民和盆地原油地球化学特征与油源对比

民和盆地是一个油、煤、气共生的盆地,其原油属中等密度、低粘度、低硫高蜡较轻质油,具饱和烃含量高(占原油的60%~80%)和C27甾烷含量低、C29甾烷含量高等特点。指出中侏罗统窑街组的暗色泥岩、油页岩、碳质泥岩及煤为主要烃源岩,上侏罗统享堂组及下白垩统河口组砂岩为主要储集岩。通过饱和烃气相色谱、甾烷、霍烷、生物标记化合物等的对比表明,民和盆地原油与中侏罗统窑街组的暗色泥岩和油页岩有较明显的亲缘关系,因此认为民和盆地的原油主要来自中侏罗统窑街组的暗色泥岩和油页岩。

GEOCHEMICAL CHARACTERISTICS OF CRUDE OIL AND CORRELATION OF OIL-SOURCE IN MINHE BASIN

Minhe basin is a special type basin with oil,coal and natural gas.The crude oil are characterized by mid-density,lower viscosity,lower sulphur,higher wax,higher content of saturated hydrocarbon,lower C_(27),higher C_(29) sterane.The dark mudstone,oil shale,black mudstone and coal in Yaojie formation of middle Jurassic are the major hydrocarbon source rocks.Xiangtang formation of upper Jurassic and Hekou formation of lower Cretaceous are the major reservoir rocks.The correlation from gas-chromatography of saturated hydrocarbon,sterane,hopane,biomarker of oil-source shows that the crude oil and the dark mudstone, oil-shale in Yaojie formation of middle Jurassic are correlated.The crude oils of Minhe basin are mainly from dark mudstone and oil-shale in Yaojie formation of middle Jurassic.