Coal-Bed Methane Resources in Arkoma Basin, Southeastern Oklahoma

Samuel A. Friedman

A major federal tax incentive for unconventional gas production has interested entrepreneurs, geologists, and engineers in the occurrence and distribution of coal-bed methane resources in the Arkoma basin. Because the methane is trapped in coal beds, geology of the coal resources also has received renewed attention.

The Arkoma basin contains most of the coal-bed methane resources in Oklahoma: 76% of the 7.9 billion short tons of the remaining, identified Middle Pennsylvanian coal resources of the state.

This paper briefly reviews previous estimates of coal-bed methane resources in Oklahoma and presents an updated estimate for Haskell and LeFlore Counties and a new estimate for Latimer County.

Rieke and Kirr indicated that 2.8 tcf of coal-bed methane is present in 10 coals in eight Oklahoma counties of the Arkoma basin, 500-3,000 ft deep. Iannacchione and Puglio estimated that a maximum of 1.5 tcf of coal-bed methane occurs in the Hartshorne coals in Haskell and LeFlore Counties from 500-3,000 ft deep.

The present investigation shows that the Hartshorne and 11 other coals contain at least 1.8 tcf of coal-bed methane resources, based on identified coal resources 500-3,000 ft deep in Haskell, Latimer, and LeFlore Counties. An additional 1.2 tcf of coal-bed methane resources occur in the Hartshorne and four other coals from 3,000-7,000 ft deep, based on assumed stratigraphic and thickness continuity.

Thus, a revised estimate indicates that Haskell, Latimer, and LeFlore Counties alone contain about 3 tcf of coal-bed methane resources in 12 coal beds from 500-7,000 ft deep. Undoubtedly additional coal-bed methane resources are present in the westernmost part of the Arkoma basin.

AAPG Search and Discovery Article #91025©1989 AAPG Midcontinent, Sept. 24-26, 1989, Oklahoma City, Oklahoma.