中文摘要：

四分量海底地震仪（OBS）是一种新的接收仪器，其获得的地震数据信息量大，整体信噪比较高，频率成分丰富，具有较高的使用价值。OBS用于研究深部地壳结构已取得较好进展，但较少应用到油气勘探和盆地研究中。在南海西北部采用大容量气枪阵列（0.083m3）作为震源、利用OBS记录气枪震源的反射和折射信息，在油气勘探中是一种新的尝试。为正确使用OBS地震资料，必须采用不同于常规地震资料处理的方法，文中开拓性地使用了镜像叠前时间偏移处理方法。镜像叠前时间偏移处理方法是利用海面多次波进行成像的技术，包括OBS资料矢量保真处理、P分量（压力分量）和Z分量（垂直分量）的叠前处理和镜像叠前时间偏移处理等；其中矢量保真处理主要进行检波点位置二次重定位和检波点方向重定位及倾角校正， P、Z分量的叠前处理包括零相位化处理与地震道修改， P、Z矢量合并（P and Z summation）、剩余静校正、镜像叠加和多次波衰减等。采用镜像叠前时间偏移处理方法获得的剖面获得了较好的成像效果。

英文摘要：

The four component ocean bottom seismometer （OBS） is a new instrument. The seismic data obtained from the OBS contains a large amount of information; it has high SNR （signal-to-noise ratio） and abundant frequency compared to streamer data. The study of deep crustal structure has achieved good progress using OBS data, but the studies of oil-gas exploration and basin structure have achieved less progress. Using large capacity air-gun array （0.083 m3） as source in the northwestern South China Sea, we obtained seismic information from reflection and refraction data from the OBS, and then interpreted it for oil-gas exploration in an attempt. To properly use the OBS seismic data, we must adopt the method that is different from conventional seismic data processing method, in this paper we proposed a new method which used the method of mirror time migration of pre-stack processing. The method includes the OBS data vector fidelity processing, the P （pressure） and Z （vertical） component of the pre-stack processing and image of pre-stack time migration processing; the vector fidelity processing is to control and correct the positioning in space （x, y, z） and in time （clock drift）, and the geophone sensor orientation （vertical and horizontal components）; the P and Z component of the pre-stack processing includes zero phase processing and seismic- channel correcting, P and Z summation, residual static correction, image superposition and multiple attenuation; mirroring the pre-stack time migration processing is to use the multiple wave imaging technology. Using the mirror of pre-stack time migration processing, good imaging profile can be obtained.