GEOCHEMISTRY OF OIL AND IDENTIFICATION OF SOURCE ROCKS IN THE DINAN ARCH-FUBEI SLOPE AREA OF JUNGGAR BASIN

The Dinan Arch and Fubei Slope are located in the east of the central uplift belt of the Junggar Basin. There are several hydrocarbon depressions and four kinds of source rocks, which make the oil-source rather complicated. In order to make correlation between the source rock and the oil, several geochemical indicators are used for subdivision of the oil into three categories. The A type of oil has light carbon isotope, phytane preponderance and high gammacerane, indicating a lacustrine origin with blood relation to the Permian source rock; the B type of oil has heavier carbon isotope, pristine preponderance and less gammacerane, suggesting that the proto kerogen was formed in a sedimentary environment of strong oxidation. The oil is believed coming from the Jurassic source rock; the C type of oil shows the features in between and is supposed to come from both the Permian and Jurassic source rocks.