热带海洋学报

• •    

基于AUV观测数据的南海东沙北部浅表层精细地质特征及其灾害因素分析

李彦杰1, 朱友生1, 陈冠军1, 王姝1, 王微微2   

  1. 中海油田服务股份有限公司物探事业部, 天津 300459;

    2. 中国石油大学(华东)控制科学与工程学院, 山东 青岛 266580

  • 收稿日期:2022-02-14 修回日期:2022-06-14 出版日期:2022-06-17 发布日期:2022-06-17
  • 通讯作者: 朱友生
  • 基金资助:

    自然科学基金面上项目(42176083)

Analysis of fine surface geological characteristics and disaster factors in the northern Part of Dongsha, South China Sea based on AUV data

LI Yanjie1, ZHU Yousheng1, CHEN Guanjun1, WANG Shu1, WANG Weiwei2   

  1. Geophysical-China Oilfield Services Limited, Tianjin 300459, China;

    2. College of Control Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China

  • Received:2022-02-14 Revised:2022-06-14 Online:2022-06-17 Published:2022-06-17
  • Contact: yousheng zhu
  • Supported by:

    National Natural Science Foundation of China (42176083)

摘要: 全面认识海底浅表层地质特征是识别评价浅层海洋地质灾害的基础,对海洋资源开发、海洋工程建设等有重要意义。南海东沙北部有多个油气田正在勘探开发,但目前缺少对东沙北部陆缘海底浅表层地质精细特征的系统分析,不利于该区域海洋工程建设的顺利开展。针对南海东沙北部海域外陆架区域(100-400m),利用AUV(Autonomous Underwater Vehicle)搭载多波束、浅地层剖面系统采集了海底地形地貌、浅层沉积结构等高精度数据资料,结合对二维地震、沉积物等资料的获取和分析,识别了研究区浅表层地质灾害因素,并评估其风险性。调查发现,研究区海底表面发育海底沙波、陡坎、冲沟等地貌。海底浅层未见浅层气,但发育多处埋藏古河道。海底沙波的大小和分布特征具有显著空间差异,波高大于1m的沙波主要分布于134-143m、168-187m、205m以深区域,海底沙波的发育可能与内波过程有关,能够在现代动力条件下发生移动。研究区一处陡坎和海底冲沟相伴发育,陡坎坡度超过20°,可能与贯穿浅层的断层有关。海底表层沉积物总体相对稳定,浅表层海底地质灾害因素主要为海底沙波、断层、海底陡坎和埋藏古河道。这些地质灾害因素均具有潜在的破坏性,可能给海洋工程设施的施工维护带来不利影响。

关键词: AUV, 地质特征, 灾害因素, 南海, 沙波

Abstract: A comprehensive understanding of the shallow surface geological characteristics of the seabed is the basis for the identification and evaluation of shallow Marine geological disasters, which is of great significance to the development of Marine resources and the construction of Marine engineering. Several oil and gas fields are being explored and developed in the northern part of Dongsha, South China Sea. However, the lack of systematic analysis of the fine geological features of the shallow surface of the seabed in the northern margin of Dongsha is not conducive to the smooth development of Marine engineering construction in this area. Outside the north sea to the east of the south China sea sand shelf area (100-400 m), using the AUV (Autonomous Underwater Vehicle) with multi-beam system, shallow profile collected underwater topography, shallow sedimentary structures such as high precision data, in combination with the 2 d seismic, sediment data acquisition and analysis, to identify factors play a geological disasters in the study area, and evaluate its risk. The survey found that the seabed surface of the study area developed sand waves, steep ridges, gullies and other geomorphology. There is no shallow gas in the shallow seabed, but there are many buried ancient channels. The size and distribution characteristics of seabed sand waves have significant spatial differences. The sand waves larger than 1m are mainly distributed in regions with depths of 134-143m, 168-187m and 205m. The development of seabed sand waves may be related to the internal wave process and can move under modern dynamic conditions. A scarp with a slope of more than 20° is developed in the study area, which may be related to a fault that runs through the shallow layer. The seabed surface sediments are generally relatively stable, and the shallow seabed geological hazard factors are mainly seabed sand waves, faults, seabed scarps and buried ancient channels. All these geological hazard factors are potentially destructive and may adversely affect the construction and maintenance of Marine engineering facilities.

Key words: AUV, Geological characteristics, Disaster factors, The South China Sea, Sand wave