Organic geochemistry of Carboniferous source rocks and their generated oils from the Eastern Junggar Basin, NW China

The free, adsorbed and inclusion oils from three oil-containing volcanic reservoir rocks within the C2b formation generally correlate with C1d source rocks based on molecular and carbon isotopic data. However, the three types of oil from the same reservoir rock vary significantly in molecular and carbon isotopic compositions, reflecting facies and maturity changes of charging oil during the reservoir filling.