Reservoir Engineering in Coal Seams: Part 1—The Physical Process of Gas Storage and Movement in Coal Seams
- 1 February 1987
- journal article
- Published by Society of Petroleum Engineers (SPE) in SPE Reservoir Engineering
- Vol. 2 (01) , 28-34
- https://doi.org/10.2118/12514-pa
Abstract
Summary: This is the first of two papers concerning the movement of gas in coal seams. It deals directly with the physical behavior of the coal seam as a reservoir. Coal seams show considerable differences in behavior from normal porous gas reservoirs in both the mode of gas storage and permeability characteristics. Most of the storage of gas in coal is by sorption into the coal structure, while the coal permeability is cleat-(fracture-) or joint-controlled and may vary over a wide range during production. This permeability fluctuation is not solely a phase relative permeability effect, but is rather a result of the opposing effects of effective stress increase with fluid pressure reduction and shrinkage of the coal. Reducing fluid pressure tends to close the cleats, reducing permeability, while shrinkage tends to open them.Keywords
This publication has 4 references indexed in Scilit:
- Effect of stress on permeability of coalInternational Journal of Rock Mechanics and Mining Sciences, 1975
- Development of techniques and the measurement of relative permeability and capillary pressure relationships in coalInternational Journal of Rock Mechanics and Mining Sciences, 1974
- The determination of the complete state of stress in rock in a single borehole—Laboratory and underground measurementsInternational Journal of Rock Mechanics and Mining Sciences, 1968
- Rock Fracture Spacings, Openings, and PorositiesJournal of the Soil Mechanics and Foundations Division, 1968