Abstract：Due to the presence of the Neogene unconsolidated clastics with high porosity and complex fault systems, absorption and attenuation to seismic signals is very strong, resulting in serious attenuation of high-frequency energy and poor amplitude-preserved property of pre-stack gathers in the Bohai Bay Basin. Specifically, the AVO responses of pre-stack gathers are consistent with the corresponding synthetics at low frequency, but not at high frequency, so that the pre-stack hydrocarbon detection techniques based on AVO response cannot be effective. An AVO response correction method in time-frequency-space domain is proposed. It is constrained by low-frequency components, and combines high-resolution time-frequency analysis technology. Following the AVO trend, the method takes better low-frequency energy as a reference, and builds a data-driven three-dimensional time-frequency-space-domain correction factor according to the relationship between the AVO response trend of pre-stack gathers at low frequency and pre-stack gathers at other frequency. The correction factor can make up for the influence of the high-frequency attenuation difference between far and near offsets on AVO analysis, and effectively improve the AVO amplitude-preserved property of pre-stack gathers. Applications to synthetic data and actual data show that the AVO response correction method we proposed can restore the real AVO law of pre-stack gathers and provide reliable basic data for the application of pre-stack hydrocarbon detection methods in Bohai Oilfield.
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