Full waveform inversion (FWI) plays a major role in the oil and gas industry as a state-of-the-art technique that produces quantitative subsurface structures with high-fidelity images. Various FWI studies have been conducted, and these suggest that FWI is a promising inversion method. Recently, many attempts have been made toward three-dimensional (3D) and four-dimensional FWI applications (which were difficult to perform in the past) because of the progress made in computer science and the growth of computer resources. To manage the very large data requirement of 3D problems, a time-domain FWI that is relatively efficient in terms of memory demands must be implemented. However, it could encounter practical issues, leading to failure in its convergence. In this paper, we introduce these practical issues and several alternative methods for mitigating them. The first issue is the bandpass filtering of the observed seismograms. We suggest that the frequency-domain filter based on a reference wavelet would be optimal in terms of both bandpass filtering and source wavelet estimation. The second issue is related to acoustic approximation. We show that a simple density model comprising only water and solid layers is a reasonable option to address seafloor reflectivity properly. The last issue is the accumulation of round-off errors due to the massive computation of the objective function. We demonstrate that a simple modification of the error calculation can resolve this round-off error problem.

全波形反演 (FWI) 作为一种最先进的技术，在石油和天然气行业中发挥着重要作用，可生成具有高保真图像的定量地下结构。已经进行了各种 FWI 研究，这些研究表明 FWI 是一种很有前途的反演方法。最近，由于计算机科学的进步和计算机资源的增长，已经对三维（3D）和四维 FWI 应用（过去很难执行）进行了许多尝试。为了管理 3D 问题的非常大的数据需求，必须实施在内存需求方面相对有效的时域 FWI。但是，它可能会遇到实际问题，导致其收敛失败。在本文中，我们介绍了这些实际问题以及缓解这些问题的几种替代方法。第一个问题是观测地震图的带通滤波。我们建议基于参考小波的频域滤波器在带通滤波和源小波估计方面都是最佳的。第二个问题与声学近似有关。我们表明，仅包含水和固体层的简单密度模型是正确解决海底反射率的合理选择。最后一个问题是由于目标函数的大量计算导致舍入误差的累积。我们证明了对误差计算的简单修改可以解决这个舍入误差问题。我们建议基于参考小波的频域滤波器在带通滤波和源小波估计方面都是最佳的。第二个问题与声学近似有关。我们表明，仅包含水和固体层的简单密度模型是正确解决海底反射率的合理选择。最后一个问题是由于目标函数的大量计算导致舍入误差的累积。我们证明了对误差计算的简单修改可以解决这个舍入误差问题。我们建议基于参考小波的频域滤波器在带通滤波和源小波估计方面都是最佳的。第二个问题与声学近似有关。我们表明，仅包含水和固体层的简单密度模型是正确解决海底反射率的合理选择。最后一个问题是由于目标函数的大量计算导致舍入误差的累积。我们证明了对误差计算的简单修改可以解决这个舍入误差问题。我们表明，仅包含水和固体层的简单密度模型是正确解决海底反射率的合理选择。最后一个问题是由于目标函数的大量计算导致舍入误差的累积。我们证明了对误差计算的简单修改可以解决这个舍入误差问题。我们表明，仅包含水和固体层的简单密度模型是正确解决海底反射率的合理选择。最后一个问题是由于目标函数的大量计算导致舍入误差的累积。我们证明了对误差计算的简单修改可以解决这个舍入误差问题。