海洋地球物理探测技术在浅海井场地质灾害调查中的应用

Application of Marine Geophysical Survey Techniques to Offshore Geological Survey before the Drilling Engineering

随着我国经济的快速发展,对海洋资源的开发利用不断加强,浅海及海岸工程建设日益增多。在施工前,为确保工程安全,前期地质调查至关重要。地球物理探测作为一门综合性较强的探测技术,在海洋工程地质和海洋灾害地质调查中有着不可替代的作用。本文基于浅海油气钻井的需要,在钻井平台就位前,应用测深仪、旁侧声纳仪、浅层剖面仪,单道地震仪4种物探设备,对井场进行了地球物理详查。调查范围为预设井位周围1km^2的海域,共布设了24条地球物理调查测线,对井场的水深、海底地形、海底障碍物、层序结构等基础地质状况进行了探测和收集。调查结果表明:埋藏古河道、凹凸地和沙波等灾害地质因素在本区均有分布,这些地质因素将会导致地层沉积的不均匀性,对未来海上钻井工程的作业有着潜在的影响,在工程设计及实施过程中应给予高度重视。

Pre-geological survey is essentially important to marine engineering constructing and determines the safety of the offshore operation. In this paper, the overall geological information for the aimed area should be obtained before the drilling platform was in position, so as to avoi- ding the existing geo-hazards while drilling. To address the problem, an integrated marine geo- logical and geophysical survey was carried out by using echo sounding system, side-scan sonar system, sub-bottom profiling system and single channel and seismic streamer. The survey area was around a scheduled site in the South China Sea, at which a certain survey well was de- signed in advance, and covering an area of about 1 km2. 24 geophysical survey lines were designed in this survey, including 21 main lines and 3 tie lines. After the data processing and ana- lyzed, some potential geo-hazards, including a lot of sand waves, some patches and a paleo - river, were observed in the survey area. All of them might result in the inhomogeneous sinking of sediments and pose a serious threat to the coming offshore drilling, therefore, it should be paid more attentions on them.