【摘要】 新生代以来准南前陆地区发育一系列冲断褶皱带,本文对该褶皱带的生长地层识别、地震剖面构造解析和平衡剖面恢复,并结合前人磁性地层学年龄结果,对准南冲断构造进行了系统分析。结果表明,准南山前三排冲断褶皱带形成时间自天山向盆地逐渐变新,其中第一排的构造发生时间为~7Ma,第二排构造为~2Ma,第三排构造在1Ma之后。系统的沉积层序分析表明,准南地区的烃源岩、储集层、盖层和圈闭条件均与天山南缘的库车地区差别不大(除盖层非盐岩层外),但是准南地区相对较晚的构造形成时间和双层滑脱层系(下滑脱层为中侏罗统的煤层,上滑脱层为安集海河组泥岩)的发育,可能是造成准南中上成藏组合没有形成大型油气藏的主要因素。本文提出,准南地区下部成藏组合(即被下白垩统区域盖层覆盖的上侏罗统储集层系)是源于侏罗系煤系地层的大型天然气藏形成的有利目标,应在今后的勘探中给予高度关注。更多还原

【Abstract】 A series of thrust-fold belts were formed in the southern Junggar foreland basin during the Cenozoic.This paper provides regional structural analyses of the thrust fold belts based on the growth strata,interpretation of seismic profiles,and balanced cross-sections,together with available magnetostratigraphic results.Our analyses show that three paralleled rows of anticlinal belts have been developed sequentially from the south to the north since ~7 Ma for the southern,~2 Ma for the middle,and ~1 Ma for the northern anticlinal belt,respectively.The systemic studies of the sedimentary sequences show that the source rocks,reservoirs,seal rocks,and traps between the northern and southem margins of the Tian Shan are similar and there are three petroleum systems (or plays) in the southern Junggar Basin.The reason why there has been no discovery large oil-gas field of so far in the southern Junggar may be mainly due to the very late deformation and the existence of two detachment layers,i.e.,the upper detachment layer of the Ahjihaihe Formation (E 2-3 a) and the lower detachment layer of the middle Jurassic coal beds (J 2 x).This paper proposes that the lower play,i.e.,the Upper Jurassic reservoirs sealed by the Lower Cretaceous,is favorable for forming large-scale oil-gas field and should be potential targets for future exploration.更多还原