内蒙古海拉尔盆地油气成藏期次分析

利用储层自生伊利石测年法、烃源岩生排烃史法和包裹体均一温度法等综合分析了海拉尔盆地油气成藏期次。综合分析表明:海拉尔盆地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在距今120～80 Ma,相当于伊敏组沉积时期—青元岗组沉积早期,是海拉尔盆地各凹陷最主要的成藏时期,油气大规模注入储层时期应该在距今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,有利于油气发生运移并聚集成藏;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。优质的烃源岩、断裂和稳定的厚层泥岩是控制研究区油气藏形成和分布的主要因素。

Formation Stages of Oil-gas Reservoirs in Hailaer Basin, Inner Mongolia

On the basis of illite dating method,hydrocarbon generated and hydrocarbon expulsed process and homogenization temperatures of fluid inclusion,the formation stages of oil-gas reservoirs in Hailaer basin were studied.The results show that there are two main formation stages of oil-gas reservoirs in Hailaer basin.The first stage is about 120-80 Ma,which is corresponding to the sedimentary period of Yimin Formation-early se-dimentary period of Qingyuangang Formation,and it is the main formation time of oil-gas reservoirs in Hailaer basin.The great majority of formation period of oil and gas is 105-90 Ma,which is corresponding to the second-third segment sedimentary period of Yinmin Formation,and it is the abundant period of hydrocarbon generated and expulsed processes,in which the sufficient migration force is helpful to the formation of oil and gas reservoirs.The second stage is from the time that Qinyuangang Formation was deposited to now.During the second stage,the oil-gas reservoirs formed in the first stage was adjusted,and at the same time the second formation process occurred in the oil-gas reservoirs.The fine hydrocarbon,faults and sustained thick mudstone control the formation and distribution of oil-gas reservoirs in the study area.