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FP5

ICBM Résumé de rapport

Project ID: ENK6-CT-2000-00095
Financé au titre de: FP5-EESD
Pays: United Kingdom

A new formulation for changes in the effective horizontal stress

The cleat permeability of coalbeds has been shown to vary exponentially with changes in the effective horizontal stress acting across the cleats, through the cleat volume compressibility, which is analogous to pore compressibility in conventional hydrocarbon reservoir rocks.

A new formulation for changes in the effective horizontal stress (under uniaxial strain conditions) accounting for matrix swelling as well as shrinkage is developed. The model has been validated using field primary recovery permeability data from coalbed methane wells at two different sites in the San Juan Basin.

Using the reservoir parameters calibrated from the primary recovery field data, permeability changes during enhanced recovery by injecting CO2, N2 or flue gas may be estimated. In particular, it is shown that matrix swelling caused by CO2 adsorption could lead to a two-order of magnitude reduction in coalbed permeability.

Reported by

Imperial College London
Department of Environmental Science and Technology, South Kensington Campus
SW7 2AZ London
United Kingdom
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