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Did Deepwater Methane Hydrates Cause the BP Gulf Explosion?

Strange and dangerous hydrocarbon offers no room for human error

By David Sassoon

May 19, 2010

The vast deepwater methane hydrate deposits of the Gulf of Mexico are an open secret in big energy circles. They represent the most tantalizing new frontier of unconventional energy โ€” a potential source of hydrocarbon fuel thought to be twice as large as all the petroleum deposits ever known.

For the oil and gas industry, the substances are also known to be the primary hazard when drilling for deepwater oil.

Methane hydrates are volatile compounds โ€” natural gas compressed into molecular cages of ice. They are stable in the extreme cold and crushing weight of deepwater, but are extremely dangerous when they build up inside the drill column of a well. If destabilized by heat or a decrease in pressure, methane hydrates can quickly expand to 164 times their volume.

Survivors of the BP rig explosion that right before the April 20 blast, workers had decreased the pressure in the drill column and applied heat to set the cement seal around the wellhead. Then a quickly expanding bubble of methane gas shot up the drill column before exploding on the platform on the ocean's surface. 

Even a hardened steel pipe has little chance against a 164-fold expansion of volume โ€” something that would render a man six feet six inches tall suddenly the height of the Eiffel Tower.

Scientists are well aware of the awesome power of these strange hydrocarbons. A sudden large scale release of methane hydrates is believed to have caused a mass extinction 55 million years ago. Among planners concerned with mega-disasters, their sudden escape is considered to be a threat comparable to an asteroid strike or nuclear war. The Lawrence Livermore National Laboratory, a Livermore, Ca.-based weapons design center, that when released on a large scale, methane hydrates can even cause tsunamis.

So it is not surprising to anyone who knows about the physics of these compounds that the Deepwater Horizon rig was lost like a waterfly crumpled by a force of nature scientists are still just getting to know. 

Number One Deepwater Drilling Issue

SolveClimate contacted scientists at the who focus on the fundamental science and engineering of methane hydrates to gain further insight. They did not want to speculate on the role that methane hydrates could have played in the BP disaster, but they were willing to provide a basic understanding of the nature and behavior of these familiar but little understood substances.

"Gas hydrates are the number one flow assurance issue in deepwater drilling," Carolyn Koh, an associate professor and co-director of the Hydrate Center, told us in an exclusive interview.

She explained that the oil and gas industry has a lot of experience with methane hydrates, because they have to be kept from forming in pipes or they will clog the lines, stop the flow of oil, and pose a danger. Drillers use inhibitors such as methanol to keep the hydrates from crystallizing inside drill rigs operating at great depth, where conditions for methane hydrate formation are ideal.

This of an experiment conducted on the ocean floor near the Deepwater Horizon drilling site demonstrates how quickly and easily methane hydrates can form. It was conducted by the aboard the Seward Johnson in September 2006. The voices of the scientists conducting the experiment are clearly audible.

Poison Gases

Don't you think that our Gov should warn It's people of the dangers of the poison gases coming from the oil leak in the gulf?I have heard this from a reliable source. So they say.Send me a email and let me know. I live on the west coast of Fla.And is it true that the Well Head pressure at the time of the blast was between 20,000 to 100,000 psi ?And if they do manage to set off a atomic blast that it might crack the sea floor bed more and then they won't be able to do any thing to stop the leak? It makes you wonder when you are trying to sleep. Thank you so much and I will be looking for a response from you.To tell the truth.I am 82yrs old, Was hoping to make it to 100yrs Should I head North. Thanks again..

The methane hydrates are a

The methane hydrates are a known problem - that's why there was a special cement, special procedures, etc. The failure was 'caused' by a number of defects, shortcuts, bad decisions, etc. made about the process - it sounds like if about ten different stupid things weren't done, there simply wouldn't have been a blowout or fire.

When the blowout happened, they were celebrating the conversion of the well from an exploratory well to a production well - before it was finished, with workers taking shortcuts with cementing, working on incomplete information, with a known defective BOP.

So no, I don't think the methane had any more to do with it than the fact that the wellhead is underwater had to do with it - i.e. it wasn't a 'cause', it was just a part of the situation to be dealt with.

Dear Sir Telling Observation On Fixation

A telling observation, Dear Sir. Why fixate on the dangers of hydrate, indeed. Methane hydrate has its dangers, but it's major danger is where it is located physically, in a geopolitical sense, which is no more than an expression of the depth of the deposit which defines it as a realistic economic resource for the nation in whose waters it is located. (For example, there are those who wonder whether the US will sell offshore lease rights to Communist Chinese for methane hydrate exploitation as they have to BP and other non-national concerns.)

Dear Sir While I know it is

Dear Sir

While I know it is easy and tantalizing to conflate gas hydrate that forms in pipes and gas hydrate that forms naturally in sediment, they are very different things.

From published reports, the well blew out from a formation at a depth of more than 15,000 below the sea floor. Gas hydrates can not exist in sediments at depths any more than ~3,000 feet below the sea floor. It is simply too warm. This is simple thermodynamics, and I am sure if you ask this question to the folks you interview here at CSM and elsewhere, they will tell you the same.

There are plenty of reasons why this well blew out. Not sure why you fixate on this...

Dear Sir While I know it is

Re:Your saying cit. "From published reports, the well blew out from a formation at a depth of more than 15,000 below the sea floor. Gas hydrates can not exist in sediments at depths any more than ~3,000 feet below the sea floor. It is simply too warm."""
There are limitations to insitu hydrate stability of course; however; we can have hydrate pretty much right under the sea bottom. Destabilizing (release of heat or dropping pressure) such shallower hydrate (if there) could cause rapid gas release from hydrates and shootout of gas?

passive oil collector

now that the oil may be considered a raw force in the Gulf - heard of any style passive
collectors for the oil? Wouldn't have to stay close to the action for cleanup to happen.
Wouldn't have to direct others to stay close to the cleanup.
As it is we may only take a passive stance with the ecology doing the passive cleanup.
If there was simple buoy style passive collectors some more people could help by
finance and and construction and deployment and maintenance.
Regards.

Distinction

I think I made the distinction in the article sufficiently clear between hydrates in sediments and hydrates that form in pipes under the right conditions.

I don't know why you say I "fixate" on gas hydrates. It is certainly worth asking whether they played a role in the explosion.

It seemed like a reasonable to question to pursue after BP's cofferdam became clogged with gas hydrates almost as soon as it was lowered over the wellhead.

And I'm not the only one asking the question, by any means.

Certainly worth asking...

Absolutely, but if you think you are "asking", then maybe I am reading this wrong...

"So it is not surprising to anyone who knows about the physics of these compounds that the Deepwater Horizon rig was lost like a waterfly crumpled by a force of nature scientists are still just getting to know."

You think that is not asking? Really?

As to "fixate"... There are lots of good reasons why this well blew out. Did you not watch 60 minutes? A deep high pressure reservoir, the time pressures, the mud, the BOP, etc etc. The only mystery is why was the cement job bad? Of course, deep water reservoir cementing is a tough thing to do, prone to problems in good conditions, which is why the plugs are (usually) tested inside and out, and then (typically) confirmed with cement bond logs. So why all these words about a substance that isn't even capable of existing at anything near the depths at which this well blew out? Yes, hydrate has greatly complicated the post-blow out well intervention. But saying it caused the accident really makes very little sense other than the mysterious allure angle it can give a story, which is frankly not even on par with the "hydrates explain the Bermuda Triangle" stuff that one periodically sees, IMO...

By the way, the conditions in the cofferdam are WAY different from those in the borehole. About 10,000 psi and 150 degrees different.

I have some issues with your science as well, but I'll probably go over to the Guardian article to address that.

Thanks for listening.

Behind a Curtain

You seem to be awfully sure that methane hydrates had nothing to do with the blast.

Hmmm......

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