海拉尔盆地乌尔逊凹陷油气成藏期次分析

目的研究海拉尔盆地乌尔逊凹陷油气成藏期次。方法圈闭形成时期、烃源岩生排烃史、储层自生伊利石测年和包裹体均一温度法。结果海拉尔盆地乌尔逊凹陷油气成藏期主要分为两个大的阶段:第一阶段油气成藏时期大约在距今120~90 Ma,相当于伊敏组沉积时期,是海拉尔盆地乌尔逊凹陷最主要的成藏时期。油气大规模注入储层时期应该在105~90 Ma,相当于伊敏组二三段沉积时期,此时期为烃源岩大量生排烃时期,油气运移动力充足,有利于油气运移并聚集成藏;第二阶段为青元岗组沉积至今。青元岗组沉积以来,发生过近东西向的挤压反转,使已形成的油气藏重新调整,同时,二次生成的油气继续注入成藏。结论乌尔逊凹陷油气成藏时期研究取得新的认识,对于盆地下一步勘探具有重要的指导意义。

Research on the formation stages of oil-gas reservoirs in Wuerxun Depression

Ahn To make a research on the formation stages of oil-gas reservoirs in Wuerxun Depression of Hailaer Basin. Methods By the formation history of traps, hydrocarbon generated and hydrocarbon expulsed process, illite dating, homogenization temperatures of fluid inclusion. Results There are two main formation stages of oil-gas reservoirs in Wuerxun Depression of Halaer Basin. The first stage is about 120 -90 Ma,which is corresponding to sedimentary period of Yimin Formation, which is the main formation time of oil-gas reservoirs in Wuerxun Depression of Halaer Basin. The great majority of formation period of oil and gas is 105 -90 Ma,which is corresponding to secondthird segment sedimentary period of Yinmin Formation, it is the abundant period of hydrocarbon generated and hydrocarbon expulsed process, sufficient migration force is helpful to formation of oil and gas reserviors. The second stage is from Qinyuangang Formation to now. On one hand, the oil-gas reservoirs formed in the first stage is adjusted ; on the other hand, it is the second formation process of oil-gas reservoirs. Conclusion The new cognition about formation stages of oil and gas is important for next exploration of Hailaer Basin.