Substantial quantities of extractable methane hydrates identified in Alaska

Methane hydrates (aka frozen gas, frozen methane, gas clathrates, gas hydrates, clathrate hydrates) are water ice that contain a large amount of methane (aka natural gas) within their crystalline structure [see http://en.wikipedia.org/wiki/Clathrate_hydrate]. Paleogeologists point to the melting of methane hydrates as one reason why the "snow-ball Earth" (when the Earth was covered almost completely with thick sheets of ice [see http://en.wikipedia.org/wiki/Snowball_Earth]) was able to unfreeze approximately 600+ million years ago. Climatologists today are concerned that the melting of the Earth’s methane hydrates will help drive global warming to a significant temperature increase [see http://en.wikipedia.org/wiki/Clathrate_Gun_Hypothesis]. [As noted in a prior post: "This means that a methane emission will have 25 times the impact on temperature of a carbon dioxide emission of the same mass over the following 100-year period. Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20-year time period is a whopping 72. See http://en.wikipedia.org/wiki/Methane."] Methane, or natural gas, is desirable because it is more environmentally benign than other hydrocarbons. [See http://www.naturalgas.org/overview/background.asp.] It has generally been assumed that methane hydrates would be difficult to access, and that only if hydrocarbon prices remained high would it be economic to recover methane from these formations. The U.S. Geological Service has identified formations that may be more economic to exploit. The area assessed in northern Alaska extends from the National Petroleum Reserve in Alaska (NPRA) on the west through the Arctic National Wildlife Refuge (ANWR) on the east and from the Brooks Range northward to the State-Federal offshore boundary (located three miles north of the coastline). This area consists mostly of Federal, State, and Native lands covering about 55,894 sq. miles. Needless to say, environmentalists are opposed to any intrusion into ANWR. For the Northern Alaska Gas Hydrate Total Petroleum System, the USGS estimates that the total undiscovered natural gas resources in gas hydrate range between 25.2 and 157.8 trillion cubic, with a mean estimate of 85.4 TCF [the U.S. uses approximately 23 TCF of natural gas annually; see http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/11/13/MN9L1438D8.DTL&hw=methane+hydrate&sn=001&sc=1000]. Of this mean estimate, (1) about 24 percent (20.6 TCF) is in the Sagavanirktok Formation Gas Hydrate assessment unit (AU), (2) 33 percent (28.0 TCF) is within the Tuluvak-Schrader Bluff-Prince Creek Formations Gas Hydrate AU, and (3) 43 percent (36.9 TCF) is in the Nanushuk Formation Gas Hydrate AU (table 1). Given that relatively few wells have penetrated the expected gas hydrate accumulations in these three AUs, there is significant geologic uncertainty in these estimates. The mean estimate of 85.4 TCF of gas within the gas hydrates of northern Alaska is considerably less than the 590 TCF reported in the 1995 USGS assessment. It is critical to note that the 1995 assessment only dealt with estimating the in-place volume of gas with hydrates, whereas this more recent assessment dealt only with technically recoverable gas. Also, the 1995 assessment included the offshore Federal waters, which were not included in this assessment. The USGS believes this methane resource can be recovered with today’s technology. Fundamentally, water is injection to melt the ice, and the process water and methane are extracted; the process water will need to be treated. The extraction process is deemed to be more environmentally benign than coat-bed methane extraction, which also uses substantial water. Given the very substantial effect of methane on global warming, as noted above, any extraction process will need to be very cautious about allowing methane to escape into the atmosphere. The U.S.G.S. Fact Sheet, Press Release, and Slide Presentation can be found at http://energy.usgs.gov/other/gashydrates/alaska.html. Information on methane hydrate formations worldwide can be found at http://energy.usgs.gov/other/gashydrates/.