Key words: hydrothermal fluids; epigenetic minerals; secondary porosity; zones of depression; seismic exploration; tectonophysics; Western Siberia; Cretaceous deposits.
For citation: Zubkov M.Yu. Tectonic and hydrothermal process in Cretaceous formations of the Western Siberia. Geologiya nefti i gaza. 2019;(1):7–26. DOI: 10.31087/0016-7894-2019-1-7-26.
The paper discusses epigenetic transformations of the West Siberian Cretaceous reservoir rocks under the influence of hydrothermal and tectonic processes. Transformations of both clastic part and cement are analysed in detail. Mechanism of secondary porosity formation caused by leaching with hydrothermal solutions of unstable minerals, which compose clastic and cementing parts of reservoir rocks, is reconstructed. Basing on the tectonic and physical modelling with the use of its two methods, mechanism
of decompaction zone formation is studied; reservoir rocks within this zone have higher porosity and permeability. Causes of tectonic and hydrothermal processes development in the basement rocks and sedimentary cover of the West Siberian basin including the Cretaceous rocks are summarized. Role of tectonic and hydrothermal processes in hydrocarbon formation, expulsion and migration towards reservoir rocks and formation of oil pools and fields is discussed. We propose an unusual way to predict zones of increased productivity in reservoir rocks using seismic data together with tectonic and physical modelling.