No abstract

Electric submersible pumps (ESPs) are considered to be a very cost effective artificial lift method by industry standards, particularly in water supply wells (WSWs). In four WSWs, ESP performance had experienced a number of premature failures, which resulted in short average run lives of less than 1 ½ years, high operating costs, and unsustainable water supply required for injection pressure support and field development. To ensure that future ESP application in these wells is successful and improve run life, a multidisciplinary team was formed and conducted a comprehensive review to identify the causes of previous ESP failures and recommend methods to improve current practices based on all gathered engineering data; including, dismantle results of pulled ESP units, well and reservoir data, completion strategy, ESP equipment design, commissioning, and data monitoring. The analysis indicated that the failures were primarily the results of corrosion and solids, and lack of close monitoring of ESP performance review, which prevented rectification of the problems in a timely manner. Secondary problems were also identified, such as tight wellhead clearance that damaged wellhead penetrators during installation, failure of tubing internal coating, and insufficient wellbore cleanout before making up ESPs during workovers, etc. This engineering approach has successfully helped to increase confidence in, and reliability of, ESP operations, optimization, sustained field production levels, and reduced capital and operating costs due to improved pump run life. This paper reviews the performance of ESP systems in WSWs and the challenges faced during the past 4 years of operation. Also, it covers installations, commissioning, dismantle inspection failure analysis (DIFA) results, operation philosophy, optimization methodology, average ESP run life, and ESP technical improvements.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe majority of the PWI wellheads injection trees in the Ghawar field have already passed their half-life time designated by the manufacturer and others have even completed their life cycle. Several operating factors were considered during the initial design stages of these trees based on the operating circumstances. The alloy (steel) of the PWIs composite trees have been selected to cope with the anticipated flow media, such as seawater, high injection pressures and rate (3,000 psig), frequent valve cycling and the life lasting expectancy was set for 20 years.Nowadays, despite frequent valve care maintenance through the ongoing valve care program, the integrity of these valves has become susceptible to failure more than ever. The failures are caused either internally due to seats ring and ball damage, or externally due to flange leaks due to "O" rings and groove damage. In addition to the harsh operating conditions, aging is also another major cause for valves' integrity deterioration.The innovative idea is to utilize synthetic valve care sealants to temporarily stop valve internal leaks (internal passing) by injecting a sealant through the ball valve's upper and lower grease fittings that are directly related to valve seats and sealing area, Fig. 2. The dual function of the lubricants/sealants is to clean hard deposits4, lubricate sealing elements and fill-in the internal channels and grooves. By doing so, the seats get pushed against the ball valve body sealing area, resulting in 100% pressure seal from both directions. The above stated idea is in use now as we speak, and has proven its practicality in the field to resolve valve leakage issues and make job executions arrangements simple and cost-effective.