A Near Seafloor Modelling Study and a Multicomponent Vz Denoising Application

Data recorded on the seafloor using either ocean bottom cable (OBC) or ocean bottom node (OBN) is normally comprised of one hydrophone and three geophones or accelerometers components. Pressure and particle velocities/accelerations are recorded with a broader bandwidth than streamer acquisition data due to a quieter recording environment that is closer or coupled to the seabed. In addition, such data acquisition methods have been widely employed to achieve significant signal-to-noise (SNR) enhancement by combining the hydrophone and vertical geophone components. Especially, the application which is called PZ summation can effectively suppress receiver side ghost and surface-related multiples. There is a variety of seafloor generated noise on the vertical geophone that hinders successful PZ processing, such as, bad sensor coupling with the seafloor, Scholte waves, backscattering noise and converted shear waves. Particularly, scattering noise generated by very near to the seafloor scaterrers exhibit random seismic signatures in the common shot domain while becoming strong and coherent noise trends in the common receiver domain. Hence, the success of PZ summation is heavily depended on the pre-conditioning and denoising of the vertical geophone component.