Download PDF

SILURIAN REEF OF THE LEDYANSK UPLIFT AS A POTENTIAL RESERVOIR OF HYDROCARBONS IN THE NORTH OF THE SIBERIAN PLATFORM

I. V. Varaksina

А. А. Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia

The results of the lithological study of the Silurian sediments drilled in by wells within the Ledyansk uplift in the north of the Siberian platform are presented. It is found that in the early Silurian time on the territory under consideration a large organogenic buildup corresponding to typical Silurian reefs of a stable shelf was formed, the formation stage of its framework was confined to Wenlock. In Late Silurian, against the background of regression, the reef formations were overlain by lagoon-sebkha clayey-evaporite deposits. It is shown that the heterogeneity of the section affected the distribution of reservoir properties. The high primary porosity of the reef framework contributed to the processes of dissolution, stylolization, fracturing and formation of a high-capacity reservoir. The combination of various voids led to the development of a complex reservoir. The saline-sulfate rocks of the Upper Silurian – Lower Devonian act as a seal. The question of the prospects for the oil and gas potential of the Silurian reef deposits is of particular relevance in view of the wholesale development of organogenic buildups on the Siberian platform in the Wenlock time.

Keywords: Siberian platform, Silurian, reef, carbonate rocks, sedimentary environments, reservoir.

DOI 10.20403/2078-0575-2020-3-13-22