断陷湖盆重力流水道地震沉积学研究——以歧南地区沙一段为例  

Seismic sedimentology research on fault-depressed lacustrine basin gravity flow channels of Oligocene Es_1 in Qi'nan area,Qikou Sag

作　　者：刘化清[1,2] 洪忠[1,2] 张晶[1,2] 牛海青[1,2] 苏明军[1,2] 李双文[1,2] 

机构地区：[1]中国石油勘探开发研究院西北分院,甘肃兰州730020 [2]中国石油天然气集团公司油藏描述重点实验室,甘肃兰州730020

出　　处：《石油地球物理勘探》2014年第4期784-794,7,共11页Oil Geophysical Prospecting

基　　金：国家重大科技专项(2011ZX05001-003);中国石油"歧口富油气凹陷大油气田勘探及综合配套技术研究";"地震沉积学软件系统研发及应用"项目联合资助

摘　　要：本文以歧口凹陷歧南地区沙一段为例,分析了断陷湖盆以沟道型砂质碎屑流为主体的重力流沉积的结构与构造、测井响应、地震相模式以及主水道的平面分布格局及纵向演化。研究发现:1以歧南地区沙一段为代表的陆相断陷湖盆重力流沉积至少包括砂质碎屑流、滑塌、浊流等3种成因沉积类型,以沟道化砂质碎屑流为主体,悬浮组分含量高。2断陷湖盆重力流水道横断面的地震相模式有U型或V型、碟片性、蠕虫型、纺锤型(透镜状)等4种类型,很可能依次与流体能量由强而弱的变化相对应。3构造活跃期湖盆底形较陡,沿洼槽发育的重力流水道窄而顺直,对下伏地层刻蚀显著;构造相对平静期湖盆底形平坦,水道宽度及弯曲度增大,对下伏地层侵蚀相对较弱。Based on the first Member of Shahejie Formation(Es1)in Qi'nan area,Qikou Sag,we conducted seismic sedimentology analysis,including sedimentary textures, well logging characteristics,seismic facies models,and channel distribution of a faulted-lacustrine basin gravity flow depositional system dominated by channel sandy debris flow.The following observations have been obtained:1There are at least three types of gravity-flow deposits developed in the Oligocene fault-depressed lacustrine basin:sandy debris flow,slump,and turbidite,in which the sandy debris flow with considerable suspension content is the main depositional type.2Seismic facies models of fault-depressed lacustrine basin gravity-flow channels can be divided into U-shaped(or V-shaped),saucerlike,worm-like,and spindle-shaped(lenticularlike)facies,which are probably related to the changes from strong fluid energy to weak fluid energy.3When tectonic movement was active,the lacustrine basin was steep,and gravity-flow channels developed along valleys were narrow and straight with obvious erosion to underlain strata;when the tectonic movement was inactive,the lacustrine basin was flat,and channels were much wider with less erosion to underlain strata.

关 键 词：地震沉积学 重力流水道 断陷湖盆 歧南地区 沙一段 

分 类 号：P631[天文地球—地质矿产勘探]