Microscopic on the Effect of Diagenetic Evolution of Different Lithologies on Reservoir Performance of Dense Sandstone Reservoirs

  • Shu Yan, Ji Li, Shuang Liang


Tight sandstone is special sandstone with characteristics of compact lithology, low porosity, and low permeability, low-pressure coefficient of gas reservoir, low trap range and low natural productivity. Tight sandstone gas is an important class of unconventional natural gas reservoirs that exist in many basins around the world and have large reserves. With the progress of science and technology, the degree of oil and gas exploration and development has been continuously improved. People are gradually aware of the huge economic value of tight sandstone reservoirs, but this also makes it more and more difficult to explore oil and gas. Therefore, it is important to fully understand the basic characteristics of tight sandstone reservoirs and their physical influencing factors to identify the genesis of relevant tight sandstone reservoirs and the diagenetic evolution during geological history. By means of microscopic study and quantitative statistics of various thin sections under microscope, combined with experimental analysis and testing methods such as scanning electron microscopy, thin section and inclusion incineration observation, cathodoluminescence, inclusion homogenization temperature and laser Raman probe composition analysis, the tight sandstone of reservoir was studied in combination with the diagenetic evolution of different lithologies. The basic difference between compact reservoir and conventional reservoir is recognized through research, and the compact reservoir is unconventional reservoir, but it has both unconventional and conventional attributes. By studying the control and influence of deposits, diagenesis and fractures on pore throat characteristics and physical properties of tight reservoirs, evaluation parameters are screened from reservoir performance, flow ability, control factors and result verification, and comprehensive evaluation criteria for tight reservoirs are established, which provides a basis for the identification of high-quality reservoirs.