L.S. Borisova
A.N. Fomin

: Petroleum Chemistry

By studying the organic matter (OM) from the Mesozoic deposits of the Tyumen superdeep well (SG-6) as an example, deep zoning in the distribution, composition, and structure of heterocyclic components of the dispersed OM in catagenesis has been revealed. During mesocatagenesis, the composition of asphaltenes undergoes directed changes similar to those found for debitumenized OM. During apocatagenesis, polymerization and condensation of asphaltene molecules and their transition to an insoluble form as a new type of kerogen occur. Their lighter part is involved in structural redistributions inside resins and hydrocarbons (HC) and the formation of gases; there is a relative increase in the concentration of resins and HC (in wt % of residual bitumens). This circumstance should be taken into account when predicting the generation potential of OM and the composition of hydrocarbon fluids formed during catagenesis.