Evaluation of carbonate-clay cement impact on the permeability factor of reservoir rocks by geophysical data

Abstract

Control over the process of reservoir flooding provides an opportunity to conduct efficient and rational operation of hydrocarbon deposits. Detailed monitoring of the flooding process requires the creation of geologicalfiltration models. The basis of the reservoir filtration model is the permeability factor; its reliability depends on various factors. It was proved that the reliability of permeability factor determination of Hidnovytske field is significantly affected by carbonate content. The research to determine connection of the natural gamma field intensity with the radiation capture of neutrons intensity on the basis of geological and geophysical borehole survey of the Hidnovitske gas field was performed. The model of reservoir rock neutron properties reflects the hydrogen content in the pore space and the characteristic of the mineral composition of the reservoir rock cement. This characteristic makes it possible to use neutron gamma logging to evaluate the carbonate content impact in determining the permeability factor. To evaluate the carbonate content, it was suggested to use relative parameter G, indicating the part of the rock
dispersed fraction in the unit of hydrogen content. According to the results of laboratory measurements on core material and geophysical data of radioactive logging, the dependence of parameter G value on carbonate content was developed. The obtained dependence will allow to determine the proportion of carbonates in clay cement by parameter G value and correct the equation to determine the permeability factor.