Source Rock Evaluation for Shublik Formation, Kingak Shale, Pebble Shale, and GRZ in the North Slope of Alaska

Abstract

The North Slope of Alaska is a prolific oil and gas province partly caused by multiple effective source rock units. In this research, four source rock units were identified including Triassic Shublik Formation, Jurassic Kingak Shale, Cretaceous Pebble Shale, and Cretaceous GRZ. We reviewed source rock geochemical interpretations from previous North Slope studies and assessed source rocks quality, maturity, and organic facies focusing on the Central of North Slope to the East of National Petroleum Reserve Alaska (NPRA). Our dataset includes 470 samples with TOC and Rock-Eval measurements, as well as vitrinite reflectance and biomarker data. The TOC ranges for Shublik Formation, Kingak Shale, Pebble Shale, and GRZ are 0.8-6.9, 0.9-20.5, 1.2-3.5 and 1.1-10.4 wt%, respectively. Based on Rock-Eval pyrolysis and vitrinite reflectance data, these source rocks are immature and early mature. However, geochemical evaluation indicates that the Kingak Shale is the most favorable source rock with oil-prone kerogen type I. The other source rock units (Shublik Formation, Pebble Shale, and GRZ) tend to have kerogen type II – III. Biomarker analyses of four source rock units suggest that marine shale source organofacies (Class B) dominate in this area.

AAPG Datapages/Search and Discovery Article #90372 © 2020 AAPG Pacific Section Convention, 2020 Vision: Producing the Future, Mandalay Beach, Oxnard, CA, April 4-8, 2020 (Cancelled)