Turpan-hami Basin Coal-bearing Strata Of The Jurassic Source Rocks And Oil Biomarker Characteristics Of Coal-derived Hydrocarbon Significance

Geochemical study on coal-derived oils is still an active research area in China in the 21 century. From the viewpoint of geochemistry, there are still some important questions need to be further studied, such as it remains contentious about coal and coal measure mudstone which one is main contributor for the hydrocarbon generation. In the primary migration of coal-derived oils, the composition of hydrocarbon will be changed, a large amount of soluble heavy component generally stay in source rock, while light component enter reservoir and form light oil and/or condensates, all these will affect oil source correlation. In addition, resinate and vitrinite which one is major contributor for coal-derived oil, and history of reservoir and basic condition of reservoir are also important control factor for coal-formed oil.Coal, carbonaceous mudstone and oils from the Lower Jurassic coal measures in the Turpan basin have been studied in this paper, and biomarker characteristics and coal thermal maturity analyzed, allow us to draw the following conclusions:There are many similar biomarker characteristics between oil from middl-lower Jurassic of Turpan Basin and coal and carbonaceous mudstone in the same strata .they all contain specific r-lupane, I-norbietane,C24-tetracyclic terpane,cadalend retene,aromatic acides and high content of C29-steranes . These characteristics suggest that they have similar matter source of the organic matter are derived from matter with abundant high plants.Meanwhile,Biomarkers often used to indicate depositional environments is characterized by high Pr/Ph ratio,little or no gammacerane and high abundance dibenzofuranSjSuch biomarker distributions are indicative of suboxic and freshwater environment.IIAbstractAlthough coal and carbonaceous mudstone remain in lower thermal maturity (Ro=0.47~0.53), but C29- P P / ( a + P P )sterane ratio (0.294-0.489) and bezohopane are detected in our this study. Because these ferture are related to bacterial activity, so bacterial degrdation of organic matter maybe take an important role in coal-derived oil.Organic acid compounds studies shows that the aromatic acides are degradation matter of humic acid,so it is the characteristic biomarker which can be used to reflect high plants input.