Efficient Boundary Storage Strategy for Three-Dimensional Elastic Full-Waveform Inversion in Time Domain

Zhang, Qingchen (China University of Petroleum) | Zhou, Hui (China University of Petroleum) | Wang, Jie (SINOPEC Geophysical Research Institute) | Zuo, Anxin (China University of Petroleum) | Xia, Muming (China University of Petroleum)

OnePetro 

Summary

Due to the gradient calculation requiring cross-correlation of the forward wavefields and back-propagated residual wavefields at each time step, the great storage amount becomes an obstacle of practical application of full-waveform inversion, especially in three-dimensional elastic case in time domain. In this paper we extend the efficient boundary storage to the time domain three-dimensional elastic full-waveform inversion on multi-GPU. Based on the efficient boundary storage strategy, the storage amount can be reduced dramatically. As a result, we can save the partial forward wavefields directly on the GPU memory and reconstruct the full forward wavefields synchronized with back-propagated residual wavefields along the reverse time direction. This strategy avoids frequent CPU-to-GPU or GPU-to-CPU memory copy (extremely time-consuming) at the cost of the recomputation (little time-consuming) of the forward wavefields. Our forward simulation tests show that the GPU’s supercomputing effect can be fully exploited with this strategy. In addition, we perform a three-parameter simultaneous inversion of P-, S-wave velocities and density. The favorable inversion results verify that our algorithm is feasible and efficient.