Using Joint Lithology-Elastic Inversion to Enhance Earth Model Building Workflows

Abstract

Summary Constraints can be imposed to a velocity model by rock physics modelling to capture key geological processes that shaped the present-day response of the subsurface. Lithology-dependent compaction trends can provide useful information on the expected range of velocities at different depths. The ability to model those compaction trends and to jointly estimate lithologies and velocities from seismic amplitudes with fully data-driven inversion approaches means that seismic reservoir characterization workflows can be incorporated in the earth model building process to improve imaging velocities. In this North Sea example, we demonstrate how litho-elastic inversion results, which use reflection amplitude- and lithology-driven compaction modelling, are used to update and provide initial low-frequency P- and S-wave velocity models for seismic imaging. The results revealed uplift in the P- and S-wave velocity model, stacked images, and gathers when the low-wavenumber velocities from joint litho-elastic inversion are incorporated into the earth model building workflow. The improvements of the earth model building workflow increase the likelihood of faster and more accurate convergence of subsequent tomographic iterations.