Natural Analogs for Geologic Storage of CO2: An Integrated Global Research Program

Coordinated research efforts are underway on three continents (North America, Europe, Australia) to study naturally occurring carbon dioxide deposits, in order to address fundamental questions and concerns about the long-term storage of CO2 in geologic formations. Natural accumulations of carbon dioxide exist in many geologic basins. Some deposits are stored in secure and impermeable traps, whereas others are unstable and leaking. These deposits provide unique “natural analogs” for the various options of storing CO2 in geologic formations, including injection of CO2 into depleted oil and gas fields and saline formations. Our research programs comprise an integrated analysis of the geologic, engineering, safety, and economic aspects of natural analogs. How long can CO2 be stored underground? What are the long-term effects of CO2 on reservoir and cap rock systems, and in particular what evidence exists for mineralogical changes indicating formation of stable minerals? If the CO2 leaks similarly to many hydrocarbon accumulations, where does it go, how fast and what are the effects both in the subsurface and at the surface? What reservoir screening methods can be developed to high-grade geologic sequestration candidate sites? What are the low-cost and safe engineering techniques already developed by the CO2 production industry that could be adapted for geologic storage? These and other fundamental issues will be evaluated to address scientific and public interest about the safety and efficacy of the geologic storage of CO2.