This paper describes the studies covered the most typical for the region productive reservoirs containing pelitic, aleuritic, fine-grained sand and medium-grained sand fractions. The results of changes in the content of fractions depending on the depth are presented in the form of circular diagrams of changes in porosity, fractional composition and mechanical compaction of deposits. The regularities of compaction of the pore space of productive reservoirs in-depth and the relationship between the specific surface of the pore space and oil saturation were established. The results are based on statistical estimates of the impact of individual fractions (including dominant fractions) on porosity in various reservoir rock types. In particular, the obtained data showed that an increase in the content of the dominant fraction, as well as the 0.175 mm fraction in clay-sand siltstones, leads to an increase in porosity. İn the group of sandy-clayey siltstones, the porosity effect of both the dominant (0.055 mm) and larger (0.25 mm) fractions is negative. Finally, in sandy loam, the effect on the porosity of the dominant (fine 0.055 mm) and subordinate (more than 0.175 mm) fractions, as well as in the group of clayey-silty sands, is opposite. Thus, an increase in the content of the fine (0.055 mm) fraction in the sandy loams leads to a decrease in porosity, and an increase in the content of the larger fraction (0.175 mm) increases the value of porosity.

Keywords: intergranular porosity, terrigenous types of reservoirs, grains packing, particle size  nalysis, dominant fractions of rocks 

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