Computer microtomography (microCT) is one among the most dynamically developed methods used for studying oil and gas reservoirs structure. Combined with classical complex of lithological and petrophysical researches the microCT allows to conduct simultaneous study of rock composition and structure of pore space. Along with constructing volumetric 3D models, application of microCT provides a possibility of evaluating individual structural characteristics of rock in formation of residual water saturation