The Research And Application Of Multiple Attenuation In Shallow Water By Wave Equation

Shallow water demultiple has always been a key problem in the seismic data processing.In shallow water environment,as the water depth is shallower,the period of multiple wave is shorter,so that multiple wave will seriously interfere with the recognition of primary wave.At present,the combination of SRME and predictive deconvolution is commonly used to suppress shallow water multiple in production,but it can't achieve the desired effect.Therefore,it is of great theoretical and practical significance to study a set of reasonable and efficient methods for attenuating shallow water multiple wave.Firstly,this paper elaborates the characteristic and identification methods of shallow water multiple wave,and focuses on the difficulty of shallow water de multiple.Secondly,based on the theory of wave equation,it researches the advantages and disadvantages of SRME and wavefield extension technique.Finally,in combination with actual marine seismic data processing,3D SRME technique based on CDP gathers is used to attenuate surface-related multiple wave and wavefield extension technique is used to attenuate seafloor-related multiple wave.The advantages of these two technology are fully exploited,which make the ideal suppression of shallow water multiple wave,and without damaging effective information.The innovation of this paper is to solve difficult problem which is surface related multiple attenuation in raised space or depression and seafloor related multiple attenuation in basement.in order to attenuate shallow water multiple,this paper use 3D SRME based on CDP gathers and 3D wavefield extension.Through the study of the attenuation effect of multiple wave in seismic data,a set of technical flow of shallow water demultiple is formed by wave equation theory in this paper.Firstly,the characteristic of multiple wave is analyzed.Then 3D SRME based on CDP gathers is used to suppress the surface-related multiple.Along sea floor of stacking profile,this paper picks up time and establishes an accurate water depth model by time-depth conversion.Finally,seafloor-related multiple is supressed by 3D wavefield extension technology.This technical processing flow can provide a theoretical basis and technical support for the study of shallow water demultiple.