Analyzing Electric Submersible Pump Failures in the East Wilmington Field of California

Abstract

SPE Member Introduction Within the Long Beach Unit of the East Wilmington Field, over 600 electric submersible pumping units (ESP's) are operated from four coastal man-made islands and one pier. In 1984, an ESP quality control program was initiated which ultimately resulted in a significant reduction of ESP failures (Fig. 1). The program required (1) the use of only new rotating equipment in any ESP installation, (2) the testing of all new pumps by the manufacturer, and (3) spot testing of pumps by the manufacturer, and (3) spot testing of the pumps by an independent testing facility to ensure strict adherence to the program requirements. This quality control program continues to be the primary avenue by which an acceptable ESP run-life primary avenue by which an acceptable ESP run-life average is maintained in the Long Beach Unit of the East Wilmington Field. The next step in reducing ESP failures in this field is to determine how the inherent conditions of each reservoir contribute to ESP failure. In so doing, the operating problems that are unique to a certain reservoir condition can be solved. Between January 1, 1985 and March 31, 1989, 1149 ESP's experienced down-hole pumping equipment failure and were subsequently replaced. This case study presents data from the 1149 failures as a function of both the reservoir properties and the pump fluid output and thereby will show the effect of each on ESP failure rates and causes. The extensive number of low volume ESP's utilized in the East Wilmington Field make it a superb area for the study of low volume failure mechanisms. Low volume wells are considered to be difficult to produce with an ESP primarily because of insufficient produce with an ESP primarily because of insufficient cooling of the motor. A minimum fluid velocity past the motor must be maintained to supply adequate cooling. Minimum fluid velocity recommendations, however, vary among ESP manufacturers. These recommendations range from 0.4 ft/s [0-12 m/s] to 1.0 ft/s [0.30 m/s]. Long Beach Unit well producing 1000 bbl/D [159.0 m /D] has a maximum fluid velocity of 0.38 ft/s [0.11 m/s] past the motor and, therefore, fits the low volume criteria. Eighty-six percent of the ESP's included in this study pumped percent of the ESP's included in this study pumped less than 1000 bbl/D. Although ESP's are used successfully in this field e installations producing less than 400 bbl/D [63.6 m3/D] do experience higher rates of failure when compared with the higher volume installations. Thirty-seven percent of the wells in this study produced less than 400 bbl/D yet their ESP produced less than 400 bbl/D yet their ESP installations contributed 53% of the failures. Given the large volume of comparative data available, this study will attempt to provide insight into the causes of both low volume (less than 1000 bbl/D) and extremely low volume (less than 400 bbl/D) ESP failures in the East Wilmington Field. Changes in equipment and operational practices to increase run-life will also be examined. GENERAL FIELD DESCRIPTION The Long Beach Unit of the East Wilmington Field lies under and immediately off the coast of Southern California adjacent to the City of Long Beach (Fig. 2). The productive areas of the field cover 4900 acres [1983 ha]. During the data sampling period (January 1, 1985 to March 31, 1989), approximately 640 ESP-equipped producing wells and 230 injection wells were operating. The Wilmington Field was discovered in the 1930's but development of the offshore portion of the East Wilmington Field was not initiated until 1965 with the construction of the Long Beach Unit oil islands. P. P.