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对中国南海北部陆缘珠江口盆地与琼东南盆地的区域不整合进行研究,结果表明:该区域受控于幕式岩石圈整体拉张作用,主要经历了3个沉降阶段:初始裂陷、主裂陷、及裂陷衰减阶段,控制盆地内断裂系统发育及阶段性活动,形成了以半地堑为主的构造样式.依据主控断裂与次级断裂的位置关系,将半地堑分为3大类:简单型,缓坡断阶型及陡坡断阶型;同时,根据地震相的外部形状与内部反射特征,对盆地内地震相进行划分,识别出5种地震相类型:平行-亚平行席状地震相、前积楔状地震相、充填状地震相、丘状地震相及乱岗形滩状地震相.通过分析各种地震相的垂向分布规律和指相意义,结合研究区沉积背景及单井资料,将地震相转变为沉积相,建立了南海北部陆缘盆地各类半地堑充填模式,划分出三角洲、扇三角洲、深水扇等沉积相,明确了不同类型半地堑沉积充填模式的区别,为生储组合分析及勘探前景研究提供依据.
The regional unconformities in the Pearl River Mouth Basin and Qiongdongnan Basin in the northern margin of the South China Sea are studied. The results show that the area is controlled by the overall pullout of the episode lithosphere, and mainly undergoes three subsidence stages: initial rifting, Rifting and rifting and decollement, controlled the development of fault system and the stage activities in the basin, and formed a structural pattern mainly of half-graben.According to the relationship between the main fault and the secondary fault, the half-graben was divided into In the meantime, based on the external shape of the seismic facies and the internal reflection features, the seismic facies in the basin are divided and five types of seismic facies are identified: parallel - subparallel Seismic facies, pre-quasi-wedge-shaped seismic facies, filled seismic facies, mound seismic facies and random gangland-shaped seismic facies.Based on the analysis of vertical distribution and significance of various seismic facies, combined with the sedimentary background of the study area And single-well data, the seismic facies was transformed into sedimentary facies. Various semi-graben filling patterns were established in the marginal basin of the northern South China Sea. Sedimentary facies such as delta, fan delta and deep-water fan were identified. The sedimentary facies of different types of semi- mode The difference provides the basis for the research on the reservoir combination analysis and exploration prospect.