CBP: Open-Water Contingency Barrier Plug for XT Annulus Valve Block Leakage

Leakage in the XT annulus valve block is a well-documented risk on subsea Christmas trees, particularly as equipment ages and production pressure declines, with corrosion, erosion, and wear degrading seals and valve components over years of service. CBP, is an open-water intervention tool designed specifically to respond to this scenario. As a Contingency Barrier Plug, CBP is installed in open-water and seals on the inside of the HXT re-entry hub, providing a barrier when leakage occurs on the XT annulus valve block, typically when production pressure is low. This enables rapid response and mitigation without requiring a full system shutdown. CBP is installed in open-water, operated by the ROV and run overboard using a subsea crane or winch, and can be configured for different HXT systems. Once installed, it can be retrieved either in open-water or, where the well barrier situation requires it, pulled through the BOP and Work Over Riser from the rig, giving operators flexibility in securing well control during intervention operations. By enabling a fast, ROV-deployed response to annulus valve block leakage, CBP helps operators avoid unnecessary production downtime while keeping the option of a rig-based approach available whenever well control considerations call for it.