The article presents experimental and theoretical study of the influence of the microstructure of the pore space on the hydrophobization oil and gas reservoirs. A possible mechanism of formation of microstructural wettability are described. The adsorption of the hydrocarbons can be both in small and large size pores. It was experimentally proved that hydrocarbon's adsorbtion depends on the form, size and distribution of pores, type of the mineral surface, how long oil was in contact with the mineral surface.