At present, method, developed at Gas Research Institute (GRI method), has an international status for assessing petrophysical properties of shale rocks. A comprehensive study of shale rocks based on this method revealed significant shortcomings, which in some cases become critical. The article proposes method for determining gas-saturated and open porosity, as well as gas, water and oil saturation of shale rocks on crushed samples. The method is adapted for main shale formations in Russia, as it is based on the investigation of more than 2700 core samples from 33 wells. Gas-saturated porosity of fresh samples (the core is in state of natural saturation) and open porosity of dry samples (the core is after extraction) are calculated based on bulk and grain densities. Grain density was determined by means of the gas injection porosimetry method. Two methods are proposed for determining bulk density of crushed fresh samples. There are the gas injection porosimetry method and the modified fluid saturation method. Authors of the article substantiate obligatoriness to determine bulk density of dry samples and suggest a method. Gas saturation of shale rocks was calculated based on gas-saturated and open porosity. Water saturation of shale rocks was determined by means of the direct method in the Zaks apparatus. Oil saturation of shale rocks was calculated by means of the material balance method of phases in void space. Approbation of offered method is carried out and main results of researches are given. Developed method can be used for routine research with high discreteness (1 sample for every 30-50 cm of core sampled). Applying of different fraction sizes for measuring bulk and grain densities, as well as water saturation, makes it possible to determine petrophysical properties independently of each other. All this allows to reduce time capacity of core investigation. The results obtained by means of the method can be used to identify promising intervals of reservoir, build correlation between well logging data and petrophysical core properties, calculate reserves, and also plan exploration work.
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