Arctic Alaska Petroleum Systems: Characterizing Mixtures and Charge History Using Advanced Geochemical Technologies

Summary The Arctic Alaska petroleum province is geologically and geochemically complex. Mixed hydrocarbon charge from multiple source rocks and/or levels of thermal maturity is common within an individual oil pool. Molecular fingerprinting tools are used in the present study to characterize and establish genetic relationships among a suite of oils sampled from multiple discoveries and fields across the North Slope. Applications of Advanced Geochemical Technologies (AGTs) are utilized to identify and correlate fluids generated from deep sources, determine co-sources for oil mixtures, and ascertain controls on hydrocarbon provenance ( Dahl et al., 1999 ; Moldowan et al., 2015 ). The AGTs presented here comprise quantitative diamondoid analysis (QDA), quantitative extended diamondoid analysis (QEDA), compound specific isotope analysis of diamondoids (CSIA-D), biomarker assessments by gas chromatography-tandem mass spectrometry (GC-MS-MS), CSIA of hopane and sterane biomarkers (CSIA-Bh and CSIA-Bs, respectively), and CSIA of n-alkanes (CSIA-Ac). Diamondoid analyses reveal mixed-oil accumulations in most sampled reservoirs and allow the source(s) of both post-mature and oil-window maturity charge contributions to be identified. Age-diagnostic and source-sensitive biomarker parameters provide an assessment of age ranges and depositional environmental constraints of the sources of the oil-window components. Results of CSIA-Bh, -Bs, and -Ac provide greater insight into paleoenvironments of the generative sources.