全烃地球化学细分狮子沟构造油气源

Hydrocarbon source scrutinized by total hydrocarbon geochemistry for Shizigou structure in western Qaidam Basin

为确认狮子沟构造油气来源,对研究区域内天然气组成、油气碳同位素、油轻烃和生物标志化合物进行研究,确认了狮子沟构造油气的全烃地球化学特征,细分了不同油气的成因和来源。研究表明,狮子沟构造油气主要来自下第三系烃源岩,并多以湖相腐泥或混合型成因为主。深层E32和E31油气多具有自生自储的特征,浅层油气属于E32和E31成因烃类的混合叠加而成,但多表现为以E32来源为主、E31来源为辅的特征,并且充注部位不同,其中E31成因油气注入区分布在构造高部位,而E32成因油气注入区分布于构造翼部。

The geochemical characteristics of total hydrocarbon in Shizigou structure,Qaidam Basin have been determined through studying natural gas component,carbon isotope,light hydrocarbon,and biomarker to scrutinize the genesis and sources of different oil and gas.The study shows that the oil and gas in Shizigou structure mainly came from Eogene source rock which was mainly comprised of lacustrine sapropel or of hybrid genesis.The oil and gas in deep E32 and E31 formation are characterized by self-generating and self-reservoiring.The shallow oil and gas are a mixture of E32 and E31 hydrocarbon,but mostly present to be of E32 origin,supplemented with E31 origin.The locations of oil and gas charge were also different.The oil and gas of E31 origin had charged structural high,while the oil and gas of E32 origin had charged structure flank.