Marine Deghosting Using the Continuous Wavelet Transform

The seismic bandwidth and resolution of conventional marine streamer data can be easily compromised by the appearance of a well know interference phenomena produced by the towing of sources and receivers below the water. A secondary signal, which bounces off of the sea surface near the sources and receivers, called a ghost signal, is very close to the original primary signals causing an interference pattern that distorts the wavelet. The interference manifests itself as a series of notches in the amplitude spectrum. The appearance of these notches narrows the bandwidth of the usable data and reduces the resolution of the seismic signal. We propose a new processing approach for deghosting the data based on a filtering algorithm applied in the Continuous Wavelet Transform (CWT) domain. The CWT provides a solid mathematical framework for dealing with the non-stationary nature of seismic data, by allowing a time variant analysis for the filter design and application. The application of the procedure on two different data sets demonstrates that our new deghost technique successfully eliminates the ghost notches and enhances the high and low frequencies, hence expanding the bandwidth and increasing the resolution of the data.