U. S. Shale Gas Resources: Classic and Emerging Plays, the Resource Pyramid and a Perspective from Future E&P

John B. Curtis¹ and David G. Hill^2
1Geology & Geological Eng., Colorado School of Mines, Golden, CO
²EnCana Oil and Gas (USA), Inc., Denver, CO

Projections by the United States government indicate that annual U.S. gas demand could increase from the current 22 Tcf (trillion cubic feet) to 26 Tcf by the year 2030. This would occur during a period of declining Canadian gas imports and increasing U.S. reliance on LNG imports, a commodity only available in a highly competitive market. The robustness of the North American gas resource base, particularly shale gas, coalbed methane and tight sands gas needs to be quantified.

Shale gas production, which dates from 1821 in the United States, is now rapidly increasing, accounting for approximately 5% of annual production. The U. S. Energy Information Administration estimates that shale gas production will overtake coalbed methane production by 2025, and will grow from the current 1 Tcf to 2.3 Tcf annually by 2030.

Shale gas is also an increasingly large component of future, technically recoverable resources. Both of these trends are due to improvements in exploration, completion, and production technologies, aided by wellhead price increases.

The latest Potential Gas Committee biennial assessment, (September, 2007), shows an overall increase of 18% (200 Tcf) for total U.S. gas resources. The bulk of this increase is for shale gas resources assessed in the Appalachian, Anadarko, Arkoma, Ft. Worth and Permian basins. This paper analyses shale gas future potential in light of past production, current proved reserves and the geological and economic realities of current and emerging Lower-48 U. S. plays.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas