Study of an Iranian South-West Reservoir by Simultaneous Solution Method

Simultaneous solution is a useful method for interpreting and predicting undersaturated reservoirs performance. In this method oil in-place and water influx constant are estimated simultaneously. Thus, for preliminary study of a reservoir with unknown aquifer behavior, simultaneous solution method is a good method. Moreover, using this method initial oil in-place and water influx constant of the reservoir can be estimated. NISOC’s program used for simultaneous solution of the initial oil in-place and water influx constant of a southwestern Iranian undersaturated water drive with no gas cap reservoir. Van Everdingen-Hurst unsteady state model used to match aquifer behavior. Eventually, the best rD and tD has been estimated 2.5 and 2.5 respectively. Based on chosen rD and tD, initial oil in-place and water influx constant estimated about 1.13 MMMSTB and 4.54E6 bbl/psi respectively. A sensitivity analysis, also, has been done. Briefly, reservoir pressure and PVT data were the most sensitive parameters respectively. Sensitivity analysis also showed that oil in-place is more sensitive respect to reservoir pressure and PVT data than water influx constant.

Keywords:

Simultaneous solution , water influx constant , initial oil in-place , material balance