COMPLEXITIES IN THE ANALYSIS OF PRESSURE-TRANSIENT RESPONSE IN FAULTED NATURALLY FRACTURED RESERVOIRS

Pressure-transient modeling for bulk testing of naturally fractured systems requires consideration of the effect of no-flow barriers on the pressure response. This study shows that, depending on the distance to the fault and under certain reservoir conditions, the presence of a linear barrier can affect the duration and the nature of the transition interval and estimation of interporosity parameters and reservoir transmissivities. Typical semilog plots for naturally fractured reservoirs (NFR's) may not be observed unless the fault is at a large distance away from the test well. In most cases, a double reflection is predicted-i.e., fracture response and the total system response. A correlation is developed to estimate the distance to the fault from the early fault reflection data. A critical wellbore storage constant can also be identified above which the detection of the fault becomes impractical.