Developing geochemical criteria based on the research of Jurassic sediments to evaluate the productivity of intervals

Abstract

The article is devoted to the problem of improving the substantiation of the diagnostics of production Jurassic and Neocomian reservoirs in the West Siberian basin. We have formed the complex of geochemical investigations of core material to solve this problem. It includes extraction of bitumen with its material composition detection, thermal desorption and analysis of retained hydrocarbons. Using the obtained data, we have carried out a comparative analysis of Jurassic sediment intervals in two wells within one field. We studied the quantitative and qualitative characteristics of the hydrocarbon core fluid, determined the geochemical criteria of its mobility in reservoir conditions, namely the ratio of the naphthenic component to n-alkanes. Also, we carried out inter-well correlation of the relations of n-alkanes and isoprenoids, established the facies conditions of sedimentogenesis and oxidation-reduction conditions of the initial stage of organic matter fossilization. Based on the chromatograms of retained gases we determined the efficiency criteria of the interval such as benzene/n-hexane and toluene/n-heptane. Conclusions about the saturation of the studied intervals were confirmed by inspection test record. The results of the work showed that complex geochemical studies of the core can significantly increase the reliability of the diagnosis of the drilled sediments saturation.