Pushing the Extended Reach Envelope at Sakhalin: An Operator’s Experience Drilling a Record Reach Well

Abstract

Abstract ExxonMobil, as operator for the Sakhalin 1 project, recently completed drilling operations at the Odoptu Field, located offshore Sakhalin Island, Russia. The Odoptu development drilled nine extended reach wells from shore, culminating with the world record reach OP-11 well. This record setting extended reach well reached a total depth of 12,345 m MD (40,502 ft) / 1,784 m TVD with 11,479 m of vertical section in 60 days with <1% non-productive time. This paper provides a case history of the drilling and completion of the OP-11 well. The major well design parameters that led to the final design will be discussed. Additionally, operational summaries for each hole section will be provided to give an insight on the well construction process. Use of extended reach drilling (ERD) practices has become a common means to economically access reserves from existing infrastructure, provide access to reserves that were previously out of reach, and reduce the environmental footprint of drilling / production facilities. Hence, operators are being challenged to stretch the limits of the ERD envelope, not only from a drilling perspective, but also from a completions perspective. The design for such wells typically employs detailed modeling work; however, a thorough understanding of ERD operational complexities is also required. Over the course of drilling operations at Odoptu, well designs and operational practices evolved to maximize drilling performance while minimizing risks. This paper describes the challenges that were successfully overcome, including wellbore instability, shocks and vibrations, and high torque. Significant OP-11 results include the successful placement of the 9-5/8-in. floated liner at 10,758 m without rotation and the successful placement of completion equipment at world record depth. The operator's use of its performance management workflow successfully reduced downhole shocks and vibrations, optimized hole quality, and resulted in the drilling of each hole section with a single bottomhole assembly (BHA). The design considerations and techniques described in this case history can be used to provide valuable insight for the drilling and completion of future extreme ERD wells. The lessons learned on extreme ERD wells should be thoughtfully considered when designing future wells that stretch the ERD envelope.