Abstract: Based on conducting marine carbonated reservoir research on one exploration area in the Sichuan Basin, according to the characteristics of field seismic data, the factors resulting in amplitude distortion are analyzed. Combined with the OMEGA SPS (seismic processing system), research and development of key pre-stack image processing technologies with true amplitude are emphasized for application. Refraction tomographic static correction is applied to iterative correction of near surface models, aiming at reducing the difference between the travel time calculated and the first-arrival picking value and developing near surface models with high accuracy. So the problem of static correction caused by horizontal change of near surface velocity is solved. Non-surface consistent residual statics is applied to solve the problem of residual high-frequency statics caused by the outcrop of high-velocity layers. Nonlinear abnormal noise attenuation of separate frequency and time variation is applied to eliminate the noise with abnormal amplitude and frequency of shots,meanwhile, the relative amplitudes among effective signals will be not been changed. False pre-stack time image caused by heterogeneous offset distribution is wiped out based on the application of regularization technologies, so common imaging gathers and angle gathers with true amplitude are obtained. Through pre-stack amplitude-preserved processing, the relative amplitudes among pre-stack common imaging gathers are kept well in the studied area, the signal-to-noise ratio and resolution are improved greatly. Therefore, the amplitude near the target layers of calculated angle gathers feature in obvious variation. Pre-stack inversion and fine interpretation in marine carbonate gas reservoirs are fulfilled successfully.

Key words: pre-stack imaging, true amplitude, static correction, abnormal noise attenuation, pre-stack time migration, offset regularization