Fluid flow in cracks as related to low permeability gas sands
Conference
·
· Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:5233284
A problem in formation evaluation of tight gas sands is that their permeabilities are sometimes surprisingly sensitive to variations in overburden pressure. Photomicrographs of pore casts show an interconnected system of sheet pores which are somewhat like the surfaces of a randomized honeycomb. A mathematical relation for predicting the pressure dependence of flow rate in sheet pores has been derived from the dimensions of the pores and the elastic constants of the matrix. The equation has been validated by measurements on artificial media containing cracks of known dimensions in glass and concrete. The observed pressure sensitivity of the gas sands used in this study requires the aspect ratio of the pores (in this case, the ratio of average large dimension to sheet thickness) to be greater than 100. Aspect ratios have been determined by taking the large dimension from photomicrographs of pore casts or grain size and thickness from mercury injection pressure or from the slope of a plot of apparent permeability vs. the reciprocal of gas density. The latter gives the effusive contribution to gas flow from which the pore size can be calculated. The two methods for measuring pore size give satisfactory agreement. The aspect ratios for the sheet pores in tight gas sands are large enough to explain the dependence of permeability on overburden pressure.
- Research Organization:
- New Mexico Inst. of Mining Technology
- DOE Contract Number:
- AS19-80BC10216
- OSTI ID:
- 5233284
- Report Number(s):
- CONF-830305-
- Conference Information:
- Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Journal Volume: SPE/DOE 11623
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fluid flow in cracks as related to low-permeability gas sands
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Journal Article
·
Sun Mar 31 23:00:00 EST 1985
· SPEJ, Soc. Pet. Eng. J.; (United States)
·
OSTI ID:6502356
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·
OSTI ID:6982932
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OSTI ID:6532925
Related Subjects
03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
BUILDING MATERIALS
CONCRETES
CRACKS
CRYSTAL STRUCTURE
DRILL CORES
EQUATIONS
EVALUATION
FLOW RATE
FLUID FLOW
GAS SATURATION
GEOLOGIC DEPOSITS
GLASS
MATERIALS
MICROSTRUCTURE
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
PERMEABILITY
POROSITY
PRESSURE DEPENDENCE
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SATURATION
SEDIMENTARY ROCKS
SYNTHESIS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
BUILDING MATERIALS
CONCRETES
CRACKS
CRYSTAL STRUCTURE
DRILL CORES
EQUATIONS
EVALUATION
FLOW RATE
FLUID FLOW
GAS SATURATION
GEOLOGIC DEPOSITS
GLASS
MATERIALS
MICROSTRUCTURE
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
PERMEABILITY
POROSITY
PRESSURE DEPENDENCE
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SATURATION
SEDIMENTARY ROCKS
SYNTHESIS