Optimization Delivers ERD Performance Boost - Sakhalin Island

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 150959, ’Successful Optimization Strategies Combine To Deliver Significant Performance Boost at the Edge of the ERD Envelope-Sakhalin Island, Russia,’ by Richard W. James, SPE, Paul Pastusek, SPE, and Gary R. Kuhn, SPE, ExxonMobil; Anton Andreev, Exxon Neftegas; and Jeffrey R. Bailey, SPE, and Lei Wang, SPE, ExxonMobil, prepared for the 2012 IADC/SPE Drilling Conference and Exhibition, San Diego, California, 6-8 March. The paper has not been peer reviewed. Many performance-enhancement initiatives were used by the operator of the Sakhalin-I project in drilling and completing the extended-reach-drilling (ERD) program at the Odoptu field, Sakhalin Island, Russia. The initial seven-well ERD program was expanded to nine wells, including the world-record Well OP-11. The operator’s redesign philosophy to remove limiters from the drilling process resulted in significant performance improvements in all areas of drilling and completion operations. Background The Odoptu field is one of three fields developed by Exxon Neftegas off the coast of Sakhalin Island, Russia, as part of the Sakhalin-I Project (Fig. 1). The climate is subarctic, with temperatures lower than freezing more than half of the year, and temperatures can drop below −40°C. The field is at the northeastern edge of the Eurasian tectonic plate and is subject to significant earthquake activity, the most recent of which was rated 7.6 on the Richter scale in 1995. Drilling began in the Chayvo field in 2003, following mobilization of the Yastreb rig to the Chayvo onshore well-site. After drilling one cuttings-injection well and 20 ERD wells, the Yastreb rig was upgraded and moved to the Odoptu North wellsite in late 2008. Drilling commenced from the Chayvo offshore well-site with the installation of the Orlan platform in 2005, where an additional cuttings-injection well and 19 ERD wells were drilled. During the move from Chayvo to Odoptu, significant upgrades were made to the rig on the basis of lessons learned at Chayvo and to accommodate the higher torque anticipated at Odoptu. The new topdrive could deliver 91,000 lbf-ft of torque at 130 rev/min. A larger mast was required to accommodate the new top-drive, and an additional generator was installed. The drillstring was upgraded to provide significantly higher torque capacity. In addition, the handling capacity of the cuttings-injection unit was increased. Drilling began at Odoptu in April 2009 (with the cuttings-injection well) and ended in February 2011 (with completion of Well OP-2). Although seven ERD wells were planned at Odoptu initially, the program was expanded to nine wells as a result of drilling successes and favorable production performance. The wells included Well OP-11 with 12 345-m measured depth (MD) and 11 479-m horizontal reach. The Yastreb rig has drilled more than 300 000 m of hole. Following the Odoptu program, the Yastreb rig was moved back to the Chayvo onshore well-site to drill additional ERD wells.