I.A. Marakova, O.M. Veltistova, E.N. Motryuk, M.Yu. Sabelnikov
Domanik-Tournaisian carbonate sequence in Verkhnepechorsky depression of Urals Foredeep: geodynamic aspects of oil and gas promising structural form occurrence
Key words: Urals Foredeep; Verkhnepechorsky depression; tectonodynamic factors; catagenesis; reef; magnetic field; gravity field; geodensity model.
For citation: Marakova I.A., Veltistova O.M., Motryuk E.N., Sabelnikov M.Yu. Domanik-Tournaisian carbonate sequence in Verkhnepechorsky depression of Urals Foredeep: geodynamic aspects of oil and gas promising structural form occurrence. Geologiya nefti i gaza. 2022;(6):5–18. DOI: 10.31087/0016-7894-2022-6-5-18. In Russ.
The paper discusses integrated studies of geodynamic factors influencing the occurrence of structural forms in the sedimentary cover, which can be seen in magnetic, gravity, and seismic fields. The initial information includes the location of Verkhnepechorsky depression, its tectonic framework, and boundaries. The purpose of the work was to reveal geodynamic aspects of oil and gas promising structural form occurrence within the Domanik-Tournaisian carbonate sequence of Verkhnepechorsky depression (Urals Foredeep). The authors use three criteria to substantiate oil and gas potential of the study area within the Verkhnepechorsky depression. Based on the analysis of geological and geophysical data, it was found that as a result of tectonic movements and at different dislocation degree of the depression, the inheritance of local structures from the topographical forms of crystalline basement becomes apparent. Proceeding from this, lithofacies zones were identified in the structural geometry of the Upper Devonian deposits, reflecting the sequence of individual barrier reefs, carbonate banks, and Domanikites formation. According to the results of geochemical data analysis, it was found that the majority of the Verkhnepechorsky depression is characterized by MK4–MK5 catagenesis stages. A general correlation of structural and tectonic forms of the studied Verkhnepechorsky depression with the geological basement surface, magnetic and gravity fields was carried out when working with geophysical materials. For a more detailed analysis, geodensity modelling was conducted applying the methodology of building density models for structurally complicated and underexplored formations with the use of PlayGround, EvDynInversion, GeoVip, and Surfer software products. Three geodensity models were created showing architecture of lithofacies zones and position of the expected objects depending on block tectonics. In conclusion, the authors analyse the results obtained in the studies and present their conclusions.