Furthermore, as Re and Os have been inherited from the source rocks, Os isotopes can be employed to correlate an oil with its source.
Re - Os dating and oil - source rock correlation is actually helped if the oils are highly biodegraded, e.g., oil sands, tar mats and bitumen-stained sandstones (where traditional techniques such as biomarker identification are disrupted), as this concentrates Re and Os within an oil making analysis easier.
In this regard, the Re–Os system to study the geochemical evolution of mantle rocks and in defining the chronology of mantle differentiation is extremely helpful.
The information presented below briefly outlines how Chemostrat is utilising two of these techniques, i.e., the Rhenium - Osmium (Re - Os) isotopic dating technique and the Uranium - Lead (U - Pb) isotopic dating technique, to assist the petroleum industry in the goals of oil and gas exploration.
Re and Os become concentrated in the organic, hydrogenous fraction of organic rich shales, thus the time when the shale was deposited can be dated.
The Os value calculated at the time of deposition (Osi) can also provide information on whether deposition occurred in a lacustrine or an open marine environment.
When oil is formed from a source rock, a proportion of the Re and Os from the source rock is transferred to the oil, thus one can date the formation process using the Re - Os geochronometer.