Newly discovered methane hydrate reserves deep in the ocean show promise for mining

[bik0]

Trapped in molecular cages resembling ice, at the bottom of the ocean and in terrestrial permafrost all over the world, is a supply of natural gas that, by conservative estimates, is equivalent to twice the amount of energy contained in all other fossil fuels remaining in the earth's crust. The question has been whether or not this enormous reserve of energy, known as methane hydrates, existed in nature in a form that was worth pursuing, and whether or not the technology existed to harvest it.

Last Friday, the United States Geological Survey (USGS) announced the discovery of suitable conditions for mining methane hydrates 1,000 meters beneath the seabed in the Gulf of Mexico. Together with Chevron and the U.S. Department of Energy, the USGS discovered the reserve of hydrates in high concentrations in 15-to-30-meter-thick beds of sand--conditions very much like terrestrial methane hydrate reserves, which have already yielded commercially useful flow rates. These deposits are substantially different from the gas hydrates that have previously been discovered in U.S. coastal waters, which exist in relatively shallow waters at the surface of the seabed and have become a concern for climate scientists because of their potential to melt rapidly and release large quantities of methane into the atmosphere.

While no one believes that all of the world's methane hydrates will be recoverable, the scale of global reserves has been described by the U.S. Department of Energy as "staggering." They occur anywhere that water, methane, low temperatures, and high pressure co-occur--in other words, in the 23 percent of the world's land area covered by permafrost and at the bottom of the ocean, particularly the continental shelf.

http://goo.gl/rLZ8

[itsrobert]

1. Waiting for the conspiracy theorist to say

that the US while reseaching this find in the Gulf of Mexico triggered the Earthquake in Haiti. In 5...4....3....2...

[Richard D]

2. and if the ocean temperatures rise too much . . .

. . . the methane will be released into the atmosphere as an astoundingly powerful greenhouse gas.

[Statistical]

4. The only "good" news is that the world will be destroyed by then.

At 1000m the melting point is 18deg C.
Currently the ocean temp at 1000m is about 4deg C.

The 14deg increase in ocean temp needed to melt the methane likely would destroy the world as we know it.

[bik0]

5. Do you have a time frame?

A 14deg temperature rise at 1000m requires a much higher temp rise near the surface does it not? How soon will it happen in your opinion?

[Statistical]

7. A 14degree rise @ 1000m likely is +40-50 degrees on the surface.

I don't know how long it will take to happen I was just indicating the release of methane will be the least of our worries. Likely will be the end of life on earth anyways. :)

[NickB79]

8. Unless ocean currents shift due to climate change

And a nice warm Gulf stream of water is re-directed into a region with large quantities of methane hydrates. No need to have an even, global heating then.

[kristopher]

9. They missed this part of the OP

"These deposits are substantially different from the gas hydrates that have previously been discovered in U.S. coastal waters, which exist in relatively shallow waters at the surface of the seabed and have become a concern for climate scientists because of their potential to melt rapidly and release large quantities of methane into the atmosphere."


What is the temp at to release methane hydrates at 60m?

[Statistical]

11. well that is a bigger problem.

Methane hydrate melts at around 18deg Celcius at normal at 1 atmosphere of pressure. At 60m it is more like 7 atmospheres of pressure. This should lower melting point "somewhat". Without a chart showing melting point of methane hydrates at various pressures it is hard to say for sure.

Shallow methane hydrate melting could be a problem much sooner. Shallow water (above thermocline) is affected by climate and changing currents which could accelerate localized melting.

[Statistical]

10. Anything is possible however...

The thermocline is only about 100m to 200m deep.

Currents, sunlight, and streams constantly mix and change temperature of surface water (<100 - 200m deep) however there is very little transference of heat past the thermocline.

Water deeper than 200m tends to be very stable in terms of temperature. Water below the thermocline doesn't have much (if any) seasonal variation or even day/night variation.

The sheer amount of water and the isolating aspect of the thermocline makes it rather uniformly cold regardless of local temperature variations, seasons, or climate.

[petronius]

20. The article says 1000m beneath the sea bed, not the sea surface

So even a massive ocean warming wouldn't affect these deposits...

[Statistical]

21. That was kinda my point.

In order for the 100m deep ocean (below thermocline) to rise the 14+ deg necessary to melt the deposits it would require an utterly massive rise in atmospheric temperatures. Something like 40-50 deg rise over centuries.

The ocean is a quite massive heat sink.

So no need to worry about them melting because any climate change with enough energy to melt these deposits likely has wiped most life off the planet already.

Then again after stating that I learned some deposits are found in shallow waters and in artic permafrost. So that could be bad.

[kristopher]

22. If only a few percent of the deposits in shallow waters are released - mass extinction results.

[Statistical]

23. Oops I missed the seabed vs sea level distinction.

I think the article is wrong.

It contradicts itself says in 30m sand and then later says 100m below seabed.
Methane Hydrates occur in shallow sand on continental shelf. 1000m below surface of earth (and seabed) the the temperature is substantially higher that hydrates don't form.

Likely is just careless writing by the author.

[petronius]

24. I'm not so sure - the USGS fact sheet says that clathrates can exist in

sediment down to 1000m below the sea bed (limited by increasing temperature) and the article does make the distinction between this find and those deposits found on/near the sea bed. I think the writer got it right - these deposits are in deeply buried layers of sand (which are themselves ~30m thick), which is unusual compared to the typical shallow locations. It would be interesting to know if the deposits formed at their current location, or if they formed more shallowly and were subsequently buried...

[NNadir]

14. That wouldn't be dimethyltryptamine, would it, in your avatar?

It has no color and therefore I can't tell if any of those are nitrogens.

Certainly the connectivity matrix is the same.

If so, you're in the right place. Many of the posts here are the E&E forum read like hallucinations, including maybe, the OP.

[joshcryer]

15. I think the name of the file is a clue.

[Richard D]

17. ;-)

yup.

[NNadir]

18. It was an interesting molecule in the history of medicinal chemistry.

I remember a paper I read many, many, many years ago about isotopic effects involving that compound and its neurological action, deutero DMT vs protonic DMT.

It stuck in my mind. I am always interested in the pharmacokinetics of isotopes of various kinds.

[pscot]

19. What luck

We won't have to mine it or burn it, thus eliminating the middle man.

[GeorgeGist]

3. ummmmmm

sounds yummy.

[elocs]

6. As a greenhouse gas methane is 23 times more potent that CO2.

Runaway global warming...101:

http://www.indypendent.org/2007/06/07/runaway-global-warming-101/

Methane Hydrate Release
The gradual warming of sea sediments and increase runoff from rivers could lead to underwater landslides along the ocean’s continental margins. This could release billions of tons of frozen methane hydrates stored beneath the ocean floor. This last occurred 55 million years ago. In an event known as the Paleocene-Eocene Thermal Maximum, global temperatures rose by an additional 9-13 degrees Fahrenheit. The potential effects of such a release read like a bad Hollywood script: giant exploding fireballs ripping across the sky, the shredding of the ozone layer, oceanic life driven to extinction for lack of oxygen, and the appearance of continent-sized “hypercanes” with winds as high as 500 mph.

Coming to a planet near you: this one actually.

[Richard D]

12. There was a SF book written about his . . .

. . . can't recall the title right now, but the idea was that a large meteor hit a MH deposit in the ocean releasing megatons of the stuff. Quite an alarming read.

[bhikkhu]

13. Methane hydrate is a fossil fuel, a CO2 producer when burned.

I think climate change should have us a little smarter by now, so a new "we just found another brazillion tons of stuff to burn!" announcement isn't exactly a cause for joy or relief...

[Nihil]

16. It's sad isn't it?

> a new "we just found another brazillion tons of stuff to burn!" announcement
> isn't exactly a cause for joy or relief...

Especially when you consider the "natural leakage" when they would be
extracting this new fuel source would greatly accelerate the effect of
simply burning the methane.

Talk about "idiocracy" ...