OGJ Senior Staff Writer
HOUSTON, July 8 -- The relief well being drilled by BP PLC to stop the flow of oil and gas from the Macondo well could penetrate the runaway well in 7-10 days, although the government is standing by an anticipated completion date of mid-August, National Incident Commander and retired US Coast Guard Adm. Thad Allen said on July 8.
The first of two relief wells was at a measured depth of 17,780 ft, Allen said. He did not have a measurement for the intersection depth immediately available. Previously, well operator BP has said Macondo was drilled to about 18,000 TVD.
“When they go to penetrate it, they’ll go through a series of spaces,” Allen said. There are multiple strings of casing and an annulus, a space, between each of them. Allen said it’s possible that oil could be coming up multiple spaces.
The time needed to kill Macondo will be determined by how many times BP might have to pump mud and cement. Allen said crews might also pump cement into an annulus, allow the cement to harden, and then drill through the hardened cement and go into the wellbore.
Once the flow of oil and gas is completely stopped, cement is pumped into the well to plug the well.
The Development Driller III is drilling the first of the two relief wells. An Apr. 20 explosion on the Deepwater Horizon semisubmersible killed 11 workers. On Apr. 22, the rig sank, and oil spill response crews have been working to stop an ongoing spill.
Weather window expected
Allen said he also has asked BP to provide a detailed timeline outlining the process of replacing an existing lower marine riser package (LMRP) containment cap with another cap that would be bolted onto the failed blowout preventer and that would provide a better seal.
“We are in a lull between tropical weather systems,” Allen said, adding that the next week might provide a good time to replace the containment caps. He has been meeting with BP, and a final decision on whether to replace the caps has yet to be made.
“When we go to the second containment cap, this [LMRP] cap will be taken off and replaced with a cap that is actually bolted to a flange, which will give us a seal and the opportunity to completely control the flow of oil and to produce it or potentially shut in the well,” Allen said.
“The issue is, while we are doing that, we will have to remove the Discoverer Enterprise from its current production position,” Allen said of ongoing oil collection efforts. The Enterprise is a drillship. “That will all require good weather to do that, and a number of days to do that.”
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