Molecular and carbon isotopic geochemistry of crude oils and extracts from Permian source rocks in the northwestern and central Junggar Basin, China

摘要

Highlights?76 oils are separated into two groups from individualn-alkane δ13C values.?Molecular parameters differ with some overlaps between the two oil groups.?Group I oils are mainly sourced from the Lower Permian Fengcheng Formation.?Group II oils are mainly derived from the Middle Permian Lower Wuerhe Formation.AbstractThe Junggar Basin is a major oil producing province in China. Most oil reservoirs found so far in this basin are in the Mahu sag and neighboring uplifts, northwestern Junggar Basin. A total of 78 oils and 10 Permian source rocks from the northwestern and central Junggar Basin and two oils and two Permian source rocks from the eastern Junggar Basin were analyzed by GC, GC–MS and GC–IRMS. The 78 oils can be clearly classified into two groups based on these analytical results. For group I oils, δ13C values of individua