柴达木盆地英雄岭地区古近系油气成藏过程及其演化特征

通过构造演化特征研究，结合烃类包裹体分析和典型油气藏精细解剖，阐述了柴达木盆地英雄岭地区古近系下干柴沟组上段油气藏的形成和演化过程。研究结果表明： ①英雄岭地区古近系下干柴沟组上段形成于半咸化—咸化湖泊—盐湖环境，发育以纹层状灰云岩为储集层、富含有机质、广覆式分布的源储一体型油气藏；②研究区下干柴沟组上段共经历3期油气充注，第Ⅰ期烃类包裹体为单一液相油包裹体，反映了早期低熟原油的运移和充注；第Ⅱ期烃类包裹体为单一液相油包裹体，反映了一幕中等成熟原油的运移和充注；第Ⅲ期烃类包裹体为气液两相油包裹体，反映了一幕高成熟原油的充注。③研究区油气具有3期成藏的特征：上干柴沟组沉积中晚期，在下干柴沟组上段形成了低饱和度-低熟油藏；上油砂山组沉积期，低熟—成熟油气向盐间储集层和高渗带聚集形成了油气高产区；狮子沟组—七个泉组沉积期，成熟—高熟油通过双层断裂接力输导运移至干柴沟组上段及以上地层运聚形成构造油气藏。

Hydrocarbon accumulation and evolution characteristics of Paleogene in Yingxiongling area,Qaidam Basin

Through the study of structural evolution characteristics, combined with the analysis of hydrocarbon inclusions and fine dissection of typical oil and gas reservoirs, the formation and evolution process of oil and gas reservoirs in the upper member of Paleogene Xiaganchaigou Formation in Yingxiongling area of Qaidam Basin were analyzed. The results show that:(1) The upper member of Xiaganchaigou Formation in Yingxiongling area experienced a semi saline lake, saline lake and salt lake environment during the Paleogene period, and formed a large area of source-reservoir type oil and gas reservoir dominated by laminated calcite dolomite which is rich in organic matters.(2) The upper member of Xiaganchaigou Formation in the study area has experienced three stages of oil and gas filling. The hydrocarbon inclusions in the first stage are single liquid oil inclusions, reflecting the migration and filling of early low mature crude oil. The hydrocarbon inclusions in the second stage are single liquid oil inclusions, which reflects the migration and filling of medium mature crude oil. The hydrocarbon inclusions in the third stage are gas-liquid two-phase oil inclusions, reflecting an episode of filling of highly mature crude oil.(3) The oil and gas in the study area are characterized by three stages of accumulation. In the middle and late stages of the deposition of Shangganchaigou Formation, reservoirs with low saturation and low maturity formed in the upper member of Xiaganchaigou Formation. In the sedimentary period of Shangyoushashan Formation, low mature to mature oil and gas accumulated to the salt reservoirs and high permeable zones, forming a high oil and gas production area. During the sedimentation period of Shizigou Formation to Qigequan Formation, maturehighly mature oil migrated to the upper member of Ganchaigou Formation and above through the transport of double layer faults to form structural oil and gas reservoirs.