柴达木盆地西南地区典型油田油气充注期研究

Hydrocarbon Charging History of Typical Oilfields in Southwestern Qaidam Basin

通过包裹体岩相学、荧光光谱、红外光谱和显微测温等分析,对柴西南地区红柳泉、尕斯库勒和英东3个典型油田的油气充注期进行了研究。研究结果表明：1柴西南地区含油气包裹体发育,含油包裹体丰度（GOI）为5%~90%;2根据包裹体颜色、产状、宿主矿物等特征,可以划分为2类油气包裹体组合（黄色荧光包裹体和蓝色荧光包裹体）,反映了来自2期油气充注过程的产物;3包裹体荧光光谱的波峰范围和红外光谱的甲基含量特征均反映出蓝色荧光包裹体的成熟度高于黄色荧光包裹体。通过包裹体均一温度,结合埋藏史模拟结果,综合分析了典型油田的油气充注时间。尕斯库勒油田和红柳泉油田2期油气充注对应的时间分别约为26Ma和10Ma;而英东油田2期油气充注对应的时间分别为10Ma和5Ma。晚期构造演化与油气充注过程相匹配决定了油气的保存条件和富集程度。

The hydrocarbon charging history of Hongliuquan oilfield,Gasikule oilfield and Yingdong oilfield is studied in this paper by synthetically adopting fluid inclusion petrography,fluorescence spectrum,infra red spectrum, microthermometry analysis and burial history modelling. The results illustrate that grain with oil inclusions is well developed in the southwestern Qaidam Basin with the index of grain with oil in- clusion （GOD value between 5%-90%. According to the characteristics of fluorescence color,occurrence, host mineral of oil inclusion,two fluid inclusion assemblages can be classified as yellow fluorescence inclu- sion and blue fluorescence inclusion. The peak of fluorescence spectrum and methyl content of infrared spectrum both reflect that the maturity of blue fluorescence inclusion is higher than that of yellow fluores- cence inclusion. Combined with homogenization temperature of fluid inclusions and thermal evolution anal- ysis,it is confirmed that there were mainly two episodes of hydrocarbon charging in the southwestern Qaid- am Baisn. The charging time of Gasikule oilfield and Hongliuquan oilfield is 26Ma and 10Ma,respectively. The charging time of Yingdong oilfield is separately 10Ma and 5Ma. The later hydrocarbon charging process and tectonic evolution control the preservation condition and hydrocarbon enrichment.