Optimized material selection for subsea valves to prevent failure and improve reliability

Abstract

The offshore oil and gas industry began in 1947 when Kerr-McGee completed the first “out of the land” well successfully in the Gulf of Mexico off the coast of Louisiana in just 4.6 m of water. Offshore exploration and production technology have been gradually expanded in the decades since, and the venture for finding oil has moved to deep water areas. Subsea valves are mainly located on the wellhead and manifolds and could be ball, through conduit gate and axial check valves. This paper introduces the main types of subsea valves as well as their main components. The suitable materials for different components have been proposed to increase the reliability through mitigating the corrosion risk, improving the mechanical strength, compatibility with the fluid, maintaining the safe operation of the valve over the design life, etc. The proposed materials are used for critical components of the valves such as body, bonnet, disk, seats, pup piece, etc. and the best choices have been summarized at the end of the table. A chart has been developed introducing the key parameters in selecting the optimized material choice for subsea valves such as erosion, corrosion, HSE, process compatibility, etc.