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.

中文翻译：

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用于波形反演的地震散粒编码方案

可以在地震波形反演中使用散点编码技术，以减少反演过程中的地震模拟次数，从而显着降低计算成本。在这里，我们开发了两种替代的镜头编码方案来执行同时源波形反转。第一种方案（I）使用应用于地震道的随机相位旋转对镜头集进行编码。第二种方案（II）对具有随机静态时移的镜头集进行编码。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。第二方案是常规静态移位编码（IV）的变体，但是第二方案中的静态时移限于主频的一个周期。将所有编码的镜头集合起来，形成一个超级镜头集，以进行地震波形反演。我们在迭代反演中结合使用这些镜头编码方案和重新启动的L-BFGS算法来执行时域波形反演。有效性和效率分析表明，本文提出的两种镜头编码方案（I和II）可以改善迭代反演的收敛性，减少镜头之间的串扰效应，从而生成高分辨率的地下速度模型。