Seismic shot-encoding schemes for waveform inversion
Seismic shot-encoding schemes for waveform inversion
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DOI：
10.1093/jge/gxaa051
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发表时间：
2020-08
影响因子：
1.4
通讯作者：
E. Duarte;C. D. da Costa;J. M. de Araújo;Yanghua Wang;Y. Rao
中科院分区：
文献类型：
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作者：
E. Duarte;C. D. da Costa;J. M. de Araújo;Yanghua Wang;Y. Rao
炮点编码技术可用于地震波形反演，通过减少反演过程中的地震模拟次数来显著降低计算成本。在这里，我们开发了两种可供选择的激发编码方案来执行同时震源波形反转。第一种方案(I)对应用于地震道的随机相位旋转的炮集进行编码。第二种方案(II)用随机静态时移对炮集进行编码。众所周知的极性编码方案(III)只是随机相位旋转方案的特例。第二方案是传统静态移位编码(IV)的变体，但是第二方案中的静态时间移位被限制在主频的一个周期内。将所有编码的炮集叠加成一个超炮点道集，用于地震波形反演。在迭代反演中，我们结合重启的L-BFGS算法，使用这些炮点编码方案进行了时间域波形反演。有效性和效率分析表明，本文提出的两种炮点编码方案(I和II)可以改善迭代反演的收敛，减小炮点间的串扰影响，从而得到高分辨率的地下速度模型。
A shot-encoding technique can be used in seismic waveform inversion to significantly reduce the computational cost by reducing the number of seismic simulations in the inversion procedure. Here we developed two alternative shot-encoding schemes to perform simultaneous-sources waveform inversion. The first scheme (I) encodes shot gathers with random-phase rotations applied to seismic traces. The second scheme (II) encodes shot gathers with random static time shifts. The well-known polarity encoding scheme (III) is just a special case of the random-phase rotation scheme. The second scheme is a variation of the conventional static shift encoding (IV), but the static time shifts in the second scheme are limited to one period of the dominant frequency. All encoded shot gathers are added up into a single super-shot gather for seismic waveform inversion. We perform the time-domain waveform inversion, using these shot-encoding schemes in conjunction with a restarted L-BFGS algorithm in the iterative inversion. The effectiveness and efficiency analyses demonstrate that the two shot-encoding schemes (I and II) proposed in this paper may improve the convergence of the iterative inversion, reduce the crosstalk effect among shots and consequently produce a subsurface velocity model with a high resolution.