北部湾盆地涠西南凹陷断裂系统成因的砂箱实验研究及启示

高 校　地　质　学　报

Geological Journal of China Universities

2009 年 6 月，第 15 卷，第 2 期，246-255页June 2009，Vol. 15， No.2， p. 246-255北部湾盆地涠西南凹陷

断裂系统成因的砂箱实验研究及启示

收稿日期：2008-01-09；修回日期：2009-03-31

基金项目：涠西南凹陷断层系统分析及其与油气成藏关系研究；中海石油（中国）有限公司湛江分公司委托中国石油大学（北京）完成的横向合作 项目（Z2006SLZJ-FN0211）共同资助

作者简介：孟令箭，男，硕士生，从事构造地质学研究；E -mail: barbarity@

摘要：北部湾盆地涠西南凹陷的断裂系统十分复杂，为了揭示其成因机制，在三维地震资料构造解析的基础上，应用砂箱物理模拟技术，对涠西南凹陷的形成机制进行了系统研究。结果表明，南北向的“不协调伸展作用实验模型”能够成功地模拟涠西南凹陷晚始新世以来复杂的断裂系统，断裂系统的主体特征在这一实验模型中均得到了很好的再现。涠西南凹陷复杂的断裂系统是在基底先存构造基础之上，在递进变形过程中逐渐形成的，其裂陷期（晚始新世-渐新世）断裂系统是在一个伸展期内形成（南北向伸展）、并非是多期构造叠加变形的结果。这一认识不但能够有效地指导涠西南凹陷三维地震资料的精细构造解释，同时也能够为南海周缘盆地的形成和演化研究提供借鉴。关键词：涠西南凹陷；砂箱模拟；断裂系统；成因机制

中图分类号：P618.130.1 文献标识码：A 文章编号：1006-7493(2009)-02-0246-10

孟令箭1，童亨茂2，蔡东升3，刘明全3，李绪深3

（1. 冀东油田 勘探开发研究院，唐山 063004；

2. 中国石油大学（北京） 油气资源与探测国家重点实验室，北京 102249；

3. 中海石油湛江分公司，湛江 524057）

Sandbox Modelling on Genetic Mechanism of Fault System in Weixinan

Depression of the Beibu -Gulf Basin and Its Inspiration

MENG Ling -jian 1, TONG Heng -mao 2, CAI Dong -sheng 3, LIU Ming -quan 3, LI Xu -shen 3

( 1. Exploration & Development Research Institute of PetroChina Jidong Oilfield Company, Tangshan 063004, China;2. State Key Laboratory of Petroleum Resource and Prospecting in China University of Petroleum, Beijing 102249, China;

3. Zhanjiang Branch of CNOOC Ltd, Zhanjiang 524057, China )

Abstract: The fault system of Weixinan Depression in the Beibu -Gulf Basin is very complex. In order to reveal the genetic mechanism, this paper applies sandbox modelling technologies to make a systemic analysis on the formation mechanism of Weixinan Depression fault system on the basis of systematic structural analysis of 3D seismic data. After several physical simulation experiments, the south -north direction experimental model of disharmonic extension can successfully reproduce the complicated fault system of Weixinan Depression, and the major characteristics have clear appearance in this experimental model. The complicated fault system of Weixinan Depression was formed gradually during progressive deformation on the basis of the pre -existed basement structure, and the fault system of main rifting phase (Late Eocene -Oliqocene) was formed just by one extension stage (NS trending), but not the result of multi -stage superimposed deformation. This understanding not only can interpretet the fine structure of 3D seismic data in Weixinan Depression, but also can provide a reference for studying the formation and evolution of the peripheal basins of the South China Sea.

Key words: Weixinan Depression; sand box simulation; fault system; formation mechanism