Ermolova info 3.2019 | oilandgasgeology

Якорь 1

T.E. Ermolova, I.A. Mushin, A.A. Stupak, B.K. Frolov, G.A. Oksman,
N.Yu. Kholmyanskaya

Opportunities for new oil and gas bearing objects prospecting in the Upper Tournaisian-Visean terrigenous formations of eastern part of Volga-Urals Petroleum Province on the basis of integrated sedimentological and geoseismic studies

DOI 10.31087/0016-7894-2019-3-67-85

Petroleum potential of polyfacies Upper Tournaisian-Visean terrigenous rock association in the eastern regions of Volga-Urals Petroleum Province are focused on prospecting of stratigraphic and combination types of traps. Such an approach is especially relevant for depressions in the pre-Urals Foredeep; ill-defined structural factor, area reduction, and complicated morphology of terrigenous series distribution are typical of them. Substantiation of prospects in the regional stage reduces to identification and mapping of zones having different structure of the deposits, which responds to depositional environments and processes, and also lithological objects — prospective hydrocarbon traps. Updating structure of each horizon and building the respective maps is based on integration of lithofacies, sedimentological, and geoseismic analyses, including interpretation of synthetic regional seismic cubes generated using 2D seismic data. Using the thickness map of the series, boundaries of main paleotectonic zones of eastern regions of Volga-Urals petroleum region are updated. References of section structure are developed, and geological and geophysical characteristics of lithological objects having different genesis is presented. Parameters of total and net thickness, porosity, shale/sand ratio are calculated, and isopach maps are created for sands within the horizons. Seismic facies are identified, which are fitted to reference well columns both on 2D seismic time sections and in the slices of regional synthetic paleo-cubes at the levels better matching to the intervals of target horizons (Kos’vinsky-Radaevsky, Bobrikovsky, and Tul’sky). As a result of integrated analysis in accordance with references accepted for different depositional zones, structural maps and maps of promising zones of lithological objects in Kos’vinsky-Radaevsky, Bobrikovsky, and Tul’sky formations are created. Promising zoned of lithological objects associated with the deposits of onshore (subaerial) channels within fluvial distributary systems, subaqueous delta front fans, and bars are identified. According to interpretation of 2D seismic data and regional cubes, zones of search for new exploration targets associated with submarine extension of paleochannels and sandy fans to the marine part of sedimentary basin are delineated.

Key words: Volga-Urals Petroleum Province; pre-Urals Foredeep; Kamsky-Kinel’sky system of troughs; Tournaisian-Visean terrigenous formation; reservoir rocks; synthetic regional cubes; stratigraphic and combination traps.

For citation: Ermolova T.E., Mushin I.A., Stupak A.A., Frolov B.K., Oksman G.A., Kholmyanskaya N.Yu. Opportunities for new oil and gas bearing objects prospecting in the Upper Tournaisian-Visean terrigenous formations of eastern part of Volga-Urals Petroleum Province on the basis of integrated sedimentological and geoseismic studies. Geologiya nefti i gaza. 2019;(3):67-85. DOI: 10.31087/0016-7894-2019-3-67-85.

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