吐哈盆地侏罗系煤系地层源岩和油的生标特征及其煤成烃意义

【作者】 房嬛；

【导师】 孟仟祥；

【作者基本信息】 中国科学院研究生院（兰州地质研究所） ， 地球化学， 2004， 硕士

【摘要】 21世纪我国煤成油地球化学研究，仍然是一个活跃的研究领域。从学科的角度，煤成油的研究也有一些重要问题有待深化，如煤成油初次运移中分异作用非常强烈，重质可溶组分大量滞留在源岩中而聚集到煤成油藏中的几乎都是凝析油或轻质油，这就带来油源对比上的困难。还有基质镜质体和树脂体等成烃之争，以及煤成油藏的成藏史及其成藏的基本条件等，都是一些值得进一步研究的问题。 本文通过对吐哈盆地煤系地层中下侏罗统煤岩、碳质泥岩、原油进行了饱和烃、芳烃、尤其是有机酸的研究工作。探讨其生物标志化合物特征与煤岩演化特征之间的辩证关系。获得以下认识： 一、吐哈盆地侏罗系原油与中下侏罗统煤系地层煤岩及碳质泥有亲缘关系。证据如下： A．具有共同的特征生物标志化合物：γ—羽扇烷、异降松香烷、C₂₄一四环二萜烷、高丰度C₂₉甾烷、卡达烯、惹烯、苯并蒽、苯并藿烷、芳香酸等。表明它们具有相同的高等植物母质来源。 B．较高Pr／Ph比值、三芴中的氧芴优势以及γ-蜡烷相对丰度很低等指示环境的参数具有一致性。说明它们的早期沉积环境相同，都是水质偏淡的弱氧化、弱还原环境。 二、甾烷异构化参数C₂₉—ββ／（ββ+αα）在研究的低演化煤岩及碳质泥岩（R_o：0.47～0.53）中显示明显的高比值（0.294—0.489），以及煤岩、碳质泥岩、原油样品中苯并藿烷的检出，表明吐哈盆地中下侏罗统煤系地层古环境中细菌微生物比较发育，细菌微生物作用导致煤岩和碳质泥岩在成岩早期的生烃和排烃现象，细菌微生物的自身降解作用也为煤成烃作出贡献。 三、在对样品有机酸的研究过程中，检测出丰富的有机芳香酸系列化合物，它是腐植酸的降解产物，为高等植物母质来源的特征生物标志化合物。更多还原

【Abstract】 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.更多还原