Rhenium-osmium geochronology in dating petroleum systems:progress and challenges

Abstract

Re and Os are redox-sensitive and organophilic, and can be enriched in potential hydrocarbon source rocks, tar sands, crude oil, and bitumen. Re-Os geochronology of these organic-rich samples has the potential for direct dating the time frame of hydrocarbon formation, migration or charge within a petroleum system. Moreover, the initial 187Os/188Os composition can also be used to fingerprint oil-oil and oil-source rock correlations. Here, we review some major reported case studies on the Re-Os geochronology of oil and gas reservoirs over the last decade. Through evaluating the advancements and shortcomings in Re-Os geochronology for petroleum system analysis, and considering the actual requirement of hydrocarbon exploration, we conclude that it is quite urgent to investigate the detailed behavior and fractionation mechanisms of Re and Os in a petroleum system, to evaluate the influence of TSR (thermochemical sulphate reduction) and thermal cracking on the Re-Os isotopes in hydrocarbons, and to establish a more reliable and efficient inorganic-organic geochemical tool allowing effectively fingerprint the fate of petroleum from its source to trap, and for oil-oil correlations. Filling the above knowledge gaps requires a comprehensive academia-industry collaboration, which is critical step to accomplish a valuable application guide for the petroleum industry end-users on using the Re-Os isotope system to directly date petroleum systems.