Improving ESP Performance with Two Stages of Gas Separation in 7 Casing Case Study

Abstract

Abstract The Electrical Submersible Pump (ESP) has become one of the most popular ALS worldwide due to its capacity of lifting high fluid volumes with high efficiency, however, its application is questioned under some circumstances related to difficulties that this system presents when managing high gas rates. Even though the ESPs can handle high volumes, they are also highly affected by gas bubbles flowing through each component, affecting: the motor temperature, lifting efficiency, the integrity of the motor and cable, situations that can lead to premature failure and expensive workover operations. This is the reason why some companies decide to install a different ALS instead of an ESP. The present study shows a successful ESP optimization in combination with a new gas mitigation system that allowed to manage high GOR and GLR and avoid gas locking, low lifting efficiency, multiple shutdowns due to poor cooling in the motor, and surge production (changes on motor load). The new double stage gas mitigation system was designed to manage a GOR>1,200 SCF/STB with a WC of <1%, BHT of 200 °F, and 85% of free gas flowing into the pump intake. This gas separation system for ESP was complemented by installing a shrouded ESP to assure a proper cooling of the motor and to prevent the free gas to flow directly to the pump intake. This paper contains all the descriptions of each component of the 2 stage gas mitigation/separation system. The well showed a notorious production improvement and the operator was able to decrease the PIP below 630 psi (Max limitation on the Jet pump system due to low efficiency of this ALS) achieving a production increase from 300 to 700 BOPD (↑400 BOPD)