Towards Improved Reservoir Characterization in Pre-Salt Carbonates with Integrated Elastic Full Wavefield Inversion

Summary Successful exploration and development in pre-salt carbonates in Brazil critically depend on differentiating net versus non-net. This differentiation is significantly challenging with narrow azimuth data with conventional imaging and reservoir characterization methods. The challenges mainly come from the geological complexity and inadequate data quality lacking azimuth and frequency content in the seismic data. Complex salt geometry generates illumination variability and elastic wave modes and scattering caused by strong property contrasts in the salt, carbonates and layered anhydrites cause complex transmission losses. In addition, thick reservoirs and non-reservoir units beneath the salt complicate the property estimation due to lack of low frequency contents. Beyond the data driven challenges, the elastic property contrasts within the available frequency bandwidth are intrinsically weak, which further lowers the signal content. In this paper, we demonstrate the application of integrated elastic FWI (eFWI) as a holistic physics driven solution to address both imaging and reservoir characterization problems. Our hypothesis is modeling both signal and noise via eFWI can be a possible path toward a robust solution in such environments. We further integrate our eFWI results with high resolution imaging stacks and rock physics priors via Bayesian integration framework to produce absolute band elastic properties.