Gulf spill: is the methane a bigger problem than the oil?

Death from the depths

With the emerging evidence of fissures, the quiet fear now is the methane bubble rupturing the seabed and exploding into the Gulf waters. If the bubble escapes, every ship, drilling rig and structure within the region of the bubble will instantaneously sink. All the workers, engineers, Coast Guard personnel and marine biologists measuring the oil plumes' advance will instantly perish.

As horrible as that is, what would follow is an event so potentially horrific that it equals in its fury the Indonesian tsunami that killed more than 600,000, or the destruction of Pompeii by Mt. Vesuvius.

The ultimate Gulf disaster, however, would make even those historical horrors pale by comparison. If the huge methane bubble breaches the seabed, it will erupt with an explosive fury similar to that experienced during the eruption of Mt. Saint Helens in the Pacific Northwest. A gas gusher will surge upwards through miles of ancient sedimentary rock—layer after layer—past the oil reservoir. It will explode upwards propelled by 50 tons p/si, burst through the cracks and fissures of the compromised sea floor, and rupture miles of ocean bottom with one titanic explosion.

The burgeoning methane gas cloud will surface, killing everything it touches, and set off a supersonic tsunami with the wave traveling somewhere between 400 to 600 miles per hour. While the entire Gulf coastline is vulnerable, the state most exposed to the fury of a supersonic wave towering 150 to 200 feet or more is Florida. The Sunshine State only averages about 100 feet above sea level with much of the coastline and lowlands and swamps near zero elevation.
A supersonic tsunami would literally sweep away everything from Miami to the panhandle in a matter of minutes. Loss of human life would be virtually instantaneous and measured in the millions. Of course the states of Texas, Louisiana, Mississippi, Alabama and southern region of Georgia—a state with no Gulf coastline—would also experience tens of thousands, if not hundreds of thousands of casualties.

Loss of property is virtually incalculable and the days of the US position as the world's superpower would be literally gone in a flash...of detonating methane.

atheateroftheabsurd.blogspot.com...

I sincerely hope that this scenario does NOT play out, but I'm afraid that it will, albeit on a smaller scale than what is described here.

There is simply too much methane dissolved in the water for it not to happen on some scale.

People will die because of this, more than a few. It was inevitable from the beginning.

I have started to hear about this methane gas bubble.. I am not sure how to perceive it as of right now, yet concidering we are starting to get scientific, brainstorms from scientists right now, leading to a educated guess on what can happen if this leak is not contained very soon, is very very disheartening. I am also begining to think the US government or the presidential administration is aware of this danger, yet are not educating the public that is in danger. In addition I have also heard rumors that their is a gathering of UN equiptment in Jacksonvile FLA.


In addition this is just things I am hearing, from perhaps just the paranoid, yet not going to far left or right on this, I am trying to just get facts. Logic tells me if BP and the Government was aware of a Methane bubble burst possibility telling the public in danger the millions, would definately create a economic catastrophe.

Their are so many unanswered questions here, yet I am hearing more and more about this. In conclusion their are scientists in the gulf right now measuring the sea floor depth. Since the oil spill it has begun to drop...... Also one last note, it appears the platform hit a methane pocket in April, and that is why it exploded...

Just trying to stay in the middle.. Feel free to take this info far to the left or the right..

And now that the flow is unimpeded....

It's only going to get worse...

Until we fix it of course

Has anyone else noted that for the last couple of weeks at least one ROV has been either scanning the sea floor or observing apparently empty water but for the white squigglies zipping about?

The focus on the sea flor ROVs is crappy most of the time (which makes me suspect two video feeds from it, one in-focus private BP channel, out out-of-focus public one), but you can tell there is bubbling coming up out of the seafloor. Well, not exactly bubbling, but movement of sediment and water upwards. Some might argue that this is due to the ROV's wake, and they'd be right to a certain extant. But I've noticed the motion while the ROV wasn't moving, too.

The bit about the ROVs staring at empty water bugged me. It finally occurred to me that they might be dissolving methane hydrate bits and BP was trying to get a handle on how fast the hydrates on the seafloor around the wellhead were dissolving. Add that surmise to watching the seafloor, and it adds up to a lot more methane entering the water than is being publicly acknowledged.

Now, if enough dissolves in the water, bouyancy characteristics can be drastically altered to the point of not being able to float a ship . If a ship suddenly and inexplicably sinks, it should be interpreted as an example of the canary-in-the-coal-mine forewarning of impending huge shoreline disaster.

If such an event occurs, I advise people to withdraw from the coasts by at least ten or twenty miles for awhile.

[edit on 23-6-2010 by apacheman]

I don't have time to edit this down, but last might I recorded about a total of 4 hours while one of their ROVs was on patrol, looking for something .. methane I suppose. The following link is one of those recordings, the first one I captured, and it shows areas where it appears a white foggy gas is seeping up from the sediment on the gulf floor. You can play this with Windows Media Player and kick the speed up to 4x or faster and zip through it to more easily see these clouds of some kind of gas. Don't confuse the sediment kicked up by the ROV when it stops and backs up (you'll see that off on the sides and it will look different than the clouds of gas seeping up from the ground).

It's about 33 minutes long, and being on rapidshare, only the first 10 can download it. Maybe someone else has time to play with it, I'm just too busy today.

The Link to 33 minute ROV video (about 65mb)

It sure looks like BOA2 ROV is spraying dispersant into a leak off the seafloor.

There have been a couple of brief views that seem to show the seafloor leaking oil and gas from around the base of the BOP, but they shifted the views away from that very quickly.

Skandi ROV2 seems to be messing with an equipment package of some sort, the seafloor in that area seems to be leaking too, in addition to the kickup caused by the ROV.

Green stuff coming out of gulf oil!!! what is this?

link

www.youtube.com...

Thanks to Cloudsinthesky for this quote from this thread:
www.abovetopsecret.com...

Originally posted by Cloudsinthesky
"Texas A&M University oceanography professor John Kessler, just back from a 10-day research expedition near the BP Plc oil spill in the gulf, says methane gas levels in some areas are astonishingly high."

This is from Reuters www.reuters.com...

""There is an incredible amount of methane in there," Kessler told reporters in a telephone briefing."

"In some areas, the crew of 12 scientists found concentrations that were 100,000 times higher than normal."

If the alarm bells are not ringing now I am not sure when they will ring..........

There are two problems caused by the spill. Not only are these organisms being killed, but the breakdown of the oil by bacteria consumes oxygen. That will further increase the size of the dead zone — a low-oxygen area devoid of sea life that has existed for years — off Louisiana this summer.

Extraordinary quantities of methane are contributing to this problem. Underwater clouds of oil and methane gas have now been confirmed as originating from the BP blowout after weeks of denial. One of these clouds, encompassing an area the size of San Francisco and 600 feet thick, was found at 3,000 feet or more beneath the surface. Low levels of oil concentration (0.5 parts per million) have been found in this cloud. Researchers studying the clouds have found concentrations of methane up to 10,000 times greater than normal and oxygen levels depleted by 40 percent below normal.

This means organisms in the sea are suffocating and explains why microbes that require oxygen to break down the oil are not cleaning the spill naturally. Worse is that there are likely long-lived "dead zones" drifting through the Gulf and perhaps over deep-water ecosystems where recovery time can be centuries, or not at all. Other, larger clouds have been reported, and a large-scale and coordinated effort is searching for more.

Massive quantities of dispersants (1.28 million gallons by day 58 of the spill) are being used at both the wellhead (5,000 feet deep) and the surface of the ocean. Used effectively at the surface, dispersants can accelerate microbial activity and degradation of toxic elements of an oil spill. We have no idea about effectiveness or impact when used at such depth. It is, as has been stated, a giant experiment.

It is a difficult choice, and few would disagree that keeping oil out of the wetlands is a high priority. However, beneath the sea surface is a toxic soup of oil, methane and dispersants, which is also killing many sensitive parts of the ecosystem. Because this disaster is unfolding beneath the surface, it is occurring out of sight. Its effects are probably more devastating to the Gulf of Mexico and the sustainability of the Gulf economy than those we have already seen. These effects have been occurring since the beginning of the blowout, long before oil arrived on the shore.

www.statesman.com...

"More than a year ago, geologists expressed alarm in regard to BP and Transocean putting their exploratory rig directly over this massive underground reservoir of methane. Warnings were raised before the Deepwater Horizon catastrophe that the area of seabed chosen might be unstable and inherently dangerous.

Methane and Poison Gas Bubble: The US Environmental Protection Agency (EPA) has found high concentrations of gases in the Gulf of Mexico area. The escape of other poisonous gases associated with an underground methane bubble - such as hydrogen sulfide, benzene and methylene chloride - have also been found. Recently, the EPA measured hydrogen sulfide at more than 1,000 parts per billion (ppb) - well above the normal 5 to 10 ppb. Some benzene levels were measured near the Gulf of Mexico in the range of 3,000 to 4,000 ppb - up from the normal 0 to 4 ppb. Benzene gas is water soluble and is a carcinogen at levels of 1,000 ppb according to the EPA. Upon using a GPS and depth finder system, experts have discovered a large gas bubble, 15 to 20 miles wide and tens of feet high, under the ocean floor. These bubbles are common." - just-me-in-t.blogspot.com.../ •

The researchers are hoping to answer some basic questions about how much crude is flowing and where it is going. Although usually referred to as an "oil spill", the leak also contains large quantities of natural gas. "About half of the total flow is probably gas. The estimates out there now indicate that about 40% of the total mass flowing out is composed of methane.

"There's also a lot of ethane and propane and those three together make up a large fraction of natural gas," says Professor David Valentine from the University of California, Santa Barbara, one of the scientists on the RV Cape Hatteras.

Much of the methane in particular seems to be trapped in the water, rather than rising to the surface.

Atmospheric measurements just above the water do not show elevated readings of the gas, so the scientists believe it is held at depth, and spreading in what they are calling "plumes" - horizontal layers of gas and oil.

news.bbc.co.uk...


Now I'm sure the methane is worse than the oil. comparatively speaking, the oil is far easier to remove from the water, and isn't as potentially dangerous.

I'm not sure what all the churning a hurricane will do to these methane plumes, but I'll bet if you could list twenty effects, about fifteen would range from pretty bad to very nasty to catastrophic. I really don't want to find out, but I afraid that isn't an option.

Geologists are pointing to other fissures and cracks that are appearing on the ocean floor around the damaged wellhead.

According to CNN:

The University of South Florida recently discovered a second oil plume in the northeastern Gulf. The first plume was found by Mississippi universities in early May.

And there have been other plumes discovered by submersibles… Some geologists say that BP’s arrogance has set off a series of events that may be irreversible. There are some that think that BP has drilled into an deep-core oil volcano that cannot be stopped, regardless of the horizontal drills the company claims will stop the oil plume in August.

Need the mudlogs

Geologist, Chris Landau, for instance, has called for a showing of the mudlogs. A mudlog is a schematic cross sectional drawing of the lithology (rock type) of the well that has been bored.

So far, no one has seen them… BP keeps them hidden.

Mr. Landau claims:

It is a dangerous game drilling into high pressure oil and gas zones because you risk having a blowout if your mud weight is not heavy enough. If you weight up your mud with barium sulfate to a very high level, you risk BLOWING OUT THE FORMATION.

What does that mean? It means you crack the rock deep underground; as the mudweight is now denser than the rock, it escapes into the rock in the pore spaces and the fractures. The well empties of mud. If you have not hit high pressure oil or gas at this stage, you are lucky.

But if you have, the oil and gas come flying up the well and you have a blowout, because you have no mud in the well to suppress the oil and gas. You shut down the well with the blowout preventer. If you do not have a blowout preventer, you are in trouble as we have all seen and you can only hope that the oil and gas pressure will naturally fall off with time, otherwise you have to try and put a new blowout preventer in place with oil and gas coming out as you work.

Obviously, the oil and gas pressure hasn’t fallen off

In fact… it’s increased.

The problem is that BP may not only have hit the mother of high-pressure wells, but there is also a vast amount of methane down there that could come exploding out like an underwater volcano...

...The Oil Drum , an industry sheet, recently ran an article about the sequence of events that tried to stop the oil spill.

The upshot of industry insiders was that after trying a number of ways to close off the leak, the well was compromised, creating other leaks due to the high pressure. BP then cut the well open and tried to capture the oil.

In other words: BP shifted from stopping the gusher to opening it up and catching what oil it could.

The only reason sane oil men would do this is if they wanted to relieve pressure at the leak hidden down below the seabed… And that sort of leak — known as a “down hole” leak — is one of the most dangerous kind.

No stopping it

It means that BP can’t stop if from above; it can only relieve the pressure.

So, more oil is leaking out while BP hopes it can drill new wells before the current one completely erodes.

BP is in a race against time… It just won’t admit this fact.

www....[hate-site-nolink]/2010/06/28/vast-amount-of-methane-gas-near-underwater-oil-volcano/

The news doesn't seem to get better as time passes. There's more detail in the article, none reassuring, unfortynately.

Although I understand there is a real possibility of the methane bubble issue that claim of scientists detecting it with special tracking tech is just not substantiated - it sounds like it has been picked up from Richard Hoagland, whose claims can be found parroted in every single article about methane issues just about. The so called experts talking about the bubble are never mentioned ever ! Granted there is serious methane issue but no independent verification of the massive methane bubble. It's just bloggers and journalists picking up on Hoagland's claim from 2 weeks ago and Hoagland hasn't said a damn word about it since.

[edit on 28/6/10 by cosmicpixie]

reply to post by cosmicpixie


The methane bubble is genuine: dig back through this thread and you'll find the USGS reports on it, as well as industry reports.

In point of fact, it was the methane more than the oil that BP was interested in in the first place; going through the records and various press releases and the future role of natural gas, etc. make that obvious.

It is a very real danger, one that grows with every week, I think, at this point. Soon the danger level will be increasing on a daily basis until inevitably something occurs that reduces it.

One way would be to stop the leak, another to blow up or blow out the excess. Obviously the latter is NOT the way we want it to play out. That still leaves far more methane in the water than what is good for anything.

But that is just the "normal", mentally scaleable risk.

If there is a catastrophic failure of the seabed and the buble bursts rather than leaks, the scale of damage grows incomprehensibly large. One should look at the extremes to which a scenario may logically progress, assign a probablity, and mentally and physically prepare to deal with it.

When this thing began I set the percentage risk of seabed failure at less than 1 % in my own head. As it has progressed, that risk has been creeping up to where it now stands in my opinion: somewhere around 5%, far too high for comfort.

reply to post by apacheman

Thanks for that perspective. I wonder if they are monitoring sonar and seismic on the ocean floor around this disaster. It still sounds like they tapped into a veritable volcano of both oil and methane to me.

A couple of bits of good news (in my opinion any way).

1. Supposedly they are now going to try and cap the well with a bolt on top cap and recover 100% of the leaking oil and methane. They are currently flaring a lot of the Methane, so they have tempered that risk a little bit.

2. The relief wells seem to be going ahead of schedule, and I believe this will stop the leak, and also stop the seabed fractures. It is just my opinion, but I believe the drill pipe is ruptured in multiple places, and that is why the top kill did not work, and that is why the seabed is fracturing. If the relief wells pump in a sufficient amount of friction mud polymer and cement, then it should stop the leak all the way at the source and the ruptured pipe upline somewhere won't matter.

I don't think the caprock is fractured, I think it is just the drill tube that has ruptured and eroded away to the point that gas and oil are escaping before it ever reaches the BOP. If that is the case, then the relief well will still fix the whole issue. *cross fingers and prays*

The BP oil blowout, now into its 11th week, is releasing large quantities of methane into the ocean, most of which is remaining dissolved in the waters deep beneath the surface.

The gas represents an under-appreciated pollutant in a drill-rig disaster that has pumped as much as 60,000 barrels (2.5 million gallons) of oil a day into the Gulf of Mexico, researchers say.

Unlike the oil, the methane isn't coating birds or fouling beaches and wetlands. But it has the potential to wreak havoc on important links in the undersea food chain, researchers say.

By volume, some 40 percent of the hydrocarbons in the reservoir the Deepwater Horizon tapped is gas, of which 95 percent is methane, notes Samantha Joye, a marine scientist at the University of Georgia who has been gathering data at sea on the methane plumes.

By weight, she and her colleagues estimate, for every ton of oil spewing from the broken riser pipe, a half a ton of gas is blasting upward as well. "That's a tremendous amount of gas coming into the water column," she says.

Yet gas data represents the largest gap in efforts to take the full measure of the blowout, Dr. Joye says. That gap results from "the perception that it doesn't really matter; the focus is on oil, oil, oil."

Oil clearly has its own set of serious environmental effects. But the gas's behavior and fate at depth also is relevant to gauging the blowout's full ecological impact.

"It's not the same as the oil, but it's a big number," Joye says. "

We have to get a handle on it, and we don't have a handle on it right now."

...A 10-day research cruise in mid-June took measurements over a distance that ranged from about 1,600 feet from the blowout to eight miles away. The team, led by David Valentine from the University of California at Santa Barbara and John Kessler from Texas A&M University, found that methane concentrations "were low in the surface water and overlying air, very high at depths greater than 3,000 feet, and somewhat elevated in between," Dr. Valentine writes in an email exchange.

"We are interpreting this data to mean that the vast majority of the methane that escapes the top hat is trapped at depths of around one kilometer, and that only small amounts are likely to escape through the ocean to the atmosphere," he says.

The methane remains a captive of deep water because in temperate and tropical oceans, sea water forms stable layers that don't readily mix upward, he explains.

www.csmonitor.com...

Personally, Idon't think they've thought through the implications of the methane clouds yet. The oxygen is the limiting factor on microbial action, which would eliminate the threat if the methane wasn't constantly being replenished from the leak.

But:

a. the replenishment rate is far higher than the microbes can deal with.

b. they obviously haven't considered the consequences of the plumes being pushed into shallower waters.

c. nor have they considered what will happen when low pressure from a storm passes over the subsea cloud and lifts the water, which will change the pressure dynamics and allow the methane to rise.

I make these assertions based on what I'm not hearing them discuss. I can't blame them for not thinking of these things yet...this is all very new and they are focussed on a different level of the problem that is enormously complex and interesting from a science point of view.

So it's mostly a matter of being too busy and preoccupied to ask the right questions...

www.wtgexpert.com...

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 — 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 — 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.

Even a solid steel pipe has little chance against a 164-fold expansion of volume — 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, reports that when released on a large scale, methane hydrates can even cause tsunamis.

Expansion oh 164 times when melted is scary. Would if they have hit a large frozen methane pocket. They were 20 miles from a methane hydrate research site.

The Deepwater Horizon rig was drilling in Block 252 of an area known as the Mississippi Canyon of the Gulf, thought to contain methane hydrate-bearing sediments, according to government maps. The platform was operating less than 20 miles from a methane hydrate research site located in the same canyon at Block 118.

Here is Haliburtons PDF on "Deepwater Cementing Consideration to Prevent Hydrates Destabilization". So we know the deepwater cementing didn't go as planned so there is a good cjance of hydrates destabilization according to Haliburton.

www.aade.org...

A carbonate/hydrate mound in Mississippi Canyon Lease Block 118 (MC118) has been chosen by the Gulf of Mexico Hydrates Research Consortium to be the site of a sea-floor observatory.

This site MC118 is less then 20 miles from Deep Horizon drill site Mississippi Canyon block 252.

GAS COMPOSITION
Gas samples have been collected in the SW Complex from three vents and one intact piece of outcropping hydrate. Chemical analyses [1] show the vent gas to be thermogenic from deep hot source rocks and to average 95% methane, 3% ethane, 1% propane with minor other gases. There is no significant biogenic component. The outcropping hydrate is Structure II with gas composition 70% methane, 7.5% ethane, 15.9% propane with minor other gases. The difference between the gas compositions from the vents and the hydrate is due to molecular fractionation during hydrate crystallization (Sassen, pers. com.).

www.olemiss.edu...

Heres a video from 2006 from site MC118 which shows the methane bubbling up from the sea floor.

www.olemiss.edu...

Heres a picture from the Gulf of Mexico Hydrates Research Consortium looking toward Deep Horizon leak site.





Something to think about.



John Wathen video.

reply to post by JBA2848


Thanks for the added links, every scrap of information helps fill out the picture.

Anyone who's been paying attention knows I believe BP was far more interested in the methane deposits than the oil, and severely miscalcuted nearly every aspect of the drill plan.

Tow things stand out from the reports you cited.

First this on page 13 of the Halliburton report, especially the part I bolded:

Deepwater Well Objectives

• Cement slurry should be placed in the entire annulus with no losses
• Temperature increase during slurry hydration should not destabilize hydrates
• There should be no influx of shallow water or gas into the annulus
• The cement slurry should develop strength in the shortest time after placement

􀂾 Conditions in deepwater wells are not conducive to achieving all of these objectives simultaneously

The other thing that stands out is the ole miss report of vertical channels permeating the seabed with hydrate inclusions and free gas pockets scattered throughout.

If the casing is failing and is leaking sideways, those vertical channels will be widening inexorably, weakening the seabed around the wellbore. If it eats into a free gas pocket or hits a large chunk of hydrate, I can see larger pockets being pushed through the seabed closer to the seafloor until a big bubble pops out. How big?

That's the million dollar question.

www.olemiss.edu...

Multiple Outer Shelf Deltas and Downslope Massive Mass-Wastings ...

METHANE, MUD-LOGS AND THE CLATHRATE GUN

Congrats Apacheman....keep digging !

The basis of the clathrate gun is speculative but not unsubstantiated as others have suggested. The Russians and Chinese have further peer reviewed information.

The bubbling of methane from degassing of clathrate deposits is not to be confused with the concept of a methane bubble;

The degassing is a natural process but the recently reported volume in suspension is indicative of other problems related to the geology, the main evidence being the lack of evidence.... of the mud logs!. Current increases in methane in suspension are likely evidence that the gas is being driven out of the substrate at locations other than that depicted by the ROV. The process driving this is a combination of geothermal and/or seismological factors coupled with unconsolidated sediments in the Mississippi canyon area. The mud logs would help clarify this.

The methane bubble is yet to be verified but describes a gaseous rather than clathrate concentration heated by geothermal force but trapped by deep ocean pressure at the top of the geological structure that the oil is being pumped out of. The stability of this bubble is dependent upon a stable stratification of near ocean pressure, temperature and geology. Methane burps have been recorded and represent the release of the methane as a gas in a convection process or water column eruption. These large releases are not dissolved, and are speculated as a cause of reducing buoyancy in the release area. At the ocean surface the gas is toxic and explosive but quickly dissipates. A small release of this type is the 'kick' which likely killed the boys on the drilling platform.

The clathrate gun scenario is well explored in fiction; the mechanisms offered for this include large scale tectonic/volcanic activity and landslips which may or may not be related to that activity. The mechanism involved is essentially creating a massive disturbance of the stable stratified ocean in the vicinity of the methane deposit. This has the potential to create a runaway chain reaction based on convection where a significant methane deposit may exploit and maintain the convection cell until the geological pressure driving the deposit is dissipated.

Considering the volumes of clathrate estimated for this part of the gulf and the pressures speculated by industry within the formation, the chances are not infinitesimal assuming an appropriate trigger were provided. A nuclear device of the appropriate size in the right location may well fulfill this requirement.

Anyway, back offshore.. to the far western pacific!

METHANE, MUD-LOGS AND THE CLATHRATE GUN

Congrats Apacheman....keep digging !

The basis of the clathrate gun is speculative but not unsubstantiated as others have suggested. The Russians and Chinese have further peer reviewed information.

The bubbling of methane from degassing of clathrate deposits is not to be confused with the concept of a methane bubble;

The degassing is a natural process but the recently reported volume in suspension is indicative of other problems related to the geology, the main evidence being the lack of evidence.... of the mud logs!. Current increases in methane in suspension are likely evidence that the gas is being driven out of the substrate at locations other than that depicted by the ROV. The process driving this is a combination of geothermal and/or seismological factors coupled with unconsolidated sediments in the Mississippi canyon area. The mud logs would help clarify this.

The methane bubble is yet to be verified but describes a gaseous rather than clathrate concentration heated by geothermal force but trapped by deep ocean pressure at the top of the geological structure that the oil is being pumped out of. The stability of this bubble is dependent upon a stable stratification of near ocean pressure, temperature and geology. Methane burps have been recorded and represent the release of the methane as a gas in a convection process or water column eruption. These large releases are not dissolved, and are speculated as a cause of reducing buoyancy in the release area. At the ocean surface the gas is toxic and explosive but quickly dissipates. A small release of this type is the 'kick' which likely killed the boys on the drilling platform.

The clathrate gun scenario is well explored in fiction; the mechanisms offered for this include large scale tectonic/volcanic activity and landslips which may or may not be related to that activity. The mechanism involved is essentially creating a massive disturbance of the stable stratified ocean in the vicinity of the methane deposit. This has the potential to create a runaway chain reaction based on convection where a significant methane deposit may exploit and maintain the convection cell until the geological pressure driving the deposit is dissipated.

Considering the volumes of clathrate estimated for this part of the gulf and the pressures speculated by industry within the formation, the chances are not infinitesimal assuming an appropriate trigger were provided. A nuclear device of the appropriate size in the right location may well fulfill this requirement.

Anyway, back offshore.. to the far western pacific!