The plan for installing the sealing cap involves a multiple stage process and several vessels and remotely operated vehicles. First, the existing LMRP cap and the remaining riser flange are being removed from the top of the Deepwater Horizon LMRP. Next, a flange transition spool is being installed using the Boa Deep C. Then, using the Discoverer Inspiration, a three-ram capping stack will be connected to the top of the spool.
Because the LMRP cap must be removed to conduct this sealing cap operation, there will be a period of decreased oil and gas capture from the wellhead. During the installation of the sealing cap assembly, the Q4000 should continue to capture and flare oil and gas. Additionally, oil and gas also may be captured by the Helix Producer containment system once it becomes operational. Unlike the LMRP containment cap system, the Q4000 and Helix Producer systems are connected to the kill and choke lines on the BOP via the existing top kill manifold. BP notes that this new sealing cap has not been deployed at these depths or under these conditions, and there can be no assurance that the sealing cap will be successfully installed or installed within the anticipated timeframe. Contingency LMRP caps are positioned on the seabed and it should be possible to return to the current containment configuration if needed.