ABSTRACT
Exploration rationales, exploration techniques, and prospects are the key elements of EGSP’s ideal exploration strategy for the Devonian shales of the Appalachian, Illinois, and Michigan basins. An exploration rationale is a theory of how several known or suspected geologic circumstances may combine to create a favorable environment for the generation and accumulation of producible hydrocarbons. The unconventional nature of the Devonian shales as a natural gas resource demands shale-specific rationales. These are characterized by a hypothesized geologic mechanism for the creation of a natural fracture system, because fracture permeability is essential to shale production. Although fractures are a necessity, they alone are not sufficient. Hence, shale-specific rationales include supporting information on black shale thickness, kerogen content, thermal maturity, reported shows, production history, etc. Exploration rationales are area-specific, but generally not site-specific. Prospect development is the process by which site-specific prospects issue from areaspecific rationales. Exploration techniques are the means employed, short of drilling, to evaluate rationales and optimize local geologic factors in site selection.
The development of seven exploration prospects associated with the Newman Ridge and Greendale synclines in eastern Tennessee and southwestern Virginia illustrates EGSP’s exploration strategy.