Despite the modern trends for the decarbonization of power engineering, transportation, and industry, fossil fuels remain in high demand. On the other hand, the gas and oil industries are also interested in energy efficiency and reduced environmental impact. Drilling of the wells is one of the most environmental danger processes, and reducing the number of wells is an important task that also provides an increase in the overall energy efficiency of the oil/gas mining technological process. Deposit exploration is a necessary part of the petroleum mining industry that determines the presence of fuel resources. The reliable and fast identification of the oil/gas deposits allows for a decrease in the number of drilled research holes. The authors of this article investigated the depth distribution of the hydrocarbon and non-hydrocarbon components of dispersed gas sampled from the cores of West Siberia shallow wells to quickly refine the boundaries of the layers using a priori information in the form of geochemical correlation. The correlations were established based on the amount of methane, the sum of homologs of methane, hydrogen, and olefines. The results show a decrease in the concentrations of gas components at the boundaries of layers with different lithologies. The term "geochemical seal" is introduced to describe such a phenomenon.

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.

Low-pressure gas production is one of the most important tasks in gas field development. To estimate the reserves of previously uninvolved reservoirs with low reservoir properties, it is necessary to analyze available geological and geophysical information for the subsequent creation of a three-dimensional geological model. Based on this model, a filtration model will be built, which allow calculating the flow rates of both actually drilled and designed wells for the entire development period. The model is built on the basis of small amount of information content, but the modeling results sufficiently reflect the presence of a zone of poorly saturated part of the Cenomanian gas reservoir, and structural and petrophysical features of the reservoir in the territory. As a result of the conducted research, the low pressure gas reserves at the Yamburgskoye field were calculated. The calculations, which are given in the article, are correct and don't contradict the Regulations on the creation of permanent geological and technological models of oil and gas and oil fields (RD 153-39.0-047-00).