USGS estimates nearly 39 billion barrels of oil undiscovered and technically recoverable in two Arctic petroleum provinces; 275 trillion feet of gas
28 November 2012
|Map of Arctic Alaska Province (outlined in black) showing boundaries of the platform and fold-and-thrust belt assessment units in red. Source: USGS. Click to enlarge.|
The US Arctic Alaska Petroleum Province holds mean estimates of undiscovered, technically recoverable oil and gas resources of nearly 30 billion barrels of oil, about 179 trillion cubic feet of nonassociated gas, and 40 trillion cubic feet of associated gas, according to a new assessment published by the US Geological Survey (USGS).
The larger Amerasia Basin Petroleum Province, which extends north and east of the Arctic Alaska Province, holds an estimated risked, undiscovered, technically recoverable 9 billion barrels of oil, 29 trillion cubic feet of associated gas, and 27 trillion feet of nonassociated gas, according to another new assessment from the USGS.
Arctic Alaska Province. The Arctic Alaska Petroleum Province encompasses all lands and adjacent continental shelf areas (i.e., offshore) north of the Brooks Range-Herald arch tectonic belts and south of the northern (outboard) margin of the Alaska rift shoulder. Even though only a small part is thoroughly explored, it is one of the most prolific petroleum provinces in North America, with total known resources (cumulative production plus proved reserves) of about 28 billion barrels of oil equivalent, according to USGS.
For assessment purposes, the province is divided into a platform assessment unit (AU), comprising the Alaska rift shoulder and its relatively undeformed flanks, and a fold-and-thrust belt AU, comprising the deformed area north of the Brooks Range and Herald arch tectonic belts.
The Arctic Alaska platform AU includes at least 15 oil and 2 gas accumulations larger than 50 MMBOE, including the largest oil field in North America at Prudhoe Bay. [Estimated original oil in place 25 billion barrels, more than 13 billion recoverable.] Considering that a relatively small proportion of the AU has been explored, the potential for discovery of additional accumulations is considered high. Mean estimates for undiscovered, technically recoverable resources in conventional accumulations include nearly 28 BBO, more than 37 TCF of associated gas, and more than 120 TCF of nonassociated gas.
The Arctic Alaska fold-and-thrust belt AU is lightly explored and includes multiple oil and gas discoveries, including at least one oil and one gas accumulation that exceed the 50-MMBOE threshold for the CARA. Exploration in this AU has been limited by the absence of a market for natural gas and the perception that it is a gas-prone region. The potential for discovery of additional accumulations is considered high. Mean estimates for undiscovered, technically recoverable resources in conventional accumulations include 2 BBO, nearly 3 TCF of associated gas, and 59 TCF of nonassociated gas.—Houseknecht et al., 2012a
|Amerasia Basin Petroleum Province. Source: USGS. Click to enlarge.|
Amerasia Basin Petroleum Province. The Amerasia Basin Petroleum Province encompasses the Canada Basin and the sediment prisms along the Alaska and Canada margins, outboard from basinward margins (hingelines) of the rift shoulders that formed during extensional opening of the Canada Basin. The province includes the Mackenzie delta and slope, the outer shelves and marine slopes along the Arctic margins of Alaska and Canada, and the deep Canada Basin.
The province is divided into four assessment units (AUs):
The Canning-Mackenzie deformed margin AU is that part of the rifted margin where the Brooks Range orogenic belt has overridden the rift shoulder and is deforming the rifted-margin prism of sediment outboard of the hingeline. This is the only part of the Amerasia Basin Province that has been explored and—even though more than 3 billion barrels of oil equivalent (BBOE) of oil, gas, and condensate have been discovered—none has been commercially produced.
The Alaska passive margin AU is the rifted-margin prism of sediment lying beneath the Beaufort outer shelf and slope that has not been deformed by tectonism.
The Canada passive margin AU is the rifted-margin prism of sediment lying beneath the Arctic outer shelf and slope (also known as the polar margin) of Canada that has not been deformed by tectonism.
The Canada Basin AU includes the sediment wedge that lies beneath the deep Canada Basin, north of the marine slope developed along the Alaska and Canada margins.
Mean estimates of risked, undiscovered, technically recoverable resources include:
More than 6 billion barrels of oil (BBO), more than 19 trillion cubic feet (TCF) of associated gas, and more than 16 TCF of nonassociated gas in the Canning-Mackenzie deformed margin AU;
About 1 BBO, about 3 TCF of associated gas, and about 3 TCF of nonassociated gas in the Alaska passive margin AU; and
more than 2 BBO, about 7 TCF of associated gas, and about 8 TCF of nonassociated gas in the Canada passive margin AU.
The Canada Basin AU was not quantitatively assessed because it is judged to hold less than 10 percent probability of containing at least one accumulation of 50 million barrels of oil equivalent.
Houseknecht, D.W., Bird, K.J., and Garrity, C.P., (2012a) Assessment of undiscovered petroleum resources of the Arctic Alaska Petroleum Province: US Geological Survey Scientific Investigations Report 2012–5147 26 p., available only at http://pubs.usgs.gov/sir/2012/5147
Houseknecht, D.W., Bird, K.J., and Garrity, C.P. (2012b) Assessment of Undiscovered Petroleum Resources of the Amerasia Basin Petroleum Province: US Geological Survey Scientific Investigations Report 2012–5146 26 p., available only at http://pubs.er.usgs.gov/publication/sir20125146
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