Dynamic modeling of geological carbon storage in aquifers – workflows and practices

Geological carbon storage (GCS), particularly within deep saline aquifers, is considered a promising and efficient approach for sequestering significant volumes of anthropogenic CO₂. Computational models play a crucial role in assessing the feasibility of GCS, as they contribute to risk assessment, delineation of area of review, short-term and long-term monitoring design, regulatory compliance, decision-making, project planning and optimization. Currently, there are numerous applications for Class VI permits with accompanied GCS modeling results with various levels of implementation of best practices that the industry and academia has developed over the past several years. It is, therefore, necessary to document the established practices, with the aim of creating a more unified approach for modeling CO₂ behavior in aquifers. This study provides an overview of practices and workflows for reservoir modeling, particularly focusing on CO₂ storage in saline aquifers, with a specific attention to the United States regulations, including those set by the Environmental Protection Agency (EPA). We focus on technical challenges and potential solutions for creating reasonably accurate and scientifically robust GCS dynamic models within aquifers, while considering factors like hydrodynamics, geology, thermophysics, geochemistry, and geomechanics. Our goal is to provide a valuable resource to both industry stakeholders and academic researchers, enhancing the understanding of GCS dynamic modeling implementations and directing future research and development efforts in line with Class VI permit objectives.