--> ABSTRACT: Development of an Exploration and Exploitation Model for Methane in Carboniferous Age Coal and Carbonaceous Shale in the Mid-Continent and Eastern US and its Application to Other Basins, by Tedesco, Steven A.; #90155 (2012)

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Development of an Exploration and Exploitation Model for Methane in Carboniferous Age Coal and Carbonaceous Shale in the Mid-Continent and Eastern US and its Application to Other Basins

Tedesco, Steven A.
Running Foxes petroleum Inc., Centennial, CO.

The coal bed methane industry in the US is now over 30 years old and is in a mature stage for exploitation and development. The development of the San Juan and Warrior basins in the 1980s created a number of assumptions and models that were to be applied for exploration in other basins. Application of the exploration model's from the Warrior or San Juan basins have not generally been applicable to other areas, specifically those with Carboniferous age coals. Review of engineering, geologic and geophysical data there is specific criteria required for entrapment of gas contained in coals in the Mid-Continent and Eastern US to cause a viable economic resource. Many coal basins, such as the Illinois or Forest City basins, in the US do not have sufficient gas resource because they lack one or more of these criteria.

There are three types of gas produced from coal: thermogenic, biogenic and a mix of both. Biogenic gas requires a hydrologic system that introduces bacteria to the coal, digestion and methane generation as a waste product. An example of this is the coals in the Powder River Basin, Wyoming and is a separate model unto itself. The majority of the coal gas from Carboniferous coals in the Mid-continent and Appalachian regions is thermogenic or mixed. The presence of significant gas saturation in the Carboniferous coal or shale reservoirs is related to the proximity to the Ouachita-Marathon Orogeny age.

The Warrior, Appalachian, Cherokee and Arkoma basins coal bed methane fields are related to thrusting, expulsion and migration of low temperature hydrothermal fluids from the Ouachita-Marathon Orogeny. In these basins there are "sweet spots" that are related to their specific thermal and tectonic history. This talk will focus on the geologic characteristics needed to generate and contain significant gas within these Carboniferous age basins. This model can be used for an exploration model for other coal basins associated with orogenic belts.

 

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012