Nonstatic pressure history analyses for gas reservoirs
A method has been developed for using nonstatic pressure measurements directly in gas reservoir material balances composed of various energy mechanisms. Applying this method leads to simultaneous determinations of the reservoir p history, gas in place, and other parameters relevant to water influx and effective compressibility. Well-known methods of determining average static pressure, /sup -/p, have at least two shortcomings: an estimation of reservoir shape and an often-neglected implicit relationship between /sup -/p and the viscosity compressibility product. Errors resulting from these deficiencies are minimized by the proposed method through a simple coupling of the well-known pseudosteady-state flow and material-balance equations. The solution of this coupling is obtained through nonlinear regression, and it allows simultaneous evaluations of gas initially in place, static pressure history, and several other reservoir parameters. These parameters can include the initial reservoir pressure, a stabilized gas-deliverability constant, the effective compressibility, aquifer diffusivity, and aquifer volume plus water-influx constants. The results of applying the method to six published cases are presented to illustrate the utility of the method.
- Research Organization:
- Otis Engineering Corp.
- OSTI ID:
- 5674284
- Journal Information:
- SPEJ, Soc. Pet. Eng. J.; (United States), Journal Name: SPEJ, Soc. Pet. Eng. J.; (United States) Vol. 23:2; ISSN SSPJD
- Country of Publication:
- United States
- Language:
- English
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Nonstatic pressure history analyses for gas reservoirs
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Related Subjects
030200* -- Natural Gas-- Reserves
Geology
& Exploration
AQUIFERS
COMPRESSIBILITY
DIFFUSION
EQUATIONS
FLUID FLOW
GEOBAROMETRY
GEOLOGIC DEPOSITS
MATERIAL BALANCE
MATHEMATICS
MECHANICAL PROPERTIES
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PARAMETRIC ANALYSIS
PRESSURE MEASUREMENT
REGRESSION ANALYSIS
RESERVOIR PRESSURE
RESOURCES
SHAPE
STATISTICS
STEADY FLOW
VISCOSITY
VOLUME
WATER INFLUX