This study evaluates the differentiation and typification of dispersed organic matter (DOM) in the sedimentary cover section of the Baskhirsky arch using probabilistic-statistical methods. Differentiation of DOM is based on the following geochemical characteristics: content of organic matter and total organic carbon, percentage of chloroform, petroleum, alcohol-benzene bitumoids, content of humic acids and insoluble residue, characteristic of DOM transformation (bitumoid neutrality coefficient), bitumoid coefficient. As a result of typification, the DOM of the Baskhirsky arch is divided into 3 types: syngenetic, mixed and epigenetic (the most mobile DOM, which equates to micro-oil). Individual and complex prediction models of epigenetic DOM were built based on geochemical characteristics. It was found that the maximum influence on the differentiation of DOM is exerted by the following characteristics: bitumoid coefficient β and the value of insoluble residue (IR). To assess the effect of β and IR on the value of the complex probability of epigenetic substance manifestation, a detailed statistical analysis of changes in t-statistic values in the dynamics in different oil and gas bearing complexes was carried out. It was revealed that the system of DOM differentiation in carbonate oil and gas bearing complexes differs from terrigenous ones. With increasing complex probability, the value of t-statistic for bitumoid coefficient in all oil and gas bearing complexes steadily increases, which confirms the direct relationship between the value of bitumoid coefficient and oil and gas content. The value of IR has a high retention capacity and controls the process of DOM differentiation up to the value of complex probability equal to 0,55-0,6 shares of units, further, as the complex probability increases, the increase in the influence of bitumoid coefficient is noted throughout the section.
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