OBS data seismic interferometry technique in gas hydrate exploration
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 cross-correlating 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.