Features of litho-mineralogical consistence of frolov formation (on the example of Severo-Krutinskoe oil field)

The lithological features of the productive formation AC5 in frolovskaya suite of the barremian stage of lower cretaceous, according to core material studies, selected from the potentially productive interval 2337,00-2351,00 m of production well №204 of Severo-Krutinskoe oil field are described in the article. The lithological reservoirtype, zones of the deterioration of reservoir properties in connection with secondary mineral formation were set.
Materials and methods
Optical-microscopic analysis, grain size measurement, determination of reservoirporosity and permeability, fluorescence analysis, X-ray diffraction analysis, electron microscopy.
Results
As a result of several studies, the lithological features of the productive formation AC5 in frolovskaya suite of the barremian stage of lower cretaceous were analyzed, according to core material of three samples.
Сonclusions
The quartzose graywackes with high content of organic coalifield are considered to be the lithological types of the reservoir. Pore-filling of the grains is the reason for high reservoir porosity and permeability. The reservoir porosity and permeability, according to geophysical and core analysis, deteriorates downsection. Reduced permeability and porosity reduction, to a less degree, is connected with progressing of secondary mineral formation. The influence of secondary changes is the reason for the lack of the clear differentiation of selected lithotypes petrophysical properties.