【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,C₂₇—C₂₉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,C₂₇—C₂₉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。更多还原

【Abstract】 There are great disputes about the source and reservoir characteristics of Chang 9 oil-bearing formation and Chang 10 oil-bearing formation in Yanchang Formation,Ordos Basin.Aiming at this problem,the geochemical characteristics of crude oil in Chang 9 reservoirs and Chang 10 reservoirs were finely contrasted and dissected.The study showed that geochemical characteristics of crude oil in Chang 9 reservoir ranged obviously.The distribution of n-alkanes resented two types:Single-peak or double-peak carve;The structure of the sterane is reversed "L"type distribution,which showed obvious characteristics of higher plant input,indicating a wide range of parent material;The distribution of n-alkanes in Chang 10 reservoir showed single-peak distribution.The structure of the sterane is"V"type distribution,showing the sources of parent material were mainly aquatic microorganisms,and the sources were relatively concentrated.Combined with carbon isotope characteristics,it can be judged that the Chang 9-Chang 10 crude oils were formed in the weak reductive weak oxidation environment with fresh water.Based on the above characteristics,it is concluded that the crude oil of Chang 9 and Chang 10 can be derived from different source rocks.They have completely different and relatively independent source reservoir characteristics.Chang 9 crude oil was partly sourced from the upper part of Chang 7 source rock,which will be helpful to the study of reservoir forming mechanism in the lower Yanchang Formation.更多还原