Unravelling hydrocarbon charge history of the Shublik Formation, Central North Slope of Alaska
The Middle to Upper Triassic Shublik Formation is one of the key source rocks for hydrocarbons in Arctic Alaska and the greater Prudhoe Bay field area, the largest field in the North America. It is a laterally and vertically heterogeneous unit that has been described both in outcrop and in the subsurface, and interpreted to have been deposited under fluctuating oceanic upwelling conditions.
Graduate student Inessa Yurchenko in her work investigates source rock geochemistry, stratigraphic architecture, and unconventional shale resource potential in the context of petroleum system modeling. Project 1 examines four principal source rocks of the Central North Slope of Alaska, and provides a detailed core-based analysis in a frontier area south of the producing fields. It also gives insight into thermal history of the area via present-day source rock thermal maturity. Project 2 examines stratigraphic architecture of the Triassic Shublik Formation and provides insight into the ancient upwelling system. Project 3 incorporates findings of Projects 1 and 2 into a high-resolution petroleum system modeling study. Together, all chapters present a detailed shale resource system analysis, which will ultimately contribute to the growing body of knowledge in such exploration frontiers linking geochemistry, sedimentology, and basin and petroleum system modeling.
This research incorporates field observations, subsurface data interpretation, and laboratory work. Organic geochemical studies involve source rock screening methods, analyses of biomarkers and diamondoids, including quantitative diamondoid analysis (QDA), quantitative extended diamondoid analysis (QEDA), and compound specific isotope analysis of diamondoids (CSIA-D). Inorganic geochemical studies focus on chemostratigraphic analysis of Shublik cores using hand-held XRF data as elemental proxies for environment of deposition. Combining chemofacies with biomarker paleoredox proxies, lithological description of the cores, provides a highly-detailed, core-based understanding of the Shublik source rock properties distribution.
Fig. 1. Map of part of northern Alaska showing location of study area. Central North Slope is indicated in yellow. Main producing oil fields are in green, NPRA - National Petroleum Reserve in Alaska, ANWR - Arctic National Wildlife Refuge, TAPS - Trans-Alaska Pipeline System.
Fig. 2. Organic geochemical studies of North Slope oils (column chromatography).
Fig. 3. XRF studies of trace and major elements in cores.
Fig. 4. Last Creek Outcrop, North Slope of Alaska.
Fig. 5. Shublik Formation in outcrop.