OGJ Senior Staff Writer
HOUSTON, Aug. 16 – The National Incident Commander for the oil spill response asked BP PLC, operator of the deepwater Macondo well, to continue taking pressure readings in the blowout preventer and the capping stack and to gather more information before proceeding with a relief well to seal the well from the bottom.
Retired US Coast Guard Adm. Thad Allen instructed BP to provide government scientists with an analysis of the risks associated with the annulus and any risk s that might cause “communication between the reservoir and the annulus.”
Allen said he wants BP to establish a plan so that it could relieve pressure if it starts to build during the bottom kill, which will be done by pumping heavy drilling fluid and cement into the Macondo well.
BP must outline “options on how we could conduct some kind of a pressure relief procedure—relief valve or something like that on the capping stack,” Allen said. Meanwhile, he requested “full readiness” of Transocean Ltd.’s Development Driller III semisubmersible, which is drilling the relief well.
Eventually, the failed Deepwater Horizon semi’s blowout preventer is to be removed. Allen said that before that happens, BP must “prove to my satisfaction that the Macondo annulus does not represent a potential pathway for hydrocarbon flow.”
Allen asked BP to identify the conditions under which flow could occur and to analyze the risks of that happening. BP estimates the annulus could contain 1,000 bbl of oil.
“We are still dealing with part of the well that we can’t see and only know from pressure readings and external indications,” Allen said, adding the condition of the annulus cannot be known for certain until the relief well intercepts the Macondo well.
Allen said he expects to give a directive to go ahead with the bottom kill, subsequent to the test and investigation that he requested in an Aug. 14 letter to BP. He estimates it will take 4 days to intercept the well following a directive to proceed with the intercept, but he declined to estimate on the timing of when he might issue that directive.
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BP, government analyzing pressure risks in Macondo well