Improving wellbore seal integrity in CO2 injection wells

Work on Carbon Sequestration in subterranean formations has renewed interest in investigating the long term effects of CO2 on Portland cements. Portland cement will react with the injected CO2, and while recent research indicates these conventional cements are not a concern, additional work is ongoing to further improve the long term effectiveness of the wellbore sealant. This paper discusses various solutions to the challenges of selecting a proper wellbore sealant for a CO2 injection well. Additionally, the paper reviews the available sealant technologies, their application, and includes a discussion of stress modelling for these wells. A brief case history review of the design considerations for two high-rate acid gas injection wells in Wyoming is discussed. (C) 2009 Elsevier Ltd. All rights reserved.