Home – Home – Jornals – Geography and natural resources 2016 number 6S

The main oil and gas promising resources of the southern Siberian platform are related to subsalt terrigenous rocks of the Riphean and Vendian-Lower Cambrian age occurring in the lower sedimentary cover, as well as the Cambrian carbonate ho rizons of subsalt and overlying carbonate-halogen complexes. The specific geological framework of the sedimentary cover of the southern Siberian platform is associated with intermittent nature of reservoir distribution and lack of anticlinal structural forms. This causes particular localization of oil and gas accu mulations, and influences the effectiveness of standard geological and geophysical methods used in their exploration. Petrophysical analyses results show that reservoir properties of rocks are most clearly reflected in their electrical resistivity. This provides an objective basis for widespread applications of electromagnetic methods in oil and gas exploration, the near-field transient electromagnetic sounding (NTES) in particular. Modern methods of electromagnetic sounding data interpretation allow estimating conductivity of the geologic intervals containing productive horizons with an accuracy of a few tens of percent. Using resistivity of formation water and available data on the relationships between volume porosity and porosity factor allows estimating capacity of water-saturated reservoir voids by their conductivity. Given the data on average value of the re sidual water saturation factor and average HC-saturated-to-water-saturated reservoir ratio, we can estimate hydrocarbon re sources on a regional scale. The proposed method for reservoir voids calculation by their geoelectric properties can be used as the basis for appraisal of C3 hydrocarbon reserves.