The Research Of Seismic Data Processing Methods For Gas Hydrate Reflection At Mohe Basin

Mohe basin is located in the northern end of the greater hinggan mountains in northeast China,with the surface large undulation,the underground geological structure is very complex.The shallow permafrost regions at Mohe basin has the similar geological,geographical conditions with the Muli area in Qilian mountain where has found the gas hydrates,through in the area,geophysical survey work aimed at frozen soil depth has been carried out very much,the seismic method applied in permafrost regions for gas hydrates exploration and research at Mohe basin for the first time.Therefore,this research includes gas hydrate seismic exploration data processing at Mohe basin and a series of results are obtained.First,having an analysis,summary on the research status of natural gas hydrate and the Mohe basin in China,pointing out that at present,problems still existing in seismic exploration of natural gas hydrate in our country,putting forward the preliminary method for the data processing combined with the characteristics of seismic data in the study.Then,carry out a large number of experiments in view of the problem of static correction of seismic data.providing the most basic conditions for the later data processing.According to the shallow depth of the permafrost,the shallow low effective reflection folds of the seismic data,the low signal noise ratio(S/N),the subtracting method in prediction filtering denoising,the surface consistent deconvolution and series multi-step predictive deconvolution,Prestack denoising quasi three-dimensional RNA methods are adopted in prestack time domain and have effectively improved the signal-to-noise ratio of shallow data.Not only keep the data of wide frequency band,but also effectively highlight the shallow reflection,the shallow layer stack and migration profile with better effect.Finally,summarized the experience in data processing,makes a preliminary interpretation of the seismic profile,providing geophysical references for later gas hydrate investigation at Mohe basin regions.