High-Power ESP Tubing-Hanger Connector for Deepwater Downhole Applications

Abstract

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 24138, ’Reliable High-Power ESP Tubing-Hanger Connector Systems for Deepwater Downhole Applications,’ by Sami Spahi, Teledyne Oil and Gas, and Pamela Parsley, Chevron Energy Technology Company, prepared for the 2013 Offshore Technology Conference, Houston, 6-9 May. The paper has not been peer reviewed. Reliability of subsea equipment is an indispensable requirement in deepwater applications. Tubing-hanger (TH) -connector systems can be a critical failure mode for electrical submersible pumps (ESPs) in high-pressure/high-temperature (HP/HT) environments. Through use of reliability tools such as fault-tree analysis (FTA), failure-mode effect and criticality analysis (FMECA), and systems reliability block diagrams (RBD), it was established that improving the reliability of the TH-connector system has a direct effect on the unintervened life of the ESP electrical system. Project Basis of Design A joint development project between the operator and the connector-system supplier focused on the design, installation, and intervention of downhole ESPs in deepwater subsea wells in the Lower Wilcox developments in the Gulf of Mexico. The system design encompasses the ESP completion, subsea wellhead, tree, TH, and power and control system. The system design criteria are for 8,000-ft water depth and a 14-mile tieback (Fig. 1). Connector-System Reliability Overview At the start of the project, the operator, the connector-system supplier, and other equipment vendors met and agreed to align their reliability plans. Common reliability tools, including FTA, FMECA, and systems RBD, help all collaborators to have a better understanding of the relationship and sensitivity between subsystem reliability and the unintervened life of the ESP electrical system. FMECA. The FMECA process is typically performed by the present multiple teams to capture different backgrounds and benefits for a wider range of feedback. In this process, each component and subsystem is considered and its corresponding functions are identified. The purpose is to consider the conceivable failure modes associated with each component and function on the basis of prior art, knowledge, and industry experience and then develop plans to mitigate such failure modes in a hierarchy that is based on the criticality.