Via McClatchy
From McClatchy:
Today, BP announced that it has begun using sensitive electronic equipment to detect differences in the rock’s electromagnetic field in an effort to pinpoint the metal pipes inside the wellbore. Based on what they find, they’ll make adjustments every few hundred feet in an effort to intercept those pipes and kill the gusher by pumping it full of tons of heavy drilling mud and then concrete.
The stakes riding on those adjustments are enormous, and the chance of failure, at least on the first try, is huge.
“The engineers will tell you that they have a 95 percent chance of success” in killing a runaway gusher with a relief well, said Bruce Bullock, the director of the Maguire Energy Institute at Southern Methodist University in Dallas. “But that depends on how you define success. It’s quite unlikely they’ll hit it on the first stab.”
“They’re aiming at a salad plate thousands of feet down,” Bullock said: a 7-inch pipe buried in concrete, 12,000 feet below the seafloor.
Every time a relief well misses, its crew must back up the drill bit and try again. Last year, a relief well aimed at capping a blowout in the Timor Sea off Australia* missed its target four times before connecting. Each new effort took an average of another week of drilling, for a total delay of 27 days after the drillers began closing on their target.
A similar delay at the Deepwater Horizon site would mean as much as 1.62 million barrels more crude dumped into the Gulf — more than 68 million gallons — if the latest government estimates of the flow are accurate.
Many obstacles lie in the way of the relief well, not least of which are the same vagaries of subsurface strata and gas pockets that put the Deepwater Horizon 43 days behind schedule before bad decisions and equipment failures sent it to the bottom of the Gulf.
[...]
Uncertainty waits even once the drillers pierce the Deepwater Horizon pipe. That’s when they’ll try to plug the well with drilling mud and concrete. The idea is that the heavy mud will counteract the pressure that’s forcing the oil up the well pipe.
However, such plans have failed before, according to studies of previous relief well attempts, either because the mud didn’t weigh enough or the drillers didn’t have enough of it.
Officials also acknowledge that the plan could be defeated if the well was seriously damaged by the explosion of methane gas that sank the Deepwater Horizon rig and took a mile of pipe down with it.
*That would be the Montara Oil Spill.
The Montara oil spill was an oil and gas leak and subsequent slick that took place in the Montara oil field in the Timor Sea, off the northern coast of Western Australia. It is considered one of Australia’s worst oil disasters.[1]. The slick was released following a blowout from the Montara wellhead platform on August 21, 2009, and continued leaking until November 3, 2009 (in total 74 days), when the leak was stopped by pumping mud into the well and the wellbore cemented thus “capping” the blowout.
And how familiar it all sounds.
A leaking Australian oil well is likely to pour oil into the Timor Sea for nearly two months before it can be stopped, the operator said on Sunday, as environmentalists expressed grave fears for rare wildlife.
Rig operator PTTEP Australasia said it planned to drill a relief well and pour mud to stop the leak, which began on Friday with a blow-out more than three kilometers (two miles) deep.
It would take 20 days to bring a new offshore drilling rig by barge from Singapore, plus four weeks to drill, the company said in a statement.
Asked if this meant the well would flow for nearly two months, a company spokesman told Reuters: “That is pretty much the estimation.”
