Effect of Matrix Block/Grid Block Ratio on the Performance of Double Porosity Simulators
Abstract/Contents
- Abstract
- The current approach to double porosity simulation provides for the solution of combined properties of matrix blocks contained within a finite-difference grid cell. This report examines the effect of the matrix block-to-grid block size ratio on the performance of double porosity simulators.Fine grid single-porosity simulations were conducted for a field-scale water injection process and for a single matrix block undergoing gas gravity drainage. Results from double porosity simulations were matched to the fine grid solutions by altering the matrix block shape factor. The shape factor used to match the five-spot water injection problem agrees closely with the formulation proposed by Thomas et al. This formulation has as its characteristic length the distance to the centroid of one of the equilateral pyramids within a cube. The shape factor used to match the single-block gas gravity drainage problem is the same as that derived previously for 1D vertical displacement. This formulation has the length of a side of a cube as its characteristic length.The matrix block-to-grid block size ratio, R,,, was defined as the number of matrix blocks contained within a single finite-difference grid cell. The effect of the number of matrix blocks per grid cell was investigated for a field-scale five-spot quadrant example and for a reservoir undergoing gas gravity drainage. Matrix block size was kept constant for all runs and grid block size was altered to conform to various values of the matrix-to-grid block ratio, RmaSimulation results for the five-spot example showed some degree of sensitivity to grid dimensioning relative to matrix block size. The degree to which results were sensitive to the matrix block-grid block ratio was investigated as a function of injection/production rates, matrix permeability, and the matrix block shape factor. Sensitivity to differences in the R m , ratio increased for systems having small matrix block dimensions and large shape factors, and for systems having high matrix permeabilities. The effect of differences in R,, was found to increase slightly as field injection/production rates were lowered.The field-scale gas gravity drainage example showed no sensitivity to the number of matrix blocks per finite difference grid cell for similar variations in Rma. Future study of the sensitivity of results to changes in matrix permeability, injection/production rates, and fluid properties may shed additional light on this finding.
Description
| Type of resource | text |
|---|---|
| Date created | June 1988 |
Creators/Contributors
| Author | Froehlich, Joan E. |
|---|---|
| Primary advisor | Aziz, Khalid |
| Degree granting institution | Stanford University, Department of Petroleum Engineering |
Subjects
| Subject | School of Earth Energy & Environmental Sciences |
|---|---|
| Genre | Thesis |
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Preferred citation
- Preferred Citation
- Froehlich, Joan E. (1988). Effect of Matrix Block/Grid Block Ratio on the Performance of Double Porosity Simulators. Stanford Digital Repository. Available at: https://purl.stanford.edu/kr020md4080
Collection
Master's Theses, Doerr School of Sustainability
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