Optimizing ESP Performance in the Kharyaga Field

Abstract

Abstract Total E&P Russie (TEPR) has been operating in Kharyaga field in Komi Republic, Russia, since 1999 under a production sharing agreement (PSA) signed in 1995. Two oil-bearing carbonate reservoirs, Object 2 and Object 3, are produced under the terms of the PSA. The upper Object 3 is pressure supported by an active aquifer. The lower Object 2 was initially produced by depletion before initiating water injection to maintain pressure above bubble pressure. Most of the wells are unable to produce in natural flow and have to be activated. Primarily because of high H2S content, dissolved gas, and wax in the produced oil, well conditions in Kharyaga field are considered harsh for ESP operations. These conditions affected ESP performance and run life, causing premature ESP failures. The project started in 1995 with the evaluation and completion of three existing wells in the Object 2 reservoir. These wells started producing under natural flow in 1999. The phase 2 drilling campaign started in 2001 and completed in 2007 with an increase of the well count by 10 producer and 3 injector wells. Because of reservoir depletion caused by existing production activities, all oil producers were equipped with electrical submersible pump (ESP) systems to help increase overall field production. The pressure support was provided by the adjacent water injector wells. In 2008, TEPR started the phase 3 drilling campaign, which is still ongoing. All 20 producers and 10 injectors drilled to date are equipped with Schlumberger ESPs. Data comparing 2004 to the present shows drastic improvement of ESP performance as a result of the implementation of several ESP design modifications in combination with increased attention to ESP operational procedures and detailed analysis of downhole parameters. As a result of the mutual efforts from TEPR and Schlumberger, the ESP mean time between failures (MTBF) has increased by approximately three times with an overall increase in field production and a reduced number of workovers due to failed ESPs. The average run life of installed ESPs has increased to 1,052 days. Schlumberger has been the company’s supplier for ESP equipment, associated services, and maintenance since 2004, and, in July 2011, services were extended for an additional 3 years.