Estimation of quantitative criteria of carbonate reservoirs of triassic deposits

This paper discusses the boundary values of the reservoir properties of carbonate rocks of the Triassic sediments of South Mangyshlak, which are important for the interpretation of production geophysical data and for perforating and blasting operations. In terms of lithological composition, Triassic deposits are represented by two types of commercial reservoirs – terrigenous and carbonate. Carbonate reservoirs are localized in the volcanic-dolomite and volcanic-limestone strata of the Middle Triassic. These rocks are characterized by a complex type of reservoir: porous-fractured, porous-cavernous and fractured. Sediments of the Upper Triassic occur with erosion on the Middle Triassic sedimentary complex and are represented by alternating tuffaceous, silt-sandy and mudstone rocks. Polymictic sandstones are oil-saturated to varying degrees; oil deposits are confined to them. To substantiate the quantitative criteria of the reservoir, the results obtained during special laboratory studies of the core were used. Filtration studies were carried out, where physical and hydrodynamic characteristics were determined when oil was displaced by displacing reagents. The obtained parameters were used to construct correlations “collector – non-collector”. Using the relationships between the reservoir properties of the reservoir, the dependence of the porosity and permeability on the residual water content, as well as open porosity and permeability on the dynamic porosity, the boundary values were determined.