顺德北凹走滑变形特征及其控圈作用  

Strike-slip deformation characteristics and trap-controlling effects in Shunde north sag

作　　者：龚宇 尤丽 呙诗阳 窦婧瑛 周晨 高梦天 焦垚祺 郑飞 GONG Yu;YOU Li;GUO Shiyang;DOU Jingying;ZHOU Chen;GAO Mengtian;JIAO Yaoqi;ZHENG Fei(CNOOC China Limited,Hainan Branch,Haikou,Hainan 570100,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570100

出　　处：《中国海上油气》2024年第3期49-59,共11页China Offshore Oil and Gas

基　　金：中国海洋石油有限公司万亿大气区专项“南海大中型天然气田形成条件、勘探潜力与突破方向(编号:KJZH-2021-0003-00)”;中国海洋石油有限公司“十四五”重大科技项目“南海深水盆地油气运聚成藏分析与突破方向(编号:KJGG-2022-0103)”部分研究成果。

摘　　要：珠江口盆地顺德凹陷断裂特征及其控制形成的圈闭分布规律认识不清,一直制约该区勘探。新生代以来凹陷经历了多期构造变形和叠加,所形成的复杂走滑变形对圈闭形成具有重要控制作用。利用高精度三维地震资料以及新钻井成果资料,在精细构造解释的基础上,运用走滑及伸展定量分析技术,系统地开展顺德北凹走滑断裂特征描述、凹陷构造发育机制分析及走滑控圈作用研究。结果表明:①顺德北凹内部发育有负花型、复式负花型、Y型、复式Y型、多级Y型和多米诺式6种剖面断裂组合和剪切透镜体、羽列和雁行3种平面构造样式;②顺德北凹发育3期走滑作用,与伸展作用叠加控制凹陷构造演化,断陷期表现为强斜向伸展、弱走滑,断拗转换期表现为强走滑、弱伸展,陷期表现为弱走滑、弱伸展的构造发育机制;③发育凹陷带强走滑带S型增压转换控圈模式,缓坡带中走滑带两期走滑叠加控圈模式及低凸起弱走滑带右行左阶走滑推挤隆起控圈模式,其中凹陷带强走滑带S型增压转换控圈模式下形成的圈闭有效性好,为油气富集的重要场所。该成果指导了顺德北凹勘探突破,也为边缘凹陷多期走滑叠加下的构造演化理论研究以及勘探实践提供一种借鉴。The unclear fault characteristics and trap distribution regularities restrict the exploration of Shunde sag,Pearl River Mouth basin.Shunde sag has undergone multiple stages of tectonic deformation and superposition since the Cenozoic.The formed complex strike-slip deformation controls the formation of traps in the sag.High-precision 3D seismic data,new drlling data,structural explanations,and quantitative analysis technology of strike-slip and extension were used to study the characteristics of strike-slip faults,the structural development mechanism and the controlling effect of strike-slip on traps in Shunde north sag.Results showed that:OShunde north sag formed 6 fault combinations(negative pattern,compound negative pattern,Y-type,compound Y-type,multi-stage Y-type and domino-type)and 3 plane structural styles(shear lens,plume,and flying geese).@Shunde north sag formed 3 stages of strike-slip.Strike-slip and extension controlled the tectonic evolution of the sag.The fault period is characterized by strong oblique extension and weak strike-slip;the fault-depression transition period is characterized by strong strike-slip and weak extension;the depression period is characterized by weak strike-slip and weak extension.Shunde north sag developed 3 trap-controlling models:the development depression zone is a strong S-type strike-slip transform zone trap-controlling model;the slope zone is a two-stage strike-slip superimposed trap-controlling model;the low protrusion and weak strike-slip belt is a right-row and left-step strike-slip pushing trap-controlling pattern.The trap formed by the second model is good and is conducive to oil and gas accumulation.This study guides the exploration breakthrough of Shunde north sag.It provides a reference for the tectonic evolution theory and exploration practice under the superposition of multi-stage strike-slip in the edge sag.

关 键 词：珠江口盆地 顺德北凹 走滑作用 走滑强度 构造样式 圈闭形成 

分 类 号：TE122.3[石油与天然气工程—油气勘探]