济阳坳陷车镇凹陷沙河街组三段沉积充填样式及断裂坡折带的控制作用

The Control Effect of Sedimentary Filling Patterns and Fault Slope Break Zones of Sha 3 Member of Shahejie Formation in Chezhen Sag,Jiyang Depression

综合应用岩心、常规测井及地震等资料,对渤海湾盆地济阳坳陷车镇凹陷古近系渐新统沙河街组三段(以下简称沙三段)的层序地层、沉积充填样式及主控因素进行了深入研究。结果表明,研究区沙三段可划分为3个三级层序,大体对应于沙三下亚段、沙三中亚段、沙三上亚段;区内主要发育扇三角洲、湖底扇、河流三角洲、湖泊(包括滨浅湖和深湖)等沉积体系;断裂坡折带对沉积体系或沉积充填样式具有最重要的控制作用:凹陷北部陡坡带凸起边缘的断裂坡折控制着扇三角洲近端的粗砂砾岩沉积,凹陷边缘带的二级断裂控制着扇三角洲前缘和湖底扇的砂质沉积,南部缓坡带的断裂坡折控制着河流三角洲和湖底扇沉积的发育和分布,凹陷中部的断裂坡折控制着凹陷的沉积中心;三角洲和湖底扇相带的发育和分布,尤其是三角洲前缘砂体和湖底扇砂体具有良好的储集性能,构成盆内寻找砂岩油气藏的最有利相带。

Based on the comprehensive application of the core,conventional well logging data and seismic data,etc.,the sequence stratigraphy,sedimentary filling patterns and main controlling factors of Sha 3 member of Shahejie Formation of Paleogene Oligocene in Chezhen Sag,Jiyang Depression,Bohai Bay basin were studied thoroughly.The result shows that Sha 3 member can be divided into three third-order sequences,which correspond to Sha 3 lower sub-member,Sha 3 middle sub-member,and Sha 3 upper sub-member in the study area.The sedimentary systems of fan delta,sublacustrine fan,river delta,lake(including shore-shallow lake and deep lake)are mainly developed in the area.Fault slope break zone is the most important control effect on the sedimentary system or sedimentary filling patterns.The fault slope break at the raised edge of the fault slope break zones in the north of the sag controls crude glutenite deposition near the fan delta,while the second-order fracture in the marginal zone of the sag controls the sandy sediments of fan delta front and sublacustrine fan;The fault slope break in the southern gentle slope zone controls the development and distribution of deposits of fluvial delta and sublacustrine fan,while the fault slope break in the middle of the sag controls the depocenter of the sag.The development and distribution of delta and sublacustrine fan facies belts,especially the delta front sand body and sublacustrine fan sand body with good reservoir performance,constitute the most favorable facies belts for finding sandstone reservoirs in the basin.