Influence of processes of the formation of authigenic clay minerals of terrigenous rocks on reservoir properties: Evidence from the rocks of the Vartov Arch

Filtration-capacity properties of terrigenous reservoir rocks significantly depend on catagenetic transformations of clay minerals. Results of our research revealed the authigenic nature and formation stages of kaolinite and chlorite. The volume and shape of pore space define the morphology of clay particles. Depending on the pore volume, kaolinite crystallizes either as thick tabular aggregates or as fan-shaped intergrowths. The formation of authigenic clays in pores of terrigenous reservoirs decreases filtration-capacity properties of rocks with low permeability and, conversely, increases filtration-capacity properties of rocks with high primary permeability and large pore volume.