Assessment Data For Oil And Gas Potential Of Alaska Federal Offshore


This report and its attached files provide an interim posting of the data and results of the Minerals Management Service assessment of the quantities of undiscovered oil and gas associated with geologic plays that lie beneath submerged Federal lands offshore of Alaska. Resource estimates include both undiscovered geologic oil and gas, consisting of conventionally recoverable resources unconstrained by economics, as well as the more modest quantities of undiscovered economic oil and gas that might, once discovered, be recovered at a profit.

This assessment of the Alaska Federal offshore was conducted as part of a national appraisal of all lands in the United States performed jointly by the bureau and the U.S. Geological Survey (USGS). The USGS assessed all onshore lands and submerged lands in State waters (USGS, 1995). The bureau simultaneously assessed the undiscovered oil and gas potential of submerged lands in Federal waters. Bureau assessments of the Federal offshore are conducted periodically (Cooke, 1985, 1991; Cooke and Dellagiarino, 1989) and the results are used to guide management of leasing and exploration policies and programs in the Federal offshore.

In Alaska, Federal waters generally begin 3 miles from shore and extend up to 200 miles seaward. For the purposes of this assessment, the Alaska offshore was divided into 17 geologic provinces. Eleven of these provinces, all on the continental shelves, offer potential for conventional supplies of oil and gas. Within these 11 assessment provinces, oil and gas endowments were calculated for 74 exploration plays. The attached files list the geologic data provided to mathematic models and used to calculate oil and gas endowments of each of the 74 plays ("Tables for Play Input Data"). Other attached files report the results of those calculations, both geologic and economic resources, for all 74 plays.

The quantities of oil and gas were calculated using two computer models (GRASP and PRESTO) that statistically analyze input data provided as ranges of values reflecting different probabilities for occurrence. These data are drawn from a vast offshore database of geophysically mapped prospects, data from offshore wells, and development cost data gathered over years of offshore work in Alaska.

The Alaska offshore is estimated to offer an average (mean) potential for undiscovered, conventionally recoverable oil of 24 billion barrels, with a 5-percent chance of oil resources exceeding 34 billion barrels. Gas potential averages 126 trillion cubic feet, with a 5-percent chance of gas resources exceeding 230 trillion cubic feet.

Approximately 90 percent of the undiscovered conventionally recoverable oil endowment in offshore Alaska occurs within the Chukchi shelf (13 billion barrels) and Beaufort shelf (9 billion barrels) provinces, which lie adjacent to the rich Arctic Alaska (onshore) oil province. The Arctic Alaska (onshore) province is endowed with original oil reserves of 16.4 billion barrels and a discovered total of 70 billion barrels of oil in place. The Arctic Alaska (onshore) province produces about 1.5 million barrels per day and accounts for nearly 25 percent of all current U.S. daily oil production.

Most of the oil and gas resources of the Alaska offshore occur in accumulations too small to warrant commercial exploitation within the forseeable future. Only about 15 percent of the geologic oil endowment of offshore Alaska occurs in accumulations sufficiently large to be "economic", or, that could be profitably developed at prices approaching those that exist today. "Economic" resource quantities reported here are from price-supply curves (given in each province under "Economic Results") at commodity prices of $18 per barrel of oil and $2.11 per thousand cubic feet of gas.

On average, the Alaska Federal offshore is estimated to offer 3.75 billion barrels of undiscovered, economically recoverable oil, with a 5-percent chance of exceeding 7.65 billion barrels. Most of the undiscovered, economically recoverable oil resources occur beneath the Beaufort shelf (2.27 billion barrels of oil) and Chukchi shelf (1.14 billion barrels of oil). The rest of the undiscovered, economically recoverable oil resources of the Alaska Federal offshore occur in Cook Inlet (0.27 billion barrels of oil).

Most of the conventionally recoverable gas resources occur beneath the Beaufort and Chukchi shelves, but these resources are considered uneconomic because of the lack of an infrastructure for gas transport.

A report summarizing the results of the assessment of the Alaska offshore is posted as "Oil and Gas Potential of Alaska Federal Offshore, (1995 National Assessment)". Printed copies of the executive summary, designated MMS 96-0033, may be obtained free of cost by contacting:

  Mail: Public Information
Bureau of Ocean Energy Management, Regulation and Enforcement
Alaska OCS Region
3801 Centerpoint Drive, Suite 500
Anchorage, AK 99503
  Phone: 1-800-764-2627

Comments about these reports or requests for more information may also be provided through any of the the contact points given above.

The assessment of the Alaska Federal offshore will be documented in a comprehensive printed report scheduled for publication in 1997. The comprehensive report will tabulate all data used in geologic modeling and it will fully document geologic rationales used in the preparation of play data. The comprehensive report will also report and analyze the quantitative results of the geologic and economic modeling.

References Cited

Cooke, L.W., 1985, Estimates of Undiscovered, Economically Recoverable Oil and Gas Resources for the Outer Continental Shelf as of July 1984: Minerals Management Service, OCS Report, MMS 85-0012, 45 p.

Cooke, L.W., 1991, Estimates of Undiscovered, Economically Recoverable Oil and Gas Resources for the Outer Continental Shelf, Revised as of January 1990: Minerals Management Service, OCS Report, MMS 91-0051, 30 p.

Cooke, L.W., and Dellagiarino, G., 1989, Estimates of Undiscovered Oil & Gas Resources for the Outer Continental Shelf as of January 1987: Minerals Management Service, OCS Report, MMS 89-0090, 114 p.

USGS (U.S. Geological Survey), 1995, 1995 National Assessment of United States Oil and Gas Resources: U.S. Geological Survey, Circular 1118, 20 p., with CD-ROM.