Reflection seismics has become an important asset for mineral exploration in a hardrock environment. Recently published case studies clearly show the superiority of depth imaging over the standard time-domain imaging workflows in such context. While pre-stack depth migration has been a standard approach in the hydrocarbon exploration industry, it has only recently been adopted to imaging hardrock seismic data. One of the major obstacles for its wider adoption is the lack of robust velocity model building tools. Conventional reflection tomography fails if there are no coherent reflections to drive model updates. First-arrival tomography has been successfully used in many cases, but its resolution and depth penetration are inherently limited. In recent years, a new technique of velocity model building called full-waveform inversion (FWI) has helped the hydrocarbon industry to solve complex imaging challenges, e.g. seeing through gas clouds and resolving shallow velocity heterogeneities. FWI is bringing unprecedented resolution in elastic/anelastic parameter models as compared to ray-based methods.

In our webinar, we demonstrate the adoption of the 3D acoustic FWI technology to build high-resolution velocity model for improved imaging using 3D seismic data acquired over the Blötberget iron-ore deposit (Ludvika, Sweden). We show that the FWI velocity model itself can be an important interpretation asset.