The Influence of Microscopic Pore Structure on Microscopic Residual Oil in Sandstone Reservoir

Abstract

The distribution of microscopic residual oil varied according to the character of rock pore structure. How pore structure effect residual oil distribution is still an unresolved problem. In this paper, different origin samples were collected, then the characters of microscopic pore structure was analyzed with mercury injection curves, casting thin sections and SEM. The character of microscopic residual oil was observed with fluorescence thin sections. The study showed that after strong water flooding, the microscopic residual oil was mainly composed of intergranular type and cluster type residual oil, but the proportion of different type of residual oil varied according to different microscope pore structure. the smaller the radius of pore structure is, the higher the proportion of intergranular type and cluster type remaining oil is, but the lower the proportion of corner type, membranous type and throat type is.