Slimline High-Speed ESP Application for High Value, Restricted Diameter Wells

Abstract

Electric Submersible Pump (ESP) is the most appropriate artificial lift method for moderate to high production rate wells. However, there are shortcomings in ESP technology for applications in slim casing wells with high rate production potential. These applications include wells in which liners as small as 4 ½′ have been installed inside the original casing for well integrity remediation. Some of these wells can produce high rates, however after the slim liner installation, production in these wells must be curtailed to the maximum production allowed by existing slim ESP technology. In addition to that, performance and reliability of current slim ESP technology is subpar compared with larger diameter ESPs. This paper discusses the development of a new High-Speed High-Rate Slim ESP system that can be installed in casing applications as slim as 5′ and 4 ½′ and it is able to produce higher rates than standard technology. The discussion includes the considerations for the design, the testing plan and the qualification testing results. There are many challenges associated with the design of an ESP to produce high rates in small diameters. This paper discusses mechanical and hydraulic considerations and the evaluation of trade-offs between efficiency, rotational speed and production rate, among others. Since this is a new technology with much higher operating speeds than standard ESPs, there are currently no applicable industry test standards. This paper presents the approach taken to develop the testing and qualification plan, as well as the results obtained during the testing phase. This new ESP technology was demanded to operate under very challenging conditions including tight clearances, harsh environment and high fluid velocities. The testing results showed that the system design met the production requirements while maintaining appropriate levels of performance. The newly high-speed/high-rate slim ESP incorporates multiple innovative design features developed to increase both performance and reliability of the system. Some of these features include a new Permanent Magnet Motor (PMM) design with an advanced control system, a high-frequency variable speed drive, a shaftless protector design, a new slim ESP sensor with high speed data transmission and ground fault capabilities, as well as a new flow/power crossover system with highly reliable electrical connections.