A Holistic Approach to Improving ESP Reliability and Energy Efficiency at Van-Yogan Field

Abstract

The paper describes the methodology and specific action items developed and applied jointly by the operating company and contractor teams to achieve significant improvements in reliability (run life) and reduce power consumption in more than 300 artificially lifted wells equipped with electric submersible pumps (ESPs) in the harsh environment of Van-Yogan field in Russia, Western Siberia. The extended duration of the project, which started in January 2012 and is currently ongoing, offers a unique opportunity to review and analyze the longer-term contribution and efficacy of the various methods presented. To date, the project has delivered consistent improvements in both energy efficiency and equipment reliability, translating to substantial savings in the lifting costs for the operator. Average pump efficiency increased by 4.3 percentage points (from 60.4% to 64.7%), which is an excellent result considering the average pump flow rate decreased from 240 m3/d to 182 m3/d during the same period due to overall aging of the field. It is widely known in the industry that smaller pumps generally return lower power efficiency figures; therefore more efficient novel pump designs and operating procedures had to be introduced to facilitate this efficiency improvement. Despite continuously deteriorating well conditions under the adverse influence of scales, corrosion and production of high volumes of free gas and solids through the ESP, average pump run life was extended by 101 days since the project start date (from 335 days at the beginning of 2012 to 436 days at the end of 2015, or by more than 30%). At the same time, Mean Time Before Failure (MTBF) improved by more than 56% over the same period (from 511 to 796 days), decreasing workover costs and deferred production. The comprehensive approach includes accurate ESP selection to better match well conditions, use of high-efficiency ESP pump and motor designs, flawless field service execution, and continuous monitoring and fine tuning of equipment performance. Inspection of dismantled equipment and failure root cause analysis (RCA) plays a fundamental role to ensure that adverse well factors are properly addressed by ESP design and operating procedures.