Improvements and Critical Success Factors for ESP Deployments

Abstract Thirty-nine wells operated by Cabinda Gulf Oil Company (CABCOG) have been completed with electrical submersible pumps (ESP's) on four fields offshore in Angola waters. This paper's focus is on two fields that have different reservoir conditions, well types and lessons learned. The first field came online in 1999. This reservoir is primarily developed with open hole sinusoidal and/or multilateral wells in order to provide sufficient productivity and drainage. The tubing retrievable ESPs (TRESPs) in this field have shown good run-lives despite tubing corrosion and gas slugging. Since 2018 wireline retrievable ESP's (WRESPs) were installed with a jack-up rig on twelve wells. Several retrievable components were replaced successfully using a wireline mast and wireline tractors. The second field came online in 2022 with six WRESP completions. The lower completion consists of production packer, swell packers and sliding sleeves across the open hole reservoir interval. Hydraulic screen technology was used for the three shallower completions for sand control. The upper completion has subsurface safety valve, chemical injection and ESP. Premature failures in 2022 and 2023 and subsequent root cause analysis (RCA) led to an improvement program focused on design, installation and operations of the ESP's. The improvement program the following critical success factors were identified. Troubleshooting using different diagnostic tools, identification of root causes using data and analysis driven process of elimination leading to actions to pinpointed root causes and remedies.Design for current and future conditions and for potential risks that may occur during the ESP life.Rigorous implementation of safeguards and verifying these are in place using SCADA during starts and after shutdowns. Protection from any low flow situation is critical.