海拉尔盆地乌尔逊-贝尔凹陷的构造特征及其对油气成藏的影响

海拉尔盆地乌尔逊-贝尔凹陷是叠置于内蒙-大兴安岭古生代碰撞造山带的中新生代盆地,主要发育白垩系和第三系、第四系,其中以下白垩统为主。乌尔逊-贝尔凹陷在中新生代经历了多期变形作用,构造特征十分复杂,主要发育4个方向的构造带,其中北东向、北东东向和南北向断层带形成较早且长期活动;北西向断层带形成较晚,对上述三个方向构造主要起改造作用。研究区的构造不仅影响了烃源岩的分布、油气运移和聚集,而且影响了圈闭的形成和油气分布,是研究区有利的油气聚集带。

STRUCTURAL FEATURES AND THEIR IMPACTS ON HYDROCARBON ACCUMULATION IN URXUNBEIER DEPRESSION IN HAILAER BASIN

Urxun-Beier depression in Hailaer basin is the Mesozoic and Cenozoic basin are located in the Paleozoic orogenic belt in Inner Mongolia-Daxing′anling area. Cretaceous system together with Tertiary system and Quaternary system occur in the basin, and the Lower Cretaceous is the predominant. Urxun-Beier depression experienced deformation for many times during Mesozoic and Cenozoic, the structural features are complicated. Four directions of structural belts are found in the research area. The faults of NE, NEE and NS directions were formed earlier, being active for a long time, and controlling the evolution of the basin; the faults of NW direction were formed later, remaking the older structures. The four directions of structural belts control the distribution of source rocks, hydrocarbon generation, migration and accumulation as well as trap formation in the basin, therefore serving as zones favorable for hydrocarbon accumulation.