断陷盆地多期构造变形特征与油气聚集——以海拉尔—塔木察格盆地南贝尔凹陷为例

通过对海拉尔—塔木察格盆地南贝尔凹陷多期构造变形特征与沉积充填类型、烃源岩发育特征、圈闭类型、输导体系等油气成藏的主控因素间的相互响应配置关系研究,从盆地及凹陷内部2个层次分析了构造样式的控油作用。指出从盆地级别角度来看,南贝尔凹陷多期构造演化过程塑造了非旋转地堑/旋转半地堑—滚动半地堑—复式半地堑—走滑半地堑等多种凹陷结构变形。不同凹陷结构决定了沉积体系充填类型及砂体展布特征,并影响了烃源岩的形成与分布,形成了垂向上不同层位的多样生储盖组合,进而控制了多层位不同油藏类型的叠置复式成藏组合。而从凹陷内部构造变形分析得出发育的构造样式可划分为裂陷期断陷型、断拗期张扭型、反转期扭压反转型3期3大类18种类型,裂陷期发育的断陷型构造样式控制下形成的圈闭是原生油藏油气聚集最有利的场所;反转期发育的挤压构造是形成次生油藏的有利指向;断拗期及反转期发育的构造样式构建了多种类型断—砂输导体系。总体上断陷盆地多期构造变形特征对生、储、圈、运等油气成藏的关键因素具有控制作用,从而决定了油气的分布规律。 

Multi-stage structural deformation features and hydrocarbon accumulation in faulted basin: a case study in Nanbeier Sag of Hailar-Tamtsag Basin

The control of structural style on petroleum was analyzed through studying the relationship between multi-stage tectonic deformation features and the main factors controlling hydrocarbon accumulation,such as sedimentary filling type,hydrocarbon source rock generation feature,trap type and pathway system,etc.The controlling effect of structural style on petroleum in basin and depression was analyzed.From the aspect of basin level,structural deformations from non-rotating graben/rotating half graben,rolling half graben,duplex half graben,to slip half graben generated in the Nanbeier Sag during tectonic evolution.Various sag structures determined the filling types of sedimentary system and the distribution features of sand body,further influenced the generation and distribution of source rock,resulted in various hydrocarbon generation and accumulation assemblages in different formations,and finally controlled the superimposed composition of various reservoir types.Tectonic styles were classified into 3 stages,3 big types(rift type during chasmic stage,extensional-twist type during fault and depression stage,and torsional reversed type during inversion stage) and 18 types.Compressional structures of inversion stage were advantage points in secondary oil reservoirs.The structural styles of faulted-depression and inversion stage constructed multiple types of fault-sand body pathway system.The deformation features of fault basin controlled the key elements for hydrocarbon generation,reserve,trap and migration,and further determined the distribution of oil and gas.