Optimizing Electric Submersible Pump Replacement Costs

Abstract

Abstract Electric submersible pumps (ESPs) have made a significant contribution to the petroleum industry as an economic means of artificial lift. As current depressed oil prices linger, it has become especially critical that casts associated with operating ESPs be kept to a minimum. One method, which has resulted in a great deal of success for Amoco Canada, has been qualifying used motors and pumps for re-use through cleaning and testing procedures. Among Amoco Canada's operations are two large fields; the South Swan Hill Unit and the Nipisi Gilwood Unit No.1. Together, a total of 235 electric submersible pumps are in service. As ESPs fail downhole, equipment is examined/or potential testing application. To the end of June 1989, 457pumps have been cleaned and tested while 221 motors have also been put through the test program. A high requalification rate and inexpensive testing cost have combined for substantial savings over traditional repair procedures, The success of the program has been further enhanced by encouraging ESP performance from equipment rerun subsequent to being cleaned and tested. Introduction Amoco Canada Petroleum Company Ltd. is the Unit Operator of two major miscible flood projects. The locations of these fields are shown in Figure 1. The South Swan Hills Unit is located 225 km northwest of Edmonton, Alberta, and comprises ISS producing wells with 70 injection wells. The 124 electric submersible pump locations account for almost 97% of the 30 000 m3 per day average fluid volume. Production is from the Swan Hills formation of the Beaverhill Lake Group, a limestone reef complex. Bottom hole temperature averages 112 °C at a depth of 2 500 m KB. The Nipisi Gilwood Unit No. 1 is located approximately 350km north of Edmonton. The average Unit fluid production is 23 500 m3 per day. Included in the 230 producing wells are 111 ESPs which are responsible for 93% of this volume. An additional 74 wells are used for injection. The producing reservoir is the Gilwood (sandstone) formation at a depth of 1 700 m and BHT of 60 °C. During the Past few years, an average of 125 ESP replacements have taken place annually in the above locations. Included in the $55,000 average replacement cost were ESP equipment expenses of $28,000 each. This resulted in an annual expenditure of approximately $3.500,000 for ESP repair and/or purchase. In April 1987, a used pump and motor testing program was initiated, similar to that described by D.L. Divine(1). In the 26 months since that time, ESP replacement expenditures have been reduced by almost $2 million. ESP Operations Amoco Canada replaces ESPs through me most economic means available. This has historically been with new equipment purchase and/or flat rate repairs. Research into the failures experienced showed that while one component failed, companion equipment was often in good condition and could be re-used. Standby inventories have been maintained separately for each Unit in order to minimize costs and eliminate deferred production due to the unavailability of equipment.