Influence of micro-heterogeneity of fractured-porous reservoirs on the water flooding mobilization law

The storage space of fractured-porous reservoirs includes a variety of primary pores, secondary pores and fractures and has strong micro-heterogeneity. When water injection is used for development, the development effects of different development areas are significantly different. In order to clarify the influence of micro-heterogeneity on the water flooding mobilization law, three types of glass etching models were designed according to actual oilfield. Water flooding experimental research was conducted on the models. The results show that the mobilization mode changes from a uniform mobilization mode to a network mobilization mode as the heterogeneity of the pore system increases. The recovery degree of pore throat structure I model is 31.8% lower than that of pore throat structure II model. The fracture system of fractured-porous reservoirs is shown as a finger-like mobilization mode along with the fractures. This model has a 19.8% lower recovery degree than pore throat structure II model but 12% higher than pore throat structure I model. The water flooding law was studied from the utilization order of large and small pore throats, and the shape of water flooding front was compared and analyzed, which provides a guiding significance for the enhanced oil recovery of fractured-porous reservoirs.