基于粒子群优化和保幅成像条件的广义屏偏移

Generalized screen propagator migration based on particle swarm optimization and amplitude-preserved imaging conditions

面对与日俱增的复杂构造和岩性的勘探需求,传统单程波偏移方法在成像精度和振幅保真方面都明显不足。本文从传统保幅单程声波方程入手,首先利用粒子群算法对广义屏算子中垂直波数展开式系数项做全局最优化处理,提高其对陡倾地层的成像精度;其次利用高斯窗函数优化反褶积成像条件,在确保振幅保真效果的同时也提高了其计算的稳定性。对模型试算和实际地震资料的应用表明,该基于粒子群优化和保幅成像条件的高阶广义屏偏移算法既能较好地适应复杂构造成像,还能有效提高地震波振幅保真能力,取得了良好偏移成像效果。

For identifying more and more complex structures,conventional one-way wave migrations are obviously inadequate in terms of imaging accuracy and amplitude preservation.To solve this problem we propose in this paper a generalized screen propagator migration based on particle swarm optimization and amplitude-preserved imaging conditions.First,on the basis of conventional amplitude-preserved acoustic wave equation,aparticle swarm optimization is used to perform the global optimal coefficients of vertical wave number expansion in the generalized screen propagator,and to improve its imaging accuracy for steep dip strata.Then a Gaussian-window function optimization is used to optimize deconvolution imaging conditions to ensure both the amplitude preservation and the calculation stability.Model trials and seismic data applications show that the proposed migration can not only improve the complex structure imaging,but also reduce the amplitude attenuation in strata.