WASHINGTON, D.C. (Nov 12, 2008) – Secretary of the Interior Dirk Kempthorne and U.S. Geological Survey Director Mark Myers today released a USGS assessment estimating that there are 85.4 trillion cubic feet of undiscovered, technically recoverable gas from natural gas hydrates on the Alaskan North Slope. This would be enough natural gas to heat more than 100 million average homes for 10 years, according to current usage rates provided by the Energy Information Administration. However, further research, including long-term production tests, still is needed to demonstrate gas hydrates as an economically producible resource.
“The assessment points to a truly significant potential for natural gas hydrates to contribute to the energy mix of the United States and the world,” Secretary Kempthorne said at a press conference at the Interior Department headquarters in Washington. “This study also brings us closer to realizing the potential of this clean-burning natural gas resource.”
The USGS assessment is the first-ever resource estimate of technically recoverable natural gas hydrates, which are naturally occurring, ice-like solids in which water molecules trap natural gas molecules in a cage-like structure known as a clathrate.
The USGS estimates that the 85.4 TCF of gas accounts for 11.5 percent of the volume of gas within all other undiscovered, technically recoverable gas resources onshore and in the state waters of the United States. “Technically recoverable” means the resource can be discovered, developed, and produced using current technology and industry practices.
The world currently consumes about 104 TCF of natural gas a year and the United States uses about 23 TCF of natural gas per year, according to the Energy Information Administration. Other USGS assessments of undiscovered, technically recoverable natural gas resources (NOT GAS HYDRATES) estimate that the Wyoming Basin holds 85 TCF, National Petroleum Reserve in Alaska holds 73 TCF, Western Gulf Basin in Texas holds 71 TCF, and the San Juan Basin in New Mexico and Colorado holds 50 TCF. Conventional undiscovered, technically recoverable gas resources on the North Slope of Alaska are estimated at 119.15 TCF.
“For more than 25 years, the USGS has conducted gas hydrate research in northern Alaska, showing the investment of our agency in understanding this resource,” said USGS Director Mark Myers. “This is especially important now that a growing body of evidence indicates that concentrated gas hydrate accumulations in conventional hydrocarbon reservoirs, such as those in northern Alaska, can be produced with existing technology.”
Among the various techniques for production of natural gas from gas hydrates, depressurization appears to be the most promising method. This involves changing the pressure of the hydrate accumulation, which changes the resource from a solid state into components of gas and water that can be produced to the surface. Depressurization was the only production technique assessed in this estimate.
The area assessed in northern Alaska extends from the National Petroleum Reserve in Alaska on the west through the Arctic National Wildlife Refuge on the east and from the Brooks Range northward to the state-federal offshore boundary (located three miles north of the coastline).
Of the estimated 85.4 TCF of gas within hydrates on the North Slope, 56 percent occurs on federally managed lands, 39 percent on lands and offshore waters managed by the State of Alaska, and 4 percent on Native Alaskan lands. The assessment of the potential gas hydrate resources on the federally managed offshore regions of northern Alaska is being conducted by the Minerals Management Service.
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 of domestic natural gas hydrates. This difference is because the 1995 assessment included all volumes of gas, whereas this assessment deals only with technically recoverable gas. Also, the 1995 assessment included offshore federal waters of Alaska, which were not included in this assessment. The approach used to assess the gas hydrate resources in northern Alaska followed current standard geology-based USGS assessment methodologies developed to assess conventional oil and gas resources.
The research project in support of this assessment was a cooperative effort with the Bureau of Land Management, who provided the geologic and geophysical datasets of the Alaskan North Slope. Both USGS and BLM are agencies of the Department of the Interior.
To learn more about USGS research on natural gas hydrates and to see results of the gas hydrate assessment in northern Alaska, please visit http://energy.usgs.gov/. To listen to a podcast interview about the USGS assessment of undiscovered, technically recoverable gas from natural gas hydrates on Alaska's North Slope, visit USGS CoreCast at http://www.usgs.gov/corecast.
To learn more about research in the Bureau of Land Management’s Alaska office, please visit http://www.blm.gov/ak/st/en.html.