, with 3deg/30m toward 100 deg azimuth and turn gradually to 338 deg Azimuth. And in the last scenario well is kicked-off from 950m, with 3deg/30m toward 270deg Azimuth while turning gradually toward 17deg Azimuth. Two scenarios were rejected because based on anti-collision risk analysis tools they were not satisfying design requirements (10-15m), and both scenario were showing high collision risk with offset wells. The third scenario has been selected as optimum Side-track design.