CO2 Storage Geoscience and Engineering

Reduction in global greenhouse gas emissions is a key challenge for modern society. Part of the solution is long-term storage of CO2 in deep geological formations. The main purpose of this book is to explain the concepts and technologies involved in geological CO2 storage. The material presented here was initially developed as university course notes (at NTNU) and later published under the successful title How to Store CO2 Underground: Insights from Early-Mover CCS Projects by Philip Ringrose. In this more substantial work, we build on those initial insights to provide a broader treatment of CO2 storage technology, with greater emphasis on geomechanics, injection, and monitoring. Bahman Bohloli joins Ringrose in this new work, bringing expertise in rock mechanics, formation testing, CO2 storage, gas storage, and geotechnical engineering. We have also expanded the coverage of geophysical and geochemical monitoring systems applied to CO2 storage projects. In this book, we summarize the essential components of Carbon Capture and Storage (CCS) projects, including transport systems and the underlying Earth science concepts. We then address the geomechanics of CO2 injection, focusing on how rock systems respond. Under the theme of CO2 storage geoscience, we review the main trapping mechanisms and explain how storage capacity is affected by flow dynamics, injectivity, pressure development, and geomechanical limits. Injectivity and storage containment are then considered in more detail, drawing on key concepts from geology, engineering, geomechanics, and geochemistry. We examine longer-term processes using evidence from laboratory and field studies and show how targeted monitoring tools can be used to verify that projects are progressing according to plan. In the final section, we explain how CO2 storage projects are designed, using examples from recent projects to illustrate how key technical decisions are made in practice. We then review the modelling methods used to forecast multiphase fluid flow and geomechanical responses. Using the latest portfolio of monitoring methods, including conventional seismic acquisition, passive seismic monitoring, and fibre-optic sensing, we show how short- and long-term storage assurance can be demonstrated with high confidence. We also connect CO2 storage technology to other forms of energy storage, including the cyclic storage of air, methane, and hydrogen.