Microseismic imaging using rock physics-based full-waveform inversion

Microseismic imaging includes localization of micro-seismic events and characterization of their source mechanisms. The accuracy of the source localization is highly dependent on the (generally anisotropic) velocity model. Conventional methods for microseismic imaging are typically based on manual travel time picking in an approximate velocity model. However, more accurate results can potentially be obtained by making use of a larger portion of the microseismic data; that is, if one performs a full-waveform inversion (FWI). In this project, we focus on the development of scattering based approaches to microseismic FWI. We have already developed fast integral equation methods for frequency domain wavefield modeling acoustic and anisotropic elastic media with monopole, dipole and moment tensor sources (Shekhar et al., 2023). Also, we have developed matrix-free scattering approaches to multi-parameter FWI in acoustic and anisotropic elastic media for improved reconstruction of the background velocity model (Jakobsen et al., 2023). Currently, we are improving on existing methods for FWI in anisotropic elastic media by using different parameterizations of seismic anisotropy. Also, we have are developing methods for inversion of microseismic waveform data for the microseismic source location and moment tensor using based on a combination of global and local optimization methods (Eide, 2023).