Integrated inversion of seismic and mCSEM data for the estimation of petro-physical parameters

Abstract

Petro-physical parameters, such as porosity and fluid (water, oil, and/or gas) saturation, which provide useful information for reservoir characterization, can be estimated by a rock physics model (RPM) using seismic velocity and electrical resistivity from geophysical surveys. In this study, we have developed an effective integrated inversion of seismic and marine controlled-source electromagnetic (mCSEM) data for the accurate estimation of petro-physical parameters. First, to improve the resolution of the resistivity images from mCSEM inversion, we introduce a seismic-constrained mCSEM inversion using a cross-gradient constraint between seismic velocity obtained by seismic full-waveform inversion (FWI) and resistivity. Next, to reliably estimate the petro-physical parameters from the seismic and mCSEM inversion results, we suggest an integrated estimation approach which applies the grid-search method to the RPM. In numerical experiments with SEAM phase I model containing a salt-dome and several oil reservoirs, we can reliably estimate porosity and fluid saturation of upper reservoirs.