USGS releases first shale-oil and shale-gas resource potential assessment for the Alaska North Slope
The US Geological Survey has released its first estimate of the potential of undiscovered, technically recoverable onshore shale oil and gas resources in Alaska’s North Slope. The estimates range from 0 up to 2 billion barrels of oil and from 0 up to 80 trillion cubic feet of gas—representing technically recoverable oil and gas resources, which are those quantities of oil and gas producible using currently available technology and industry practices, regardless of economic or accessibility considerations.
Primarily due to economic and infrastructure considerations, production has never been attempted from these Alaska North Slope shales, which span most of the North Slope but are largely absent from the environmentally sensitive Arctic National Wildlife Refuge.
Providing scientifically sound, publicly available assessments of the quantity of new, untapped oil and gas resources in frontier areas is but the first step in weighing their potential contributions to energy supplies as well as the impacts of recovering them. This information can help leaders from both government and industry make good decisions for the long term, anticipate environmental issues in advance of development, and guide wise investments.—USGS Director Marcia McNutt
There is a large range of uncertainty associated with these assessment numbers, because of the uncertainty associated with estimation of undiscovered, continuous resources in source rocks from which no attempt has been made to produce oil or gas. However, the recent success of shale oil and shale gas development in the lower-48 states demonstrates the technical viability of such resources, USGS said. Therefore, this new USGS assessment provides an estimate of potential resources that may be technically viable in this frontier region.
Three source rocks of the Alaska North Slope were assessed in this study: the Triassic Shublik Formation, the lower part of the Jurassic-Lower Cretaceous Kingak Shale, and the Cretaceous pebble shale unit-Hue Shale.
These shale formations are known to have generated oil and gas that migrated into conventional accumulations, including the super-giant Prudhoe Bay field. However, these shales also likely retain oil and gas that did not migrate.
Shales like those found in North Slope Alaska are known as source rocks—those formations from which hydrocarbons, such as oil and gas, originate. Conventional oil and gas resources gradually migrate away from the source rock into other formations, whereas continuous resources, such as shale oil and shale gas, remain trapped within the original source rock.
Shale oil is oil that was generated naturally in source rocks but that never migrated out of them. It should not be confused with “oil shale,” a source rock in which oil has not yet been generated, but that is capable of generating oil if artificially heated.
USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas resources of onshore lands and offshore state waters. The USGS worked with the Alaska Department of Natural Resources, the University of Alaska-Fairbanks, and others knowledgeable about North Slope geology for input into the geological models of the petroleum source rocks. This USGS assessment was undertaken as part of a nationwide project assessing domestic petroleum basins using standardized methodology and protocol.
Houseknecht, D.W., Rouse, W.A., Garrity, C.P., Whidden, K. J. , Dumoulin, J.A., Schenk, C.J., Charpentier, R.R., Cook, T.A., Gaswirth, S.B., Kirschbaum, M.A., and Pollastro, R.M., 2012, Assessment of potential oil and gas resources in source rocks of the Alaska North Slope, 2012: U.S. Geological Survey Fact Sheet 2012–3013, 2 p.