PETROLEUM POTENTIAL OF EAST SIBERIA

The East Siberian craton covers an area in excess of 3.8 million sq. km. A rapid, pragmatic approach to focus attention and resources on the most hydrocarbon-prospective areas without compromising the study quality has been developed.

Principal building blocks for prospectivity assessment in chronological order of appearance were tectono-stratigraphic diagrams consistent with tectonic evolution of margins of the East Siberian craton. These constrained the basins developed on the margins of the East Siberia craton from Pre-Cambrian to Tertiary times. Relevant paleogeographic maps representing gross depositional environments at certain time slices were constructed with special attention to major reservoir and source rock depositional events. Levels with reservoir presence were further analysed for reservoir effectiveness at different depths. Oils and source rock geochemical data were input into the geological framework to characterize the range of petroleum systems. The very long geologic evolution of East Siberia resulted in a wide variety of source rocks spanning from Pre-Cambrian to Cretaceous in age, most of which generated significant volumes of hydrocarbons.

The tectono-stratigraphy, gross depositional environment maps, and petroleum systems were the technical building blocks for a series of common risk segment (CRS) maps, which were drawn for petroleum charge, reservoir, and trap regional risks, which in turn provided a stratigraphic and geographic focus of which basins had most potential for further exploration. Commercial considerations were further addressed by considering minimum petroleum volumes and reservoir performance required reflecting the remoteness of East Siberia and absence of significant infrastructure. Based on this approach, a basin and play ranking for East Siberia exploration has been developed.