The effect of the pore space microstructure on hydrophobization of oil and gas reservoirs

Abstract

The results of theoretical and experimental studies of the effect of the microstructure of the pore space on the hydrophobization of oil and gas reservoirs are presented. A possible mechanism of formation of the microstructured wettability is described, which demonstrates that hydrophobization of the inner pore space in mixed wettability can be associated either with large or small pore sizes. It was proven experimentally that the process of hydrocarbon adsorption depended on the shape, size, and distribution of pores, the mineralogical composition (particle composition and size, presence of clay), as well as on the time of contact of hydrocarbons with the inner pore surface. The concept of the hydrophilic nature of rock prior to the migration of oil into it can be considered as accurate. However, as was shown in the experiments, oil could be present in the small pores (up to 10 μm), which was especially significant for the carbonate reservoirs.