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Behavior of coal-gas reservoirs. [7 refs]

Technical Report ·
OSTI ID:7254029

Gas occurs in coalbeds in an adsorbed and a free gas state. Adsorbed gas is stored in the micropore structure and its transport is governed by Fick's law. The free gas occurs in the fracture system and flows according to Darcy's law. These two modes of mass transport are interdependent. Production decline curves of coal-gas wells are of the constant percentage decline type and, thus, show no indications of flow characteristics peculiar to coal-gas reservoirs. The effectiveness of surface boreholes as a degasification scheme depends upon both good fracture permeability and a high fracture density. Conventional methods of reservoir engineering analysis are not applicable to coalbeds.

Research Organization:
Bureau of Mines, Pittsburgh, PA (USA)
OSTI ID:
7254029
Report Number(s):
BM-TPR-10
Country of Publication:
United States
Language:
English