Enhancing Subsea Ball Valve Performance: A Material and Design Approach

Subsea field development is an important aspect of offshore oil and gas operations. One of the key components in the production system is the subsea actuated valves, installed on Christmas trees and manifolds to control the produced fluid flow from the well to the manifold, and then to onshore facilities or vessels. With the shift towards All Electric Control Systems (AES) in subsea operations, ball type subsea valves could be seen as a better fit for electric actuation since they operate with rotational movement, which aligns well with electric actuation mechanisms, eliminating the need to convert rotational movement to axial movement as in rising stem gate type valves. However, with the current use of tungsten carbide (WC) based coatings on the contact surfaces and sealings, the friction forces, and consequently the required power for actuation, are quite high. This leads to an extended valve opening duration which exposes the internal parts, especially the seals, to solid particles in the fluid. This results in a high wear and damage rate of the valve components over time and eventually the risk of sealing failure. Initial lab tests from ongoing research activity on enhancing the material and coatings of the contact surfaces have shown a promising coefficient of friction of 0.08. To quantify the possible force and power reduction through material innovation, a 3D model of the 12-inch subsea ball valve is created, and the model includes different variations of the valve designs depending on the seat type. The models are exposed to different pressurizing scenarios and the maximum torque values are determined through finite element analysis. Considering the safety margins, the results show that with the material enhancement the design torque is expected to be reduced by around 25–35% depending on the valve design. This optimization contributes to the transition to AES in subsea operations by addressing the challenges resulted by high power requirements of subsea ball valves.