An Update of Oklahoma Coalbed-Methane Activity

B. J. Cardott
Oklahoma Geological Survey, Norman, OK

About 1,200 wells have been drilled or recompleted specifically for coalbed methane (CBM) in Oklahoma from 1988 to April 1, 2001, according to the Coalbed-Methane Completions table in the Oklahoma Coal Database. About 60% of the wells were drilled on the northeast Oklahoma shelf, and about 40% were drilled in the Arkoma basin.

CBM completions on the shelf have been reported in 10 coal beds of Desmoinesian (Middle Pennsylvanian) age in 8 counties. Coal beds were perforated at depths-to-top of coal of 256–2,428 ft (78–740 m), averaging about 950 ft (290 m). Initial-potential CBM rates for wells on the shelf ranged from 0–260 thousand cubic feet of gas per day (MCFGPD), averaging 28 MCFGPD. Initial produced water on the shelf ranged from 0–1,201 barrels of water per day (BWPD; average of 61 BWPD).

CBM completions in the Arkoma basin have been reported in 5 Desmoinesian coal beds in 7 counties. The depths of these are 347– 3,726 ft (106–1,136 m; average of about 1,425 ft [434 m]). Initialpotential CBM rates for wells in the basin ranged from a trace to 595 MCFGPD (average of 88 MCFGPD). Initial produced water in the basin ranged from 0–147 BWPD (average of 15 BWPD). To date, 5 operators have completed 49 horizontal CBM wells in the Arkoma basin.

Ninety operators have been involved in the CBM play in Oklahoma, which spans 89 gas fields. CBM continues to be an attractive play in Oklahoma.

AAPG Search and Discovery Article #90903©2001 AAPG Mid-Continent Meeting, Amarillo, Texas