On the detectability of CO2 plumes with seismic records: a numerical simulation study on the Otway case

Overview & Synopsis

One of the prevailing questions on the monitoring of CO2 plumes in a CCUS project is the detectability of changes in petrophysical and geophysical properties induced by the substitution of initial fluids by CO2 . Numerous works on the field data (Ghaderi et al., 2009; Landrø et al., 2017) have shown encouraging results on the ability of seismic attributes to detect and monitor changes in petrophysical properties, which can be linked with the geophysical properties through Petro-Elastic Models. Seismic attributes are also believed to have the potential for tracking straightforwardly changes in geophysical properties such as the elastic wave velocities (Landrø et al., 2004), on which we present the simulation results on the 3D Otway (Pevzner et al., 2021) case study conducted within project-team Makutu Inria and TotalEnergies.The numerical case study features a baseline and a monitor as geophysical models, with geophones and fibre optics (DAS) as receivers in a Vertical Seismic Profile (VSP) configuration. The wave propagation simulations are run on the GEOS platform featuring GPU accelerations. We aim at constructing a reliable and efficient numerical tool for precise simulations. Numerically we will show the impact of adaptative meshes on both the performance and precision; in terms of geophysical settings, we will illustrate the need of considering attenuation (Trinh et al., 2019) to match reference or real data. Finally we will compare the synthetic VSP records from DAS and geophones for the purpose of discussing the CO2 plume detectability.