A geological model of a heterogeneous naturally fractured reservoir was constructed using geostatistical techniques. Single-well, interference and pulse tests were numerically simulated in this reservoir. The purpose was to compare the result obtained from conventional interpretation techniques with the properties of the geologic model in the drainage areas of the wells tested. Relevance of this work is shown by application to an actual field interference test.
The following were concluded in this study:
Conventional interpretation of simulated single well tests in heterogeneous naturally fractured reservoirs results in an effective permeability (ke) close to the arithmetic average of the effective permeability distribution in the drainage area of the wells,
Conventional pulse and interference test interpretations in naturally fractured reservoirs, in general, yield permeabilities larger than average reservoir permeability in the drainage areas of the wells. These results are consistent with our experience with actual field tests.
Single-well test transmissivity (keh/u) can be used in conventional single-porosity pulse and interference interpretation (e.g., PD vs. tD type-curve analysis) to obtain an approximate fracture storativity (ofctfh). Storativity in turn can be used to estimate fracture porosity in the drainage area.