Swabbing Test Interpretation Using Nonlinear Regression in San Jorge Gulf Basin

摘要

In the San Jorge Basin in Southern Argentina swabbing test is the conventional testing technique used by YPF to evaluate production potential on those reservoirs that do not flow naturally to surface. During the well completion phase, a swabbing device is lowered subsequently to individually test each reservoir layer. These wells, which produce from multilayer formations, are later completed for commingled production. Accordingly, the swabbing test represents the only opportunity to measure dynamic properties for every individual layer. So far pressure transient analysis of such test has been limited to the use of conventional interpretation methods applied to the Infinite Acting Radial Flow portion, on those tests where such flow regime is observed. This can happen if a bottomhole shut in valve is used or if the shut- in period is given long enough time for the bottom hole pressure to reach conditions close to initial reservoir pressure. Unfortunately, both practices substantially increase the completion cost, which strongly affects well economics. As a result of this economic limitation, neither of such practices are applied on a routine basis so most of the time transient pressure interpretation is not performed.