Oil Spill Containment Efforts Could Be Putting Strain On Damaged Well - NOLA.com

[WillyT]

Oil spill containment efforts could be putting strain on damaged well
Friday, June 18, 2010, 7:57 PM Updated: Friday, June 18, 2010, 8:12 PM
Rebecca Mowbray, The Times-Picayune

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As BP and the government have plotted ways to shut down the renegade oil well in the Gulf of Mexico or contain its spewing oil over the past two months, their options have been limited by concerns about the potential for blowout in the underground portion of the well.

In a well of questionable design with a questionable cement job that's gone through a major explosion, too much pressure on the well, could trigger a rupture, sending oil pushing through fissures in the rock of the ocean floor and bubbling up through the seabed, where it can't be contained.

That's why BP abruptly stopped the "top kill" efforts to seal the well May 28 after the company previously had said the procedure would continue for a few more days. It's also why the company is continuing with efforts to contain the oil flowing out of the well rather than seal the well outright by adding another blowout preventer on top of the malfunctioning one. It's also one reason why the containment cap that's currently capturing oil has vents in the side that allow pressure to escape.

U.S. Coast Guard Admiral Thad Allen acknowledged as much at a briefing Thursday.

"One thing that nobody knows is the condition of the well bore .. . We don't know if the well bore has been compromised or not. One of the reasons we did not continue with top kill at higher pressures, there was a concern that if we increased the pressure too hard it might do damage to the casings and the well bore. What we didn't want was open communication of any oil from the reservoir outside the well bore that might get into the formation and work its way to the sub sea floor and then result in uncontrolled discharge at that point. That has not happened, and that's the reason they're taking such precautions and did not proceed any further with the top kill," Allen said.

"We don't know exactly the condition of the well bore .. .That's the reason we didn't go . . . to excessive pressures on the top kill and decided that we'd deal with containment and then go for the final relief well."

The scenario of oil gushing through the sea floor is considered unlikely, but not implausible. The integrity of the well has become a major topic of discussion among engineers and geologists.

"Everybody's worried about all of this. That's all people are talking about," said Don Van Nieuwenhuise, director of geoscience programs at University of Houston. He said the things that BP has being doing to try to stop the oil or gain control of it have been tantamount to repeatedly hitting the well with a hammer and sending shock waves down the pipe. "I don't think people realize how delicate it is."

"There is a very high level of concern for the integrity of the well," said Bob Bea, the University of California Berkeley engineering professor known to New Orleanians for investigating the levee failures after Katrina, who now has organized the Deepwater Horizon Study Group. Bea and other engineers say that BP hasn't released enough information publicly for people outside the company to evaluate the situation.

Florida Senator Bill Nelson also expressed concern. The Democrat sent BP a letter asking for information and documents relating to any breaks in the well casing beneath the sea floor, any monitoring that BP is doing of the structural integrity of the well, any monitoring of the nearby sea floor for oil leaks, and whether any oil or gas has escaped beyond the boundaries of the casing.

BP spokesman Toby Odone said Friday his company can shed little light on the subject. "We don't know" anything about the condition of the underground portion of the well, Odone said. "We don't know whether the casing inside the well is damaged."

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More: http://www.nola.com/news/gulf-oil-spill/index.ssf/2010/06/oil_spill_containment_efforts.html

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[Ozymanithrax]

1. This news just gets better and beter. n/t

[Bitwit1234]

2. Of course the box didn't work, but could they blast it with

liquid nitrogen and then put the box over it.

[FBI_Un_Sub]

3. Just pump Immodium or Kaopectate into the well ? NT

[Kip Humphrey]

4. If the reservoir fluids reach from reservoir to the subsea outside the well casing

relief wells and bottom kills become worse than useless. Cementing the wellbore at that point simply chokes off one path for the oil/gas to escape the reservoir and increases the pressure and erosive power of fluids escaping the reservoir up through the strata outside the wellbore. The erosive power of such a breach can't be overestimated. It is everyone's greatest fear inside the industry. Said breach would make what has occurred to date seem like the good old days!

[BeFree]

5. Eh?

I thought the relief well would intersect near the bottom of the casing, making everything above that point mute.

Also, isn't the well point just 7 inches?

And... didn't the geologists have a clue of the pressure in the reservoir?
And if they did, how did BP get away with not showing respect for the pressures involved?

[Statistical]

6. Not true.

At least some portion of the earth is non-permeable. If it wasn't the oil formation would never form.

A relief well intersects the main well just about the oil pocket in non-permeable rock.

Like kinking a garden hose with holes in it (damages casing) just above the faucet you render the condition of the hose "downstream" irrelevant.

If done right the concrete plug will be at the same depth as the solid non-permeable rock. Thus oil in the oil pocket has the choice of concrete plug or solid rock.