Modeling of acoustoelastic borehole waves subjected to tectonic stress with formation anisotropy and borehole deviation

Sonic logging is a useful technique to estimate tectonic stress around a borehole. The key to successful evaluation of tectonic stress is having a thorough understanding of a forward model that generates responses of borehole waves to tectonic stress. We have developed a generic model to simulate responses of borehole waves to tectonic stress based on the semianalytical finite-element method and acoustoelasticity. This model can compute the distribution of tectonic stress around an inclined borehole with an arbitrary anisotropic formation and simulate the acoustoelasticities of borehole waves under this complicated stress. To avoid tedious and time-consuming code development, we also provide easy access to the model by reformulating and implementing the governing equations in a commercial software package. We validate the model by using three case studies in which analytical/numerical solutions are available, showing a good agreement between the results from our model and the solutions in the literature. We then apply the model to some important applications in boreholes, demonstrating that this model can provide a powerful tool for understanding the responses of borehole waves to tectonic stress.Agency for Science, Technology and Research (A*STAR)P. Zuo and Z. Fan are grateful for the financial support from A*STAR Science and Engineering Research Council under AME individual research grant 2018 grant call (project no. A1983c0030). Y. Liu was supported in part by the National Science Foundation of China under contract no. 61773283 and in part by the National Key R&D Program of China under contract no. 2018YFC0808600