东营凹陷沙三 、 沙四段石油运移地球化学特征及意义

摘 要　 利用生物标志化合物、 碳同位素和原油烷烃色谱等地球化学指标研究了东营凹陷沙三段(Es 3 )、 沙四段(Es 4 )油气运移的基本规律。 油源对比证实, 利津和牛庄洼陷 Es 3 、 Es 4 生油岩分别向其附近和周缘地区提供了油源。 根据 “ 地质色层” 原理, 分析了原油中烷烃含量、nC 21 - / nC 22 + 比值、 甾烷 C 29 αααββββ+αα比值、 烷烃主峰碳数、 δ13 C 值、 原油密度和粘度等地球化学指标的变化规律, 表明利津和牛庄洼陷内石油具有 “ 离心” 式运移的典型特征, 反映了压实流盆地古流体势场对油气运移的控制作用。 研究结果对压实流盆地油气运移、 聚集理论模型和模拟方法的研究具有重要的地质意义。

GEOCHEMICAL CHARACTERISTICS AND SIGNIFICANCE OF PETROLEUM MIGRATION IN E s 3 AND E s 4 MEMBERS,DONGYING DEPRESSION

The characteristics of petroleum migration of E s 3 and E s 4 members in Dongying depression were investigated by using a lot of geochemical indicators which are biological markers, carbon isotopes and oil alkane chromatography. The correlations of oil with source rocks proved that source rocks of E s 3 and E s 4 members in Lijin and Niuzhuang hollows provided petroleum sources for their surround area. The variations of alkane contents, nC 21 -/nC 22 +, δ 13 C, sterane C 29 αααββββ+αα , density and viscosity of oil have been analysed according to the principle of geochromatography. Evidence shown that petroleum migration was mainly in chromatography which has characteristics of centrifugal way within Lijin and Niuzhuang hollows, and reveals that the field of paleo fluids potential controlled hydrocarbon migration in compactional basins. The results can be important in studies of theoretical models and simulation methods of petroleum migration and accumulation for Mesozoic and Cenozoic basins of East China.