鄂尔多斯盆地吴起地区长9段和长10段原油地球化学特征对比

发布时间：2018-09-03 17:16

【摘要】：鄂尔多斯盆地吴起地区延长组长9油层组和长10油层组的源储特征存在较大争议。针对这一问题,通过地球化学测定方法,对该地区长9段原油和长10段原油的地球化学特征进行了精细对比和解剖,研究发现:长9段原油地球化学特征变化较大,其正构烷烃具有双峰和单峰2种类型,C_(27)—C_(29)甾烷呈倒"L"型分布,表现出明显的高等植物输入特征,说明母质来源广泛。长10段原油正构烷烃呈单峰分布,C_(27)—C_(29)甾烷呈"V"型分布,母质来源基本上均为水生微生物,并且来源集中。结合碳同位素特征判断长9段—长10段原油形成于淡水弱还原—弱氧化环境中。综合以上特征推断出长9段原油和长10段原油可来源于不同的烃源岩。它们具有完全不同、相对独立的油源。长9段原油部分来自长7段上部烃源岩。该发现将为延长组下组合的成藏机理研究提供帮助。
[Abstract]:The source and storage characteristics of Yanchang 9 and Chang 10 reservoirs in Wuqi area, Ordos Basin are controversial. In order to solve this problem, the geochemical characteristics of Chang9 crude oil and Chang10 crude oil in this area are compared and dissected by geochemical method. It is found that the geochemical characteristics of Chang9 crude oil vary greatly. The n-alkanes have bimodal and unimodal C _ (27) C _ (29) steranes with inverted "L" distribution, showing obvious higher plant input characteristics, indicating that the parent material is from a wide range of sources. The n-alkanes of Chang 10 crude oil are distributed as a single peak distribution of C _ (27) C _ (29) steranes, and the source material is basically aquatic microorganism, and the source is concentrated in the source of C _ (27) C _ (29) sterane. According to the characteristics of carbon isotope, the crude oil of Chang 9 ~ Chang 10 is formed in the environment of weak reduction and weak oxidation in fresh water. Combined with the above characteristics, it is inferred that Chang9 and Chang10 crude oils can be derived from different hydrocarbon source rocks. They have completely different, relatively independent sources of oil. Part of Chang9 crude oil comes from the upper source rock of Chang7 formation. The findings will be helpful for the study of the accumulation mechanism of the Yanchang group.
【作者单位】：甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室;中国科学院大学;中国石油长庆油田分公司勘探开发研究院;
【基金】：国家科技重大专项“大型油气田及煤层气开发”(编号:2016ZX05007-004)资助
【分类号】：P618.13

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