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Unformatted text preview: According to Transocean, they kept the redline drawings on the Deepwater Horizon and the documents went down with the rig. 154 XIII. BOP Stack Conclusions The Panel concluded that on April 20, 2010, the Deepwater Horizon crew closed the upper annular on the BOP stack at 9:43 p.m. as part of its initial efforts to control the well. At 9:47 p.m., the crew closed the upper variable bore rams as part of their continuing efforts to control the well. When the well blew out, there was a drill pipe tool joint located between the closed upper annular and the closed upper variable bore rams. A.
Cause of the BOP Stack Failure The Panel concluded that there are two possible scenarios for when the BSR was activated. First, the BSR could have been activated by the AMF while the pipe was placed in compression by the upper annular preventer immediately following loss of communication with the rig. Second, the BSR could have been activated by the autoshear on April 22, while the pipe was placed in compression by the we...
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