Features of composition of oil extracts from the rocks of basement and sedimentary stratums of the Novo-Elkhovskoye field of Tatarstan

Abstract

© 2019, © 2019 Taylor & Francis Group, LLC. A comparative analysis of oil extracts from the rocks of the crystalline basement of the ultra-deep well 20009 of the Novo-Elkhovskoye field located within the South-Tatar Arch of the territory of Tatarstan, as well as from the sedimentary strata of the Devonian productive deposits of the Aktashskaya area of this field was carried out. A different yield of extracts from fault rocks (0.018%) and low-permeable (0.007%) basement zones was established and differences in their group and structural-group composition were revealed. In the fault zones of the basement rocks, in comparison with the rocks of low-permeable intervals, resin-asphaltene components predominate, indicating the occurrence of more intense hypergene processes in them. The data of component, structural-group composition and geochemical characteristics of extracts from basement and sedimentary rocks indicates their genetic relationship with sapropel organic matter (OM) of marine genesis. This confirms the fact that the fault and low-permeable zones of the basement rocks served as migration routes for petroleum hydrocarbons during the formation of oil-bearing fields in the South-Tatar Arch.