Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data
Figure 9
Ratio of SP change to pressure change as a function of time for KF-3 observation on May 13, 2007 (a) and KF-1 observation on May 14, 2007 (b). Two records for each electrode are drawn with different “static” SP values: one is with an average value over interval between 25 and 15 minutes before the valve opening and another is with an instantaneous value just at the valve opening at time zero. The differences between the two curves are relatively small even for earlier times than 100 seconds in the results shown here. At times pointed by *a, *b, and *c, all electrodes in wells KF-1 and KF-3 were suffered from a shift or a short-term disturbance. If the “double-porosity” model is applied to the KF-1 observation, the time required for pressure equilibration between the fracture and matrix regions is estimated as seconds.
