Key words: permeability, nanopermeable reservoirs, core samples, GRI method, steady-state permeability.
The subject of the research is the core samples of Late Jurassic nanopermeable deposits of the Bazhenovskaya suite of one of the fields of the Tomsk region (Western Siberia). A comparative analysis of the available laboratory methods for determining the porosity and permeability of the core samples , including the method for estimating the permeability of crumbled core (GRI method), is carried out. The results of studies are applicable at the calculation of hydrocarbon resources in deposits of the Bazhenovskaya suite and evaluation of potential wells flow rates. It is shown that natural fracturing of argillaceous-siliсitic deposits of the Bazhenovskaya suite has decisive influence on reservoir properties , increasing the permeability by 2 - 6 orders , and the porosity - by 50 % on average. Noted allows to formulate a strategy of further investigations of petrophysical properties of the Bazhenovskaya suite sediments as characteristic of mainly fissuring void.
