Impact of Reservoir Heterogeneity on Bitumen Content in the Mackay River Oil Sands, Athabasca (Canada)

• Published in: Acta geologica Sinica (Beijing) Vol. 98; no. 5; pp. 1285 - 1300
• Main Authors: YANG, Xiaofa, YU, Diyun, WU, Suwei, REN, Junhao, CHENG, Dingsheng, HUANG, Jixin, YANG, Chengyu, MA, Guoqing, LI, Meijun
• Format: Journal Article
• Language: English
• Published: Richmond Wiley Subscription Services, Inc 01.10.2024; Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China%China National Oil and Gas Exploration and Development Company,Beijing 100034,China%National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China
• Edition: English ed.
• Subjects: Anniversaries; Biodegradation; Bitumen; bitumen content; Bitumens; Canada; Cretaceous; Data logging; Degradation; geochemical characteristics; Geochemistry; Heterogeneity; Intervals; Lithofacies; Logging; Oil; Oil sands; Physical properties; reservoir heterogeneity; Reservoirs; Sand; Sand bars; Sedimentary facies; Sedimentary rocks; Sedimentology; Shale; Shales; Upper McMurray Formation; Canada; bitumen content; oil sands; reservoir heterogeneity; Upper McMurray Formation; geochemical characteristics
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/1755-6724.15123

The Lower Cretaceous Manville Group of Upper McMurray Formation is one of the main bitumen reservoirs in Athabasca. In this study, the relationship between reservoirs heterogeneity and bitumen geochemical characteristics were analyzed through core and microscopic observation, lab analysis, petrophysics and logging data. Based on the sedimentology framework, the formation environment of high‐quality oil sand reservoirs and their significance for development were discussed. The results indicate that four types lithofacies were recognized in the Upper McMurray Formation based on their depositional characteristics. Each lithofacies reservoirs has unique physical properties, and is subject to varying degrees of degradation, resulting in diversity of bitumen content and geochemical composition. The tidal bar (TB) or tidal channel (TC) facies reservoir have excellent physical properties, which are evaluated as gas or water intervals due to strong degradation. The reservoir of sand bar (SB) facies was evaluated as oil intervals, due to its poor physical properties and weak degradation. The reservoir of mixed flat (MF) facies is composed of sand intercalated with laminated shale, which is evaluated as poor oil intervals due to its poor connectivity. The shale content in oil sand reservoir is very important for the reservoir physical properties and bitumen degradation degree. In the context of regional biodegradation, oil sand reservoirs with good physical properties will suffer from strong degradation, while oil sand reservoirs with relatively poor physical properties are more conducive to the bitumen preservation.