南海北部地球物理科学考察航次在南海西北部西沙-中沙海域布设四条测线，其中L1、L2和L3测线进行OBS折射地震调查、多道反射地震调查和高分辨率浅地层剖面调查，以获取油气盆地浅部沉积层、盆地基底和深部地壳的结构特征，揭示该区油气资源的分布状况和资源潜力，推测深部构造与盆地演化的关系，进而探讨南海北部陆缘的构造属性和形成演化过程。L4测线进行水体反射地震和XBT调查，开展地震海洋学和南海西边界流研究。

The geophysical survey of the northern South China Sea (SCS) includes four profiles in the Xisha-Zhongsha water area of the northwest SCS. In this survey, Ocean Bottom Seismometer (OBS) survey, Multi-Channel Seismic (MCS) survey and high resolution sub-bottom profiling are designed along L1, L2 and L3 profiles. The purposes of these profiles are to obtain the detail structure of shallow sedimentary layers, the basement and the deep crust, to reveal the distribution and potential of oil/gas resource, and to infer the relations between deep structure and basin evoluton, and then to infer the tectonic nature and evolution of the continental margin of the northern SCS. Water body reflect seismic and XBT survey will be carried out along the L4 profile for the study of seismic oceanography and western boundary current of the SCS.