Attenuation of Marine Coherent Noise – A Processing Case History in the East China Sea

Abstract In some areas of the world, it is often not possible to collect marine seismic data free of additive noise origination from nearby sources such as offshore platforms or other ships. Conventional processes such as F-K filtering. Band-pass filtering, or CDP stacking are often ineffective at satisfactorily removing the coherent noise from the records. An effective solution is to randomize the coherent noise by gathering the traces into offset or receiver organized records followed by the application of an F-K prediction filter technique. This technique discriminates against random noise, removing it from the record but leaving the desired signal intact. Following the application of the F-X prediction step, the data are gathered back into shot organized records and processing continues with much improved signal to noise ratio. Applying this process before deconvolution proved to be a powerful method of improving the estimate of the source wavelet. The method is not limited to specific stages in the processing sequence, however. It can be applied either before or after stack or at any point where random noise exists.