A physical model study of shale seismic responses and anisotropic inversion

The seismic responses of the shale properties are critical for shale gas reservoir evaluation and pro-duction. It has been widely reported that the clay minerals have substantial influences on the seismic wave anisotropy and brittleness. Hence, knowing the seismic responses of the clay-rich shales and estimation of shale elastic properties are significant for the shale gas industry. A physical model con-taining two groups of shale blocks as the target formations is constructed in laboratory. The group S contains six shale blocks with different clay contents, and the group N contains six shale blocks with different porosity. The acquired 2D seismic data is used to analyze the seismic responses of two corre-sponding seismic lines. An anisotropic three-term inversion method is applied to one of the seismic inline to estimate the elastic properties the target shale blocks. The inversed attributes can be used to reveal the effects of shale clay contents. This study shows the substantial significance of using a physical model to observe the seismic responses of shale properties. The inversion results indicate that the anisotropic three-term inversion method could provide accurate results of elastic properties as well as the P-wave anisotropy parameter for shale formations. (c) 2021 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Automated summary

This study demonstrates the importance of using a physical model to observe the seismic responses of shale properties, showing that clay content has a significant impact on rock elastic properties. By analyzing seismic data and applying inversion methods, accurate estimates of elastic properties and anisotropy parameters for shale formations can be obtained.