川东南地区官9井侏罗系原油地球化学特征

GEOCHEMICAL FEATURES OF CRUDE OIL FROM JURASSIC WELL GUAN-9 IN SOUTHEAST SICHUAN BASIN

2004年钻探的官9井首次在川东南地区的中侏罗统下沙溪庙组获得工业性轻质油流。该原油含蜡量高,姥姣烷/植烷比值较低(Pr/Ph=1.56),族组成中饱和烃含量在90%以上,原油轻烃的正庚烷与甲基环己烷的比值高达1.83,并且庚烷值和异庚烷值具有高成熟湖相原油的特点。根据原油饱和烃与轻烃气相色谱以及碳同位素等资料,综合分析结果认为:官9井侏罗系原油为高成熟腐泥型母质成因,主要来源于侏罗系湖相烃源岩。

The well Guan-9, an exploratory well drilled in 2004, has obtained industrial oil flow with light hydrocarbons in the low Shaximiao formation of Jurassic in Southeast Sichuan Basin. The crude oil samples from this well have high paraffin content, rather low ratio of Pr/Ph (only 1.56). The content of saturated hydrocarbons accounts for above 90%, the ratio between n heptane and methylcyclohexane in light hydrocarbons is as high as 1.83, and the haptane and iso-haptane values of the oil shows some traits of hyper-matured lacustrine crude oil. According to various data of carbon isotope and GC NMRS of saturated hydrocarbons and light hydrocarbons in crude oil, this study concluded that the oil drilled from the well Guan-9 was originated from higher maturity sapropelic organism, and mainly migrated from the lake faces hydrocarbons source rock.