The Sacatosa coalbed methane field: A first For Texas

In 2001, The Exploration Company (TXCO), San Antonio, announced the Sacatosa Coalbed Methane (CBM) Field in Maverick County. This field is the first CBM field in Texas (Fig. 1). The field is producing from bituminous coal in the Cretaceous Olmos Formation that outcrops to the west and dips easterly towards the Gulf Coast. The CBM field was developed in coalbeds whose general structure was known from log top data in pre-existing oil and gas wells drilled throughout the basin (Fig. 2). These preliminary data showed a large area of coal above 2000 ft depth with net coal thicknesses in the 5 to 30 ft range. Subsequently, TXCO and the USGS formed a cooperative research effort to determine the gas in place, rank, quality, extent and thickness of the Olmos coal in order to understand the resource potential of this newly emerging field.