MINERALOGICAL AND GEOCHEMICAL ASPECT OF NATURAL SHALE GAS PROBLEM (AT THE EXAMPLE OF BLACK ARGILLITES OF WESTERN UKRAINE)

Abstract

The material composition of the Lower Silurian potentially gas-bearing clay deposits in the Volyno-Podilska margin of the East European platform has been investigated in the context of shale gas deposits formation. The following factors played an important role in the formation of the gas content of the studied rocks: accumulation of Сorg in sediments, intensive diagenetic methane formation, ad-sorption of organic compounds by the surface of rock forming minerals and hydrophobization of pore space in rocks, absorption of methane and its gaseous homologues by the inclusions of or-ganic matter (kerogen), the effect of the so-called capillary condensation of gas, the concentra-tion of gas in a closed porous space. The theoretical models of geochemical and physico-chemical processes that occur during sedimentogenesis and lithogenesis of gas-bearing carbonaceous clays and siliceous-clay deposits (“gas-bearing shales”) and exploitation of shale gas deposits are proposed.