鄂尔多斯盆地陕北斜坡带三叠系延长组和侏罗系油气成藏期研究

通过对鄂尔多斯盆地烃源岩的生烃史、构造运动特征、包裹体均一温度和伊利石K-Ar同位素定年的研究,结合研究区的裂缝发育特征,综合分析了三叠系延长组和侏罗系油气成藏期.鄂尔多斯盆地形成演化过程中经历了多期构造运动,其中影响最大的是早白垩世末期的构造运动.长7段泥质烃源岩在早白垩世初期开始大量生烃,对侏罗系延9段裂缝储层和三叠系延长组伊利石K-Ar同位素定年以及对储层流体包裹体均一温度分析显示,陕北斜坡带三叠系延长组油藏形成于早白垩世的早中期,而侏罗系延安组的油藏则形成于早白垩世末的构造抬升期,对应时间为晚白垩世早—中期.

Study on oil and gas accumulation period of Yanchang Formation of Triassic and Jurassic in North Shaanxi slope zone,Ordos Basin

Oil and gas accumulation period of Yanchang Formation of Triassic and Jurassic is systematically analyzed by combining the fracture distribution feature with the researches of generation hydrocarbon history of source rock,characteristic of tectonic movement,homogenization temperature of fluid inclusion and isotope dating of illitic K-Ar in Ordos Basin.It is shown that there are multiphase tectonic movements in the formation and evolution process of Ordos Basin.Of them,the tectonic movement in the end stage of the early Crataceous has the greatest influence.The argillaceous source rock of Chang 7 member starts to generate hydrocarbon on a large scale in the initial stage of Early Cretaceous.The illitic K-Ar isotope dating of the fractured reservoir of Y9 member of Jurassic and the sandstone reservoir of Yanchang formation of Triassic and the analysis of reservoir fluid inclusion homogenization temperature show that,the oil pool of Yanchang formation of Triassic in North Shaanxi slope zone is formed in the early--middle period of Early Cretaceous,while the oil pool of Yan'an formation of Jurassic is formed in the structure uplifting period in the end stage of Early Cretaceous,which is corresponding to early--middle period of Late Cretaceous.