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

Abstract

Abstract 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 program1 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 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 average is maintained in the Long Beach Unit of the East Wilmington Field. Fig. 1Recent failure history 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 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]. A Long Beach Unit well producing 1000 bbl/D [159.0 m3/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 less than 1000 bbl/D. Although ESP's are used successfully in this field, the installations producing less than 400 bbl/D [63.6 rrr/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 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 (<1000 bbl/D) and extremely low volume (<400 bbl/D) ESP failures in the East Wilmington Field. Changes in equipment and operational practices to increase run-life will also be examined.