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Permeability Model for Coal and Other Fractures, Sorptive-Elastic Media.

DE2007911728

Publication Date	2006
Personal Author	Robertson, E. P.; Christiansen, R. L.
Page Count	13
Abstract	This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic media, such as coal, under variable stress conditions commonly used during measurement of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is also designed to handle changes in permeability caused by adsorption and desorption of gases from the matrix blocks. The model equations can be used to calculate permeability changes caused by the production of methane from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model can also be used as a tool to determine input parameters for field simulations by curve-fitting laboratory-generated permeability data. The new model is compared to two other widely used coal permeability models using a hypothetical coal with average properties.
Keywords	Gas sorption Permeability Coal Models Methane Sorptive properties Carbon dioxide
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Idaho National Lab., Idaho Falls.; Colorado School of Mines, Golden.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Colorado School of Mines, Golden. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200802

Permeability Model for Coal and Other Fractures, Sorptive-Elastic Media.

Permeability Model for Coal and Other Fractures, Sorptive-Elastic Media.
DE2007911728

Publication Date	2006
Personal Author	Robertson, E. P.; Christiansen, R. L.
Page Count	13
Abstract	This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic media, such as coal, under variable stress conditions commonly used during measurement of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is also designed to handle changes in permeability caused by adsorption and desorption of gases from the matrix blocks. The model equations can be used to calculate permeability changes caused by the production of methane from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model can also be used as a tool to determine input parameters for field simulations by curve-fitting laboratory-generated permeability data. The new model is compared to two other widely used coal permeability models using a hypothetical coal with average properties.
Keywords	Gas sorption Permeability Coal Models Methane Sorptive properties Carbon dioxide
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Idaho National Lab., Idaho Falls.; Colorado School of Mines, Golden.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Colorado School of Mines, Golden. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200802