天然气水合物勘探中OBS资料地震干涉法技术

OBS data seismic interferometry technique in gas hydrate exploration

OBS(ocean bottom seismometer,海底地震仪)勘探主要应用于天然气水合物的勘探和识别。由于在实际勘探中,尤其是在深水区域,震源和OBS之间存在高度差异,因此OBS数据无法使用常规方法进行处理成像。地震干涉法是对两个检波器接收到的信号进行互相关运算,得到炮检点均位于同一平面内新的虚源记录,在处理虚源记录时可以使用陆地速度分析的方法得到速度信息,并且该方法在处理数据时,可同时使用直达波和多次波进行处理,具有充分利用波场信息的特点。本文将地震干涉法引入OBS数据成像处理中,实际OBS资料数据处理结果显示,该方法得到的结果其成像精度高于多次波镜像偏移,而且本文方法更具处理效率优势。

Ocean bottom seismometer(OBS)exploration is mainly used to identify and characterize natural gas hydrates.However,the significant elevation difference between the source and OBS,particularly in deep water environments,prevents OBS conventional imaging methods from being directly applied to OBS data.This paper proposes a new seismic interferometry approach to overcome this challenge.By crosscorrelating signals received by two OBS detectors,a virtual source record is generated.This record can then be processed using conventional land velocity analysis techniques to extract velocity information.A key advantage of this method is its ability to use both direct waves and multiples for data processing,maximizing the utilization of available wavefield information.Results from processing actual OBS data demonstrate that the imaging accuracy achieved with this seismic interferometry method surpasses that of conventional multiple image migration techniques.Furthermore,the proposed method offers improved processing efficiency.