Hydrogeochemistry of the Arctic areas of Siberian petroleum basins

Abstract

Abstract: The available hydrogeochemical data collected over the past four decades in Siberian Arctic areas were analyzed and interpreted comprehensively for the first time, through data ranking, evaluation and analysis, systematic estimation of region, altitude background and abnormal value, and calculation of element molar ratio, different kinds of correlation coefficients in water proximity were estimated. Paleohygdrogeological reconstructions of the Siberian sedimentary basins suggest the presence of three water genetic types in petroleum deposits: (1) Waters that formed during marine sedimentation, (2) Waters of meteoric origin that infiltrated the basin and were involved in supergene processes in the geological past, (3) Waters produced by condensation from a hydrocarbon mixture. Hydrogeochemical patterns of petroleum deposits are controlled by the long geological evolution in the water-rock-gas-organic matter system. Sodium-chloride bicarbonate, sodium chloride, calcium chloride groundwaters, and other types of brines with the total salinity of 0.2-350 g/L are distributed in the Siberian Arctic sedimentary basins. Comparative analysis of groundwaters and brines in the Siberian Arctic revealed a group of sodium chloride water samples had a total salinity of over 250 g/L, suggesting the formation of the brine was related to leaching of evaporite rock. Hydrogeochemical data indicate that composition of the brine has varied dramatically with their evolution. Mesozoic groundwaters and brines of Anabar-Laptev basin and West Siberia existed only in the beginning of their chemical evolution. Key words: Arctic, Siberia, petroliferous basins, hydrogeology, aquifer, hydrogeochemical patterns, groundwater evolution