Diamondoids: Their Potential to Modernize Basin Analysis and Reshape the Future of Basin Modeling
Petroleum exploration is all about creating prospects that can yield new discoveries. While classical geochemical technologies such as isotopes of oils and oil fractions and biomarkers are extremely useful, they have already been applied to most of the basins in the world and therefore, are unlikely to yield many new exploration ideas. New geochemical techniques can provide crucial information that was previously unobtainable. Quantitative diamondoid analysis (QDA) is used for determining the maturity of any oil sample in both conventional and unconventional applications. The high degree of accuracy needed for application of this method is achieved by spiking the liquids with deuterated diamondoids before GCMS analysis. More recently, the ability to perform source correlations by using diamondoids has been developed. These correlation methods have an advantage over all others due to the thermal stability and recalcitrancy of diamondoids toward biodegradation. Thereby, all bitumen and oil samples (condensate, biodegraded oil, black oil) can be correlated by diamondoids. One method (called QEDA) is based on quantitative analysis of large diamondoid molecules ranging from tetramantanes to pentamantanes to cyclohexamantane, which occur in several isomeric structures that can be displayed in a similar fashion to biomarker fingerprints. A second approach (CSIA‐D) is to measure the diamondoid C‐isotope ratios. The structural diversity and isotopic ratios of diamondoids are set in the source rock making them viable for correlation. The generative formations and the migration paths for hydrocarbons are critical root determinates for developing basin models. However, source components are often missed when only the typical biomarker and isotope methods are applied. Because diamondoid methods are useful to correlate all types of fluids, they can succeed when biomarkers are ineffective or absent. In mature basin shallow charging source rocks with an abundance of biomarkers are easily characterized. However, deep sources with low or negligent biomarker concentrations often completely elude detection, especially when oil is co‐sourced and overprinted by oil from a shallow biomarker‐rich source.
AAPG Datapages/Search and Discovery Article #90349 © 2019 AAPG Hedberg Conference, The Evolution of Petroleum Systems Analysis: Changing of the Guard from Late Mature Experts to Peak Generating Staff, Houston, Texas, March 4-6, 2019