Adco ESP Pilot

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 101492, "Adco ESP Pilot," by H.A. Hashim, Adco, prepared for the 2006 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 5–8 November. Adco's experience with electrical submersible pumps (ESPs) in deep, high-temperature, and high-gas/oil-ratio (GOR) wells has been discouraging. To ensure that future ESP applications in Adco's mature fields are successful, a comprehensive review was conducted to determine the causes of the previous failures and recommend methods to improve current practices. A multidisciplinary team was created to plan and execute an ESP pilot project. The result of this effort was the successful installation and operation of ESPs in two of the field's oil wells. Introduction The field is in southeast Abu Dhabi and was discovered by a seismic survey conducted in 1959. Crude oil from the reservoir is 42°API with an 850-scf/STB GOR. The reservoir temperature is 250°F. The field has been waterflooded for more than 25 years, resulting in a long history of producing wells ceasing to flow when the water cut reaches 40 to 60%. The long-term solution is to put these wells on artificial lift (AL) such as gas lift (GL) or ESPs. The slow increase in water cuts will change to a much more rapid increase upon fieldwide implementation of the first phase of AL scheduled in 2009. Although GL is seen as the preferred AL method for the field, ESPs could be used as a secondary method. An initial step to the fieldwide AL implementation was to plan an ESP trial with the objectives of restoring production and accelerating data acquisition on well and reservoir performance at higher water cuts to refine field-development plans. The wells selected for the ESP project were three oil producers that had ceased to flow because of a high water cut. Because of mechanical-integrity problems with one of the wells, only two ESPs were installed. Adco ESP Review Although ESP performance in water-production wells and shallow oil wells is impressive, performance in deep and high-temperature oil wells has been beleaguered by a number of premature failures. To ensure that future ESP applications in these fields are successful, a comprehensive review was conducted to determine the causes of the previous failures and incorporate the findings into new designs and procedures for the pilot tests. After analysis of the past ESP experiences, the review team agreed that all past failures could have been prevented if attention had been paid to detail. The failures in the past were primarily the result of wellbore pollutants and debris; poor manufacturing, quality assurance, and quality control; and installation practices.