Shifting the Paradigm: ESP with Induction and Permanent Magnet Motor Application in Low Productivity and High GLR Wells

Abstract

Abstract With the imminent decline in gas availability for continuous gas lift operations, Kaji Field, Rimau Block, south Sumatra, Indonesia needed a new lifting method to replace gas lift utilized in marginal wells which produce from Telisa formation (sandstone). This project aimed to evaluate the applicability of electrical submersible pumps (ESP) in wells that are not commonly produced with ESP, and was divided into two phases. The first saw the implementation of an existing ESP with several completion modifications, and the second involved a trial of ESP with the permanent magnet motor system (ESP PMM), which at the time of implementation was a newly applied technology in Indonesia. The alternative artificial lift (AL) configuration had to be operable in wells with low productivity (Productivity Index less than 1 bbl/psi) and have excellent gas handling capabilities (GLR above 3,000 scf/bbl). This presented a stern challenge for the application of submersible pumps due to their basic nature of operating in high liquid rates. Therefore change management also became a crucial agenda in the project. Furthermore, the technology had to be more energy efficient because power generation was also an issue related to the decline in the availability of gas for fueling Kaji's power plants. The first phase saw the installation of the first ESP unit equipped with an induction motor. The low influx and gassy condition of the well was mitigated by setting the pump below perforation to improve pump submergence. A shroud was also utilized to support natural separation of gas before entering the pump intake, and it also helped in creating fluid velocity to provide the motor with sufficient cooling effect. This configuration resulted in excellent productivity within its first one hundred days of production, providing a cumulative oil production equal to twice the amount when produced using gas lift, i.e. from 3,983 to 7,999 barrels of oil within the same time duration. The second phase of the project saw a similar completion strategy in a further two wells, this time with ESP PMM. The result was continuous and safe production, providing a production gain of almost 100 BOPD from the two wells, and with a 100% increase in energy efficiency. This effort has proven ESP's applicability in low influx and high GLR wells, and most importantly has prevented production loss caused by forced shutins from gas lift insufficiency. This provided valuable information for further decisions regarding installations and configurations of artificial lift in Kaji Field and other similar fields, and has allowed us to make the decision to progress further with the transition from gas lift to ESP as the main artificial lift of the field, ultimately supporting the effort to sustain production.