Undulating sea surface influence on reflection seismic responses

In order to truly simulate undulating sea surface influence on reflection seismic responses, a moderate calm sea surface undulation model (2m wave height) is built with the wave spectrum calculation model proposed by Wen Shengchang et al. Considering both accuracy and computational efficiency, we use the unequal distance difference scheme based on the ghost point extrapolation. Through the numerical simulation of simple layered model and Marmousi model, the following conclusions are obtained: ①The ghost wave and the primary reflection interferes irregularly under the influence of the undulating sea surface, resulting in different reflection seismic responses; ②The phenomenon of "jitter" of seismic reflection from the undulating sea surface occurs at all times, and is related to the undulating shape of the sea surface; ③Due to uneven illuminations of secondary reflection and irregular interferences of primary reflection, an uneven spatial distribution of seismic reflection energy affects greatly travel time, waveform, amplitude, spectrum, phase and bandwidth of direct and reflected waves, and causes a series of practical problems, such as poor ghost suppression, low signal-to-noise ratio, low resolution and local inversion non-convergence. © 2019, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.