【作者】 张美华；

【导师】 邓军；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2010， 硕士

【摘要】 本文综合运用层序地层学、沉积岩石学、地震沉积学、地球物理学等理论,对柴达木盆地乌南-绿草滩地区下油砂山组(N21)地层开展地震沉积学研究。在进行传统的测井、录井、取芯资料分析的基础上,结合地震沉积学的技术方法,将地质研究成果由点及面,由面及体拓展,细化并深入研究沉积微相发育特征。工区位于柴达木盆地西部坳陷区,整体为一由南东向北西方向倾没的鼻状背斜,沉积物源是位于工区西部的昆仑山脉,沉积物大体呈自西向东搬运的趋势,但在乌南-绿草滩构造带,由于受局部构造因素的影响,N21时期沉积物源表现出西-北西、南-南东方向共同存在的现象。通过对岩芯、录井、测井以及沉积构造等地质资料的综合分析,并结合前人研究成果,建立起了乌南-绿草滩地区下油砂山组层序地层格架方案,下油砂山组地层整体为一个三级层序单元,将其划分为7个四级层序(SQⅠ-SQⅦ),174个五级层序,并确立了基本的沉积相模式。下油砂山组地层主要发育坳陷湖泊背景下的滨浅湖滩坝-三角洲前缘沉积体系,地层由老至新表现为湖退过程,沉积相类型从单一的滨浅湖滩坝逐渐演变为三角洲前缘-滨浅湖滩坝沉积体系。在上述认识的基础上,运用地震沉积学的技术方法(90°相位转换、分频处理和地层切片),对工区三维地震数据体开展地层切片研究,通过提取相应层序界线内的地震均方根振幅属性,结合沉积学认识,绘制出了下油砂山组内各四级层序的沉积微相平面图,利用地震层内等比插值技术,对下油砂山组174个五级层序开展地层切片研究,明确了各四级层序内部的沉积演化特征。在基于地层切片的沉积微相图上,划分出了七种沉积微相类型:滨浅湖坝、滨浅湖滩、滨浅湖泥、三角洲前缘水下分流河道、三角洲前缘水下分流河道间、三角洲前缘河口坝、三角洲前缘席状砂。通过综合分析,三角洲前缘和滨浅湖滩坝砂体是本区最有利的储集体,具有良好的油气勘探前景。更多还原

【Abstract】 This dissertation takes sequence stratigraphy, sedimentology, seismic sedmentology and Geophysics as instruction, and focus on the seismic sedimentary study of the lower Pliocene(N21) formation in Wunan-Lvcaotan Zone. Based on the analysis of well logging and core, combine with the technics of seismic sedmentology, we carry out the sedimentological study, and the seismic sedimentary technics make the findings more realiable. The study area locates in the western depression of Qaidam Basin, the integral structure is an anticline inclined to NW, the general depositional migrate direction is from west to east, but in the study area, under the effect of local tectonic activities, there are two provenance directions: W-NW and S-SE.We established the sequence stratigraphic framework, the N21 formation is a third-order sequence unit, and divided into 7 fourth-order sequences(SQⅠ-SQⅦ), 174 fifth-order sequences. We created the general sedimentary facies model, the principal facies in the study area is beach, bar and delta front in shore-shallow lake. Through the time, the water depth of the depositional environment become shallow.By the means of seismic sedmentology (90°-phase shift, frequency conversion and stratal slicing), we make a series of stratal slices. The properties extracted from these slices represent the sedimentary facies, so we draw microfacies maps for every fourth-order sequence refer to the stratal slices, and maps for the fifth-order sequences to study the evolution of the sedimentary system.On the microfacies maps, there are 7 microfacies types: bar, beach, lake mudstone, submarine distributary channel, interchannel, mouth bar, distal bar. The sand in delta front, beach and bar of the shore-shallow lake are the favorable reservoir rocks of the study area.更多还原