This study investigates the hydrocarbon generation and retention potential of Chang 7 organic-rich shale, with an emphasis on the producibility of retained hydrocarbons, using a sample set chosen to represent a maturity spectrum of 0.54 % to 0.9 % Ro and organic matter of type II and mixed type II-III. Based on the present-day hydrogen index (HIpd), the sample sets are divided into three sections, Upper, Middle, and Lower. The three sections have a high hydrocarbons generation potential, with an average original TOC (TOCo) of 12.27, 3.10, and 5.13 wt.% of which 49.39, 23.62, and 49.86 wt.% represent generative organic carbon (GOC), an original hydrogen index (HIo) of 581.27, 278.05 and 586.82 HC/g rock, in the Upper, Middle, and Lower Sections, respectively. The bulk of analyzed samples exhibit moderate-high oil saturation, yet the oil crossover effect is observed only in two organic-rich samples indicating organic-rich shale-oil resource systems. The sorption capacity of organic matter controls oil retention in the Chang 7 shale system, where the oil saturation index increases with increasing maturity in the oil window until a maximum retention capacity of about 82-83 mg HC/g TOC is reached at a vitrinite reflectance of 0.8% and thereafter decreases with further maturity.

Supplementary material: [Detailed spreadsheet of the back-calculated original geochemical parameters using the mass-balance method of Jarvie (2012a)], are available at https://doi.org/10.6084/m9.figshare.c.6387577.

This content is PDF only. Please click on the PDF icon to access.
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.