Rock-Eval/TOC analysis of selected core intervals from the Beaufort-Mackenzie Basin, northern Canada -- their source rock potential

Abstract

A total of 134 samples collected from the dark-colored intervals of cores taken from oil and gas exploration wells in the Beaufort-Mackenzie Basin were analyzed using Rock-Eval/TOC technique. The aim of the project was to determine the petroleum source rock potential of selected Tertiary, Cretaceous and Jurassic intervals based on their organic richness, type of organic matter and their thermal maturity. This Rock-Eval reconnaissance will provide guidance for further oil-source correlation studies to better understand the petroleum systems in the Beaufort-Mackenzie Basin. Well cores were selected based on core description by Dixon (2002) and visual observation of the cores. Care has been taken to avoid intervals with possible drilling mud contamination. Rock-Eval analytical results indicate that the Tertiary mudstone and coal measures contain immature to marginally mature Type III organic matter. TOC content of the Tertiary mudstone and shale sections can be as high as 5%. Its hydrocarbon potential is apparently lower than that of the Cretaceous and Jurassic rocks that appear to contain both Type III and Type II organic matter at similar or higher content. Thermal maturity of the Cretaceous and Jurassic potential source rocks ranges from marginally mature to over-mature, depending on their location in the basin. These results indicate that the Cretaceous and Jurassic source rocks have made significant contribution to oil and gas accumulations in the Beaufort-Mackenzie Basin.