Improving ESP Production Through Compression

Abstract

ESPs are a main type of artificial lift being used to unload current horizontal unconventional wells. Due to their high cost and high failure rate an operator must implement them in the most efficient manner possible. This paper addresses a way to create a solution to make ESPs more efficient by using compression at surface. Current ways of handling gas through ESPs are insufficient utilizing variable speed drives (VSDs). Additional gas handling equipment installed in ESPs have also encountered mixed results as designs continue to be tinkered to improve gas handling. One area that has not been researched extensively is utilizing compression to drawdown the casing annulus of a well on ESP. A preferential path of less static head pressure allows the gas to be drawn up the annulus rather than handled through the pump. Thereby alleviating gas handling problems in the ESP and raising the FL over the pump. The paper presents two case studies in Oklahoma involving ESP compression assistance up the annulus: one is a case study of an unconventional well of the Mississippi Lime with a low FL and moderate gas production, the second is an unconventional well in the Meramec formation with large amounts of gas production that was increased with the assistance of a compressor to the ESP. Data was collected over a six-week period and ESP performance is compared before and after the surface compressor installation for case 1. In case 2, well performance is compared for 3 different artificial lift setups: gas lift, ESP, and compression assisted ESP over a 3-month period. Both case studies show benefits for utilizing surface compression with an ESP. The biggest benefits were found to be increased production and reduced operating cost by extending ESP longevity.