Unsteady-state flow behavior for a well near a natural fracture
A mathematical model was developed to study the transient flow behavior for a well near an infinite conductivity vertical, nonintersecting, natural fracture in an infinite slab reservoir. A slightly compressible fluid was considered. Results when plotted as a function of a dimensionless time follow at early times a straight line of 1.151 slope characteristic of radial flow. After this radial flow period, the well pressure behavior starts to be affected by the natural fracture and this causes a negative pseudo-skin factor, which is a function of time, and becomes a constant for large values of time, giving a second 1.151-slope straight line. This pressure behavior is similar to the one predicted by the models of Warren and Root and de Swaan for a uniform naturally fractured reservoir. Results from interference tests, for reservoirs having a natural fracture, show that it is impossible to characterize uniquely the reservoir by means of the transient pressure test data alone. An integrated approach or transient pressure test data registered at several observation wells can be used for a unique characterization. From these tests, underestimation or overestimation of the reservoir parameters could result, depending on the location of the observation well relative to the natural fracture.
- OSTI ID:
- 7217311
- Report Number(s):
- CONF-761008-127
- Country of Publication:
- United States
- Language:
- English
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