CO2 Sequestration Wells - The Lifetime Integrity Challenge

Abstract

Abstract The technical challenges of CO2 injection wells are highly dependent on the individual well design parameters, principally the formation being injected into (saline aquifer versus depleted gas formation) and the quality (impurity levels) found in the CO2 source gas. These factors will impact the potential corrosion and other material degradation challenges which may threaten the well components including injection tubing, injection casing, cement and packer materials. The long term integrity of these components is critical to the injection phase of the life and the suspension and abandonment phases (depending upon the strategy selected for well abandonment). A key part of the acceptance of CO2 sequestration as a safe and reliable greenhouse gas control mechanism will be the proof that the well is truly leak-free. This integrity management element requires a comprehensive monitoring and pro-active warning system which highlights developing integrity issues before they become acute. Key well parameters requiring daily monitoring and intermittent testing have to be identified developed from industry international standards and regulations. Continuous well condition monitoring will require a dedicated well integrity software system which can integrate all relevant data from multiple sources. Data must be continuously automatically analysed using the software with developing well integrity problems identified and alerted to the operators before conditions become critical. Such a software has been recently deployed in gas storage wells and can be customized to CO2 sequestration wells.