The basic processes of secondary mineral formation, proceeding in water-oil contact zones, are considered. Structu - ral-mineralogical zonality of reservoirs in water-oil contact zones is given. The scheme of change of the oil-satureted reservoir in the water-oil contact zone is given. It is noted, that change of rocks at the water-oil contact often determines the formation of a secondary porosity: sedimentogene pores increase, intragrain pores of leaching are formed, degree of pores intercommunication, porosity and permeability of rocks increase.
