OGJ Senior Staff Writer
HOUSTON, Sept. 17 -- A relief well drilled by crews on Transocean Ltd.’s Development Driller III semisubmersible intercepted the annulus of the deepwater Macondo well on Sept. 16, and BP PLC expects crews will completely seal the Macondo well on Sept. 18.
Engineers and scientists from across the oil industry have worked with government scientists for months to reach this point. An Apr. 20 blowout of the Macondo well in 5,000 ft of water and subsequent oil spill prompted the development of new technology and equipment to handle a seabed spill.
An estimated 4.9 million bbl leaked from the well, of which BP estimates it captured 800,000 bbl. No oil has leaked into the gulf since a capping stack was installed on July 15. BP operates the well on Mississippi Canyon Block 252 off Louisiana.
The Macondo well blowout triggered an explosion and fire on Transocean’s Deepwater Horizon semi, which killed 11 people. The Deepwater Horizon sank on Apr. 22. Cause of the accident remains under investigation by a number of government agencies and others.
After replacing the Deepwater Horizon’s failed blowout preventer earlier this month, relief well drilling resumed at 7:15 a.m. CDT on Sept. 15, and crews completed drilling the final 45 ft of hole. Interception of the annulus was confirmed at 4:30 p.m. on Sept. 16. Total measured depth on the DDIII for the annulus intercept point was 17,977 ft.
“Operations conducted bottoms up circulation, which returned the contents of the well’s annulus to the rig for evaluation,” BP said. “Testing of the drilling mud recovered from the well indicated that no hydrocarbons or cement were present at the intersect point. Therefore, no annulus kill is necessary, and the annulus cementing will proceed as planned.”
Once cementing operations are complete, the DDIII will begin standard plugging and abandonment procedures for the relief well.
The Development Driller II semi continues gathering additional data from the Macondo well in efforts to determine the location of the drill pipe in the well during the Apr. 20 accident. DDII’s BOP is latched onto the wellhead.
Subsequently plug and abandonment activities will commence in accordance with the approved procedure, BP said.
National Incident Commander and retired US Coast Guard Adm. Thad Allen issued a news release late Sept. 16 saying he received extensive briefings over the last 24 hr as BP engineers and federal scientists confirmed the relief well intersected the Macondo well.
“The aggregate data available supports the conclusion that the two wells are joined,” Allen said. “It is also important to note that none of the measurements supported a scenario where the annulus of the well is in communication with the reservoir. Accordingly, we intend to proceed with preparation to cement the annulus and complete the bottom kill of the well.”
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