Abstract: The petroleum system division and reservoir-forming history of the Northern Fringe in Qaidam Basin were studied on the basis of characteristic description, evolution modeling and oil-to-source correlation of hydrocarbon source rocks.It is concluded that the primary hydrocarbon source rocks in the fringe are those source rocks developed in Middle-Lower Jurassic,including mudstone in coal measure,carbonaceous mudstone and coal seam.There are five types of organic matters(Ⅰ,Ⅱ₁,Ⅱ₂,Ⅲ₁ and Ⅲ₂) in those source rocks.Most of the Middle-Lower Jurassic source rocks are in the over-maturity stage.The source rocks are of the maximum accumulative generation intensity over ten thousands kg/m² and expulsive intensity over four thousands kg/m² in the stage of the Upper Gancaigou Formation to the Lower Youshashan Formation of the Lower Jurassic,while maximum accumulative generation intensity is over two thousands kg/m² and expulsive intensity is below one thousands kg/m² in the Middle Jurassic.There are two petroleum systems in this fringe.One is in J₁-R(!) oil and gas system,and the key moment for hydrocarbon generation and expulsion is in the deposition stage of Lower Ganchaigou to Upper Youshashan Formation.Another is in J₂-J₃(!) system with a key moment during deposition of Lower Youshashan-Shizhigou Formation.

Key words: Qaidam Basin, northern fringe, hydrocarbon source rock evolution, oil-to source correlation, petroleum system, reservoir forming history

摘要： 通过对柴北缘烃源岩演化历史模拟和油气源对比,分析了其成藏历史,研究并划分了该区的含油气系统.得出的主要结果是:①柴北缘主要烃源岩为中、下侏罗统煤系烃源岩,分为Ⅰ、Ⅱ₁、Ⅱ₂、Ⅲ₁、Ⅲ₂5种有机质类型;②中、下侏罗统烃源岩大多已超过过成熟阶段.下侏罗统在上干柴沟组-下油砂山组沉积时期进入大量生、排烃阶段,中侏罗统则在下油砂山组-狮子沟组沉积时期进入生、排烃阶段;③柴北缘可分为两个含油气系统:一个是J₁-R(!)含油气系统,生、排烃阶段在下干柴沟组-上油砂山组沉积时期;另一个是J₂-J₃(!)含油气系统,生、排烃阶段在下油砂山组-狮子沟组沉积时期.

关键词: 柴达木盆地, 北缘, 烃源岩演化, 油气源对比, 含油气系统, 成藏历史