Dynamic gas slippage: A unique dual-mechanism approach to the flow of gas in tight formations
A mathematical formulation, applicable to both numerical simulation and transient well analysis, describing the flow of gas in very tight (k < 0.1 md) porous media has been developed. Unique to this formulation is the dual-mechanism transport of gas. In this formulation gas is assumed to be traveling under the influence of two fields: a concentration field and a pressure field. Transport through the concentration field is a Knudsen flow process and is modeled with Fick's Law of diffusion. Transport through the pressure field is a laminar process and is modeled with Darcy's law (inertial-turbulent effects are ignored). The combination of these two flow mechanisms rigorously yields a composition, pressure and saturation dependent slippage factor. The pressure dependence arises from treating the gas as a real gas. The dynamic slippage derived from this formulation is found to be most applicable in reservoirs with permeabilities less than or equal to 0.01 md. The results from this study indicate that in reservoirs of this type, differences between recoveries after ten years of production using the dynamic slip described in this paper and constant slip approaches were as great as 10% depending on the initial gas saturation. If an economic production rate is considered, differences as great as 30 can be expected.
- Research Organization:
- Pennsylvania State Univ.
- OSTI ID:
- 5357359
- Report Number(s):
- CONF-8310121-
- Journal Information:
- Soc. Pet. Eng. AIME, Pap.; (United States), Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Vol. SPE12045; ISSN SEAPA
- Country of Publication:
- United States
- Language:
- English
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Dynamic gas slippage: a unique dual-mechanism approach to the flow of gas in tight formations
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Related Subjects
030200* -- Natural Gas-- Reserves
Geology
& Exploration
COMPRESSIBLE FLOW
DARCY LAW
FICK LAWS
FLOW MODELS
FLUID FLOW
FLUIDS
GAS FLOW
GAS SATURATION
GEOLOGIC DEPOSITS
KNUDSEN FLOW
MATHEMATICAL MODELS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PERMEABILITY
PRESSURE DEPENDENCE
RESERVOIR FLUIDS
RESERVOIR PRESSURE
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SATURATION
SEDIMENTARY ROCKS
SLIP FLOW