Geochemical characteristics of oil and gas source rocks of the southern part of the Pre-Ural foredeep

UDK: 553.98.061.17
DOI: 10.24887/0028-2448-2021-5-45-49
Key words: Pre-Ural foredeep, geology of oil and gas, geochemistry, organic matter, oil, gas, source rocks
Authors: A.S. Monakova (Gubkin University, RF, Moscow), A.V. Osipov (Gubkin University, RF, Moscow), V.I. Ermolkin (Gubkin University, RF, Moscow), L.M. Bondareva (Gubkin University, RF, Moscow)

The article presents the results of studies of the oil and gas source properties of rocks of the Paleozoic complex, distributed within the southern part of the Pre-Ural foredeep. Despite the fact that work on the study of the southern part of the Pre-Ural foredeep has been going on for a relatively long time, the territory today remains underexplored by modern methods and the actual data on the area are very fragmentary. Today, the involvement of new facilities that will change the structure of hydrocarbon reserves is highly relevant, and there are prerequisites for the opening of such facilities in the region. There are four oil and gas complexes in the study area: Lower Permian, Visean-Bashkirian, Frasnian-Tournaisian and Lower Devonian-Frasnian. Oil and gas source rocks of all oil and gas complexes were characterized by 299 samples from 27 wells drilled in the study area. Also, 86 samples of rocks of the Silurian age were studied, which were taken in a quarry near the city of Kuvandyk. These rocks were also identified as source rocks. All samples were studied by the Rock-Eval method, which made it possible to determine the spectrum of parameters reflecting the qualitative and quantitative characteristics of the organic matter of the rocks. For all oil source rocks of oil and gas bearing complexes, maps of variability of geochemical parameters were built over the area. For the total organic carbon content and hydrogen indices in mature source rocks, calculations of their initial contents were carried out. Most of the samples studied are excellent in organic carbon content. Most of the samples of oil source rocks are characterized by II and II / III types of kerogen, therefore, they generated oil and gas. As a result of the research, maps were created on the distribution of the geochemical parameters of the Lower Permian oil and gas complex as the most studied one. It was found that the catagenetic transformation of organic matter increases towards the southern part of the study area.


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