Re-Os Geochronology and Tracer Studies for Petroleum Exploration -- Starting Materials to Construction of Whole Petroleum Systems

Abstract

Re-Os isotope geochemistry is now a sure but still very new technology for tracking the construction of petroleum systems in real time. We have achieved this by weaving work performed on natural petroleum systems (ground-truth), with experimental work addressing metal behavior during oil-water interaction. For reconstruction of natural systems, we have worked closely with industry to acquire cores carrying residual early oil charges, transition zones leading to fully developed tar mats, second light oil charges both in situ as an oil leg, and oil drawn from wells. We organize these events in real time with Re-Os radiometric ages. We use the Os isotope tracer to determine the relationships between source rocks and different oil charges, and the mixing of oils and water-oil. We are now working with sulfides and oils occurring together in reservoir rocks to understand clearly visible relationships between oils, metals and sulfur.

In the last two years, Re-Os technology coupled with smart sampling and geologic understanding has revolutionized our knowledge of how oil is put together, and how metals are involved. We work with both the asphaltene and maltene components of oils. We have taken oils apart to test preservation of radiometric ages in polar and non-polar fractions. All of these pieces of the petroleum puzzle are tied to geologic relationships. As expected, different petroleum systems have different assembly lines, but an overarching conclusion of our work is that rifted-margin environments are recipients of deep, basin-external fluids that may be an important instigator in kicking kerogen toward maturation and expulsion. In this presentation, the steps leading to ground-breaking conclusions using Re-Os isotope geochemistry applied to petroleum systems will be presented in a context for all those working in the petroleum industry to understand, and to appreciate the value in this emerging and exciting new technology.

Support of Research and Technology Development - Aker BP, ENI, Lundin, Equinor

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AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019