Source identification and accumulation restoration of complex oil reservoirs in Mahu Sag, Junggar Basin

作者：Dongming Zhi, Wendong Liu, Wenxuan Hu, Jian Cao, Menglin Zheng, Tao Wang · 发表于：Energy Exploration & Exploitation · 年份：2023 · DOI：10.1177/01445987231191797 · 被引用次数：7 · 研究领域：Hydrocarbon exploration and reservoir analysis、Petroleum Processing and Analysis、Geochemistry and Geologic Mapping

Oil sources and accumulations in complex oil reservoirs of superimposed basins are difficult to identify and recover because of multiple kitchens and multistage charging processes. Constraining the oil sources and characterizing their accumulation patterns is a critical challenge. In this study, 46 crude oils from the Upper Wuerhe Formation, a widely distributed oil reservoir in the Mahu Sag of the Junggar Basin, NW China, are geochemically characterized to assess their sources and spatial distribution. These oils are divided into four groups: group I oils (characterized by high β-carotane and gammacerane concentrations, low C 21 /C 23 and (C 19 + C 20 )/C 23 tricyclic terpane ratios, and low Pr/Ph ratios); group II oils (characterized by low β-carotane and gammacerane concentrations, high C 21 /C 23 and (C 19 + C 20 )/C 23 tricyclic terpane ratios, and moderate Pr/Ph ratios); group III oils (very high Pr/Ph ratio (>3), the lowest β-carotane and gammacerane concentrations, and low tricyclic terpane concentration, but relatively high C 19 and C 20 tricyclic terpane abundance); and group IV oils (refered to here as geochemically hybrid, and inferred to be sourced from mixed P 1 f and C/P 1 j source rocks). The integration of oil-source correlation and geological framework indicates that oils generated from multiple kitchens are more likely to be near-sourced accumulations, providing a plausible example for oil accumulation in a complex oil reservoir of superimposed basin wit...