Jul 12: A BP release explains that following a technical review last week, the National Incident Commander Thad Allen, on July 10, approved BP's plan to move ahead with replacing the existing lower marine riser package (LMRP) containment cap over the Deepwater Horizon's failed blow-out preventer (BOP) with a new sealing cap assembly. The new sealing cap contains three closing rams and multiple ports for connection to additional containment options. The new cap creates the potential to increase oil and gas containment capacity to greater than 50,000 barrels per day and should improve containment efficiency during hurricane season by allowing shorter disconnect and reconnect times. The new cap assembly also might simplify future well kill and cementing procedures through the relief wells, which in turn could increase the probability of success for those operations. In addition, the new cap should enable a shut-in test to be performed to determine integrity of the MC252 well.
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.
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.
The sealing cap operation began over the weekend to take advantage of anticipated favorable weather conditions and is expected to take between four and seven days to complete. The sealing cap installation procedure is intended to run in parallel with the installation and start-up of the Helix Producer containment system, which was expected to begin ramping up containment operations as early as Sunday.
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.
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.
BP also indicated that work on the first relief well, which started May 2, has reached a measured depth of 17,810 feet on July 9. The previous ranging run indicated that the relief well is now approximately 5 to 7.5 feet horizontally away from the MC252 well. The next planned step is to do another ranging run and then drill down 30 feet to a measured depth of 17,840 feet. The series of drilling and ranging runs will continue for approximately another 60 feet. The 97/8 inch liner will then be set before beginning the final series of drilling and ranging runs before intercepting the MC252 well. Although uncertainty still exists, the first half of August remains the current estimate of the most likely date by which the first relief well will intercept the MC252 well and kill operations performed. The second relief well, which started May 16, is drilling at 15,963 feet. The next planned step is to set the 117/8 inch casing. Following casing and cementing, the second relief well will pause to avoid any interference with the first relief well activities, but be positioned should any issues arise with the first relief well.
BP also reported that on July 10, a total of approximately 15,200 barrels of oil were collected or flared and 35.2 million cubic feet of gas were flared. For the first 12 hours on July 11 (midnight to noon), approximately 4,035 barrels of oil and 9.8 million cubic feet of natural gas were flared on the Q4000. With the removal of the LMRP cap, oil recovered from the Discoverer Enterprise was lower on July 10 and recovery from the Discoverer Enterprise has since been discontinued.
The Unified Command reported that in anticipation of increased oil flow following the removal of the top hat containment device, skimmers were surged to the well site -- allowing crews to take advantage of good weather conditions and skim an estimated 25,500 barrels of oily water, double the amount collected the previous day. Currently, 46 skimmers are operating in the vicinity of the well, in addition to more than 570 skimmers deployed to protect coastlines as part of the largest oil spill response in U.S. history.
Access BP's release on the installation of the new cap (click here). Access the new RestoreTheGulf website for links to the latest Unified Command updates and more (click here). Access the latest BP update (click here).
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