The role of concentrations variability of organic matter in kerogenic shale defluidisation on the catagenic depths

Abstract

The Baltic kerogenic shale – kukersites (О2kk) were considered high-carbon marls which consist of three rock-forming components: organic matter (kerogen), carbonates and terrigenous material. As example used are data of the other high-carbon rocks. It is shown that increased concentrations of organic matter predetermine a number of features of these rocks (reduced density, reduced strength, etc.). The concentrations variability of the organic matter makes conditions the heterogeneity of the intraformational space, the anisotropy of many parameters, as well as the manifestation unevenness of the fluid-generation and evacuation capabilities. It was found that in kukersite shales fluid-generating properties can appear at the earliest stages of catagenesis. The role of areas with the maximum qualities of organic matter in the defluidisation of the shale coals is emphasized: here the more intensive generation of gas-liquid products and increased strength contribute to the earlier formation of drainage microcracks and fluid fractures. The appearance of shrinkage cracks due to catagenic losses of organic matter and usually uneven volume contraction and due to fluidgenerating shale coals is substantiated. The possibility of fluid-generating shale coals losing it lithological individuality during of it defluidisation is found out. Keywords: organic matter; oil shale; kukersite; defluidization; catagenesis; hydrocarbons.