Molecular and Isotopic Geochemistry: Technology Development and Applications to Exploration From the Present-Day to Mid-Century

Abstract

As essential and cost‐effective tools, molecular and isotopic geochemistry have largely been applied to petroleum exploration since the late 1970s. Consequently, molecular and isotopic technology development boomed between the 1980s and 2000s. Many novel age‐, depositional environment‐, lithology‐, source facies‐, and maturity‐related biomarkers had been identified in that period by our pioneering petroleum geochemists. Diamondoids were identified and utilized to estimate maturity and extent of oil‐to‐gas cracking. C7 parameters were developed for understanding source origin, maturity, correlation, and alteration. Stable isotopic compositions of key elements (C, H, N, O, S) in kerogen, especially carbon and hydrogen, were also used to evaluate source origin, maturity, correlation, and alteration. When source rocks were not penetrated, molecular and isotope geochemistry together could help infer the source rock and its characteristics (e.g., age, lithology, kerogen type, maturity). These inferences, in turn, assist petroleum system analysis and provide the opportunity for more accurate migration modeling and fluid property prediction. As peak generation geochemists, we are very lucky to have been supervised by our world‐class petroleum geochemists. Now, it is our responsibility to pass the torch to the next generation. This presentation will review current state‐of‐the‐art biomarker/diamondoids/light hydrocarbon and stable isotope technology developments and their applications to exploration, including new biomarker identification (e.g., Carotenoid biomarkers), new diamondoids applications (e.g., Quantitative Extended Diamondoids Analysis), CSIA (Compound Specific Isotope Analysis) of biomarkers/diamondoids, CSIA of sulfur isotopes of sulfur compounds, and new analytical techniques (e.g., Triple Quadrupole (QQQ) GCMSMS, GCGC‐TOFMS, GCGC‐FID). It will also help envision what petroleum geochemistry will look like in the next 20 to 30 years. The first thing to consider is whether in the next 20 to 30 years petroleum exploration will still occur, since renewable energy sources are taking over to provide part of the energy supply. Assuming there is still a significant need for exploration, we will largely focus on light fluids and gas from unconventional plays. As we know, saturated biomarkers in light fluids are below the detection limits by current analytical techniques. Therefore, we should work with analytical chemists and engineers to develop instruments capable of much greater selectivity and sensitivity. For age‐related biomarkers, we should engage in research to develop higher age resolution parameters, e.g., to separate Upper vs. Lower Cretaceous, Upper vs. Lower Jurassic, and Permian vs. Devonian ages. This endeavor will require collaboration between geochemists, paleontologists, and analytical chemists. Geochemical analysis often produces large datasets. Can we identify new biomarkers and new applications by big data analysis of geochemical data and integration with other disciplinary data? The final topic for this presentation will be how we should work together to pass the torch to the younger generation and how we can carry forward our technologies to provide a greater business impact. As well‐trained geochemists, we should continue to improve our knowledge, to develop new techniques and to create new business values by collaborating with our seasoned geochemists. At the same time, we should motivate younger generation’s interest through mentorship, and advocate business values of geochemistry at exploration and production.

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