琼东南海域OBS纵波资料成像处理关键技术

The key technique of OBS p-wave imaging processing in Qiongdongnan area

OBS采集具有站点少、站点间距大,同时包含纵、横波信息的特点,因此,对OBS进行成像处理相对常规海洋地震资料处理而言具有更多的挑战。本文主要针对OBS纵波资料处理中几个关键处理技术:(1)利用直达波进行重定位处理获得准确的OBS位置,为OBS资料正确成像打下坚实基础;(2)利用水、陆检数据标定获得频率、振幅、相位一致的水检、陆检数据,并进行水、陆检合并处理;(3)通过波场分离有效地分离出上行波场和下行波场数据,利用具有更宽照明范围的OBS下行波场数据进行镜像偏移处理等。最终可获得海底及海底以下成像分辨率高、构造成像清晰、偏移归位准确的OBS纵波剖面数据。该成像数据频带宽,具有丰富的低、中、高频信息,能为后续的水合物无井岩性处理提供具有丰富频率信息的地震叠加资料。

The OBS data acquisition has the advantages of less receiver and longer distance between receivers and thus may receive both the press wave and shear wave at the same time.As far as imaging processing is concerned,OBS faces more challenges comparing to the conventional seismic data processing.This article focuses on the OBS p-wave data processing as follows.1.Direct wave is used for OBS reposition to ensure the correctness of location and to lay a solid foundation for correct OBS imaging;2.P component and z component are used for demarcating to make the two component data consistent on frequency,amplitude and phase for merging processing;3.through the analysis of wave field to effectively separate upgoing and downgoing wave field data and use the wider range of imaging＇s downgoing data to do the mirror migration.Finally we can obtain OBS p-wave profiles with clear sea bottom imaging,high resolution imaging below the sea bottom,and more accurate images in migration position.The final section has wide frequency band,rich frequency information,and can provide a lithological interpretation of a hydrate layer without well with rich frequency information of stacked seismic data.