【摘要】 以经典层序地层学理论为指导,对地质、岩心、钻井、测井及地震等资料进行综合分析,将歧口凹陷沙二段从下往上划分为2个三级层序SQ1和SQ2,对应层序界面为SB1和SB2,并在层序内部划分至体系域级别。层序界面在地震反射终端和岩性、电性等方面都具有明显的鉴别特征。其中SB1界面类型为构造成因的较高角度削截不整合面,可作为沙河街组内部的1个二级超层序界面;SB2为受湖平面变化控制的典型的三级层序界面。2个层序的划分反映了沙二段时期工区经历了2次较大规模的湖平面升降。更多还原

【Abstract】 The Es2 member in Qikou Depression has been divided into 2 third-class sequences of SQ1 and SQ2 from below with corresponding sequence interfaces being SB1 and SB2 through comprehensive analysis of geological,coring,drilling,logging and seismic data on the basis of typical sequence stratigraphy.The hierarchy of system tract is divided inside the sequence.The sequence interfaces show evident identifying characteristics in seismic reflection terminal,lithology,and electrical property.The SB1 interface is a high-angle truncated unconformity of tectonic genesis,and can serves as a second-class supersequence interface within Shahejie formation;the SB2 is a typical third-class sequence interface controlled by the change of lake level.These 2 sequences indicate that the study area had experienced twice large-scale lake level changes during Es2 period.更多还原