A multiscale study on the effects of dynamic capillary pressure in two-phase flow in porous media

Abstract

Capillary pressure is usually considered as a function of the rock and fluid properties, and saturation. However, recent studies have shown that capillary forces also are a function of the rate of change of saturation. Moreover, although it was observed that dynamic forces are highly scale dependent, the role of these effects in large-scale flow practices is still unclear. In this study, using an innovative numerical simulation approach, the impact of the mentioned parameters was studied in a highly heterogeneous oil reservoir that is under waterflooding process. It is observed that the role of dynamic capillary pressure, using routinely measured dynamic capillary coefficient values, is not important in large-scale problems. However, it would be important in the higher capillary coefficient values that are several orders of magnitude larger than the values reported in previous experimental studies. Furthermore, the role of rock heterogeneity is discussed and it is shown that neglecting the dynamic capillary effects in heterogeneous media may lead to misleading results in the prediction of the injection front behavior in the reservoir. The dynamic capillary effects, by lowering the imbibition capillary pressure in the front, leads to more frontal movement of the injection fluid. Also, it is shown that the dynamic effects are more sensible at points close to the injection wells in homogenous reservoirs, but, in the heterogenous models it is more dependent on rock properties than the distance from the injection wells.