(Update: National Incident Commander authorized integrity test to proceed after 24-hr delay)
OGJ Senior Staff Writer
HOUSTON, July 14 -- BP PLC and a team of federal scientists decided they needed more time for analysis before crews proceed with plans to shut in the runaway Macondo well on Mississippi Canyon Block 252 in the Gulf of Mexico for a well integrity test, spill response officials announced late July 13.
National Incident Commander and retired US Coast Guard Adm. Thad Allen announced the delay, saying additional analysis of the well testing procedure “should be performed before starting the well integrity test.”
Kent Wells, BP senior vice-president of exploration and production, told reporters that the test might start sometime on July 14.
Wells said the delay was prompted by debate by scientists and industry experts about how to interpret pressure readings during the course of the integrity test, which could take at least 6-48 hr.
“We are trying to understand what pressure readings mean over time,” Wells told reporters during a July 14 briefing call. The ideal scenario would be for pressure to build quickly to 9,000 psi once the well was shut in and to hold at that level (OGJ Online, July 13, 2010).
If the well were to be shut in but pressure fails to build to 8,000-9,000 psi at the top of the well, then scientists want to determine at what level within the well that oil might be escaping. Wells said crews would not want oil to be pushed out of the well into shallow zones and leak into the gulf.
If the pressure readings were to reach 6,000 psi or less, Allen said the test would be abandoned. Speaking to reporters during a July 13 briefing, Allen said the difficulty in interpreting the meaning of the pressure readings would come if the pressure were to stall within the range of 6,000-8,000 psi.
Wells said the pressure readings would be taken by transducers that would not be visible in ongoing video taken by remotely operated vehicles and posted on the BP web site.
Relief wells on hold
Wells said the first relief well was at 17,840 ft measured depth, and drilling operations had been paused for the well integrity test. The well is 4 ft horizontally from the Macondo well.
Operations on the second relief well were suspended at 15,963 ft to ensure no interference with the first relief well. “The relief wells remain the sole means to permanently seal and isolate the well,” BP said in a news release.
Until the well integrity test starts, BP continues to ramp up collection operations on the Helix Producer and also continues to use the Helix Q4000, which burns oil using a special burner. The Helix Producer, with capacity to collect 20,000–25,000 b/d, collected 9,200 b/d for the 24 hr ending at midnight on July 13. The Q4000 flares an average of 8,000 b/d.
The sealing cap system, the Q4000 system, the flexible riser system, and the planned additional containment systems never before have been deployed at these depths or under these conditions, and their efficiency and ability to contain or flare the oil and gas cannot be assured. BP said in a news release.
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