An Example of Adaptive Seismic Monitoring of CCS using the SEAM CO2 Model

Summary We present the development of an adaptive monitoring system based on a seismic methodology that is targeted, scalable, and responsive to the monitoring objectives of the project phase and identified risks. Using the SEAM CO2 model, we review how this system operates. The scenarios presented in the model demonstrate how the system responds for three potential results within a CO2 storage project, including the conformance case, a nonconformance case, and a noncontainment case. Using elastic finite element synthetic data derived from the model, this paper reviews the key steps and workflows of the system and shows how one would trigger the next level of monitoring. The key steps include a new quantitative risk analysis workflow, which uses a coupled geomechanical and flow simulation model to identify the probability and severity of subsurface risks. A novel technique called wavefield colouring is used to provide an early indication of divergence from model conformance before an adaptive, data-driven survey design process derives the required acquisition effort to quantify and mitigate the detected irregularity using 4D Full Waveform Inversion (FWI). The system is acquisition hardware agnostic but has been designed to leverage the benefits of the surface distributed acoustic sensing system (S-DAS).