Relief wells delayed over fears of a new spill
17 August 2010
As of Monday, BP had yet to resume drilling of two relief wells which aim to permanently seal off its Macondo well. The latest delay arose over concerns that the operation might create a new spill.
It had been widely reported that the completion of the relief wells would begin on Tuesday, but National Incident Commander Thad Allen cast doubt on that in a Monday press conference. “Timelines won’t be known until we get a recommendation on the course of action,” Allen said, adding that the process “will not start until we figure out how to manage the risk of pressure in the annulus.”
The annulus is a ring that surrounds the well’s casing. Last week scientists found evidence to suggest the annulus was breached during the “static kill” operation in late July, during which heavy mud and cement was used to force oil back down toward its reservoir.
In the procedure, oil very likely became trapped in the annulus between the seafloor and the reservoir. This has raised concerns over how to maintain a safe pressure level when the relief well intersects the Macondo and the “bottom kill” of pumping cement into the lower reaches of the well can begin.
Some engineers have criticized the decision to use the static kill prior to the completion of the relief wells. “It would have been easier and safer to kill the well with the relief well,” Les Ply, a retired petroleum engineer, told Bloomberg.
It cannot be excluded that the relief well may cause a new blowout or in some other way open up an avenue for the oil to escape its reservoir, estimated at a volume of between 2 billion and 4.2 billion gallons—20 and 40 times the magnitude of the Deepwater Horizon blowout.
To control pressure in the well casing, two procedures are reportedly being debated. One would involve removing the new capping stack, placed over the wellhead on July 15, and replacing it with another blowout preventer. Another possibility would involve BP creating a new pressure relief device for the capping stack now in place.
Whatever the risks, no confidence can be placed in either BP or the Obama administration. From the beginning the response, cleanup, and efforts to contain the well have been animated by one overriding concern—the defense of BP and the oil industry as a whole.
The Macondo erupted in the biggest sea blowout in history on April 20 after BP ignored a series of warnings and unsafely expedited well-capping with its exploratory Deepwater Horizon rig. Eleven workers died in the resulting explosion and upwards of 200 million gallons of oil were dumped into the Gulf of Mexico by mid-July.
In its efforts to contain the gusher BP moved from failure to failure—“top hat,” “containment dome,” “junk shot,” “top kill,” and so on. All through the process, however, BP maintained that the ultimate and fail-safe means for finally closing off the Macondo would be through the drilling of relief wells that would intersect with it far below the seabed and plug the well by pumping cement into it.
But in mid-July BP abruptly suspended drilling of the relief wells, even though one of the two was reportedly within feet of the Macondo. It then put in place a new capping system, ostensibly to conduct a 48-hour pressure test. Even though the pressure test failed to achieve the results BP had said were necessary, the cap was left in place permanently. This was followed by the static kill operation.
No rationale was provided for the suspension of the relief wells in July. This was in keeping with the modus operandi of BP and the Obama administration throughout the disaster: cover-up.
The mysterious stop-and-go of relief well drilling continued last week. After bad weather temporarily suspended drilling early in the week, BP intimated that it would not be necessary to complete the relief wells at all.
“After all this effort, why would they quit before they’re done?” asked Richard Charter, an analyst with Defenders of Wildlife. “If you had a trustworthy company and they said it’s done, it’s done. But in this case BP has not been a trustworthy company.”
Then on Friday Allen publicly declared that the relief wells would be completed. “The relief well will be finished,” Allen said. “We will kill the well.”
When this might take place has been thrown into doubt by the discovery of the breach in the annulus.