As reported by the American Gas Association, the U.S. natural gas resource base is larger than previously estimated, with 1,525 trillion cubic feet (Tcf) in total natural gas resources as of the end of 2006—the equivalent of 82 years of production at current rates, according to a biennial report on long-range supplies of natural gas released June 18 by the Potential Gas Committee (PGC), Colorado School of Mines.

According to the PGC, this is the largest volumetric increase and percentage increase in the PGC's biennial estimates since 1968. Much of the resource growth can be attributed to U.S. onshore areas where success in extracting natural gas from shales and coal seams has resulted in revised assessments of existing resource plays and inclusion of new opportunities. This has been the case in numerous Mid-Continent production areas such as the Arkoma, Anadarko, Fort Worth and Permian basins. According to the report, additional growth in the resource base has also resulted from new data from the Gulf Coast, Rocky Mountain and Pacific areas.

The PGC report indicates the total size of the resource base has increased since the committee's last report at year-end 2004, even though 36 Tcf of natural gas have been drawn down since that time.

Factoring in the past two years of production, the PGC actually has increased its estimate of the U.S. natural gas resource base with each successive report over the last 16 years, primarily due to new geologic information, technology developments and changing economics. 

The PGC is comprised of members from the natural gas industry, government agencies and academic institutions. The Committee functions independently, but with the guidance and technical assistance of the Potential Gas Agency of the Colorado School of Mines. More details are available at website.