Abstract：Based on strong adaptability of wave-equation finite-difference depth migration to vertical and lateral changes of medium velocity,the paper presented a one-way wave-equation pre-stack depth migration operator with optimal series.Based on continuation calculation of finite-difference wave-field,it adds compensation correction aimed at operator errors,so that improves imaging precision of operator;meanwhile can basically eliminate dispersion of difference scheme and improve signal-to-noise ratio of imaging section.The operator is characterized by low-order equation,imaging for steep dip and adapting for any changes in velocity field.Because all calculation in the paper is in frequency domain,the method has an advantages of high computational efficiency and imaging easily by comparison with finite-difference algorithm in time domain.Impulse response test and results of pre-stack depth migration for Marmousi model show that the migration method is effective tool for "Three High" (high resolution,high signal-to-noise ratio and hifi) seismic data processing in strong lateral varying velocity media.
