Wellbore

won't the CO2 escape via the injection well or existing wells?

Wells represent zones of potential leakage and therefore threaten the long-term efficiency and safety of a storage site. Wells are composed of compartments, including the casing, the cement sheet and cement plug. For a well to be ‘tight’ or impermeable, the boundaries or interfaces between these compartments must be perfectly leakproof, as must the interface between the well and its intersection with the caprock.

ULTimateCO2 is carrying out an innovative real-scale experiment in the underground rock laboratory of Mont Terri in Switzerland to reproduce the true conditions of a wellbore environment. The well bottom is then brought into contact with brine acidified by dissolved CO2 for over a year. Continuous monitoring of the permeability of the wellbore environment will enable a better understanding of the processes involved and therefore how to tackle this problem at true scale. Numerical modeling will help predict the flow paths of fluid migration and any geochemical alterations. Fluid-rock interactions within the different compartments will be characterized in the laboratory and, after more than a year of introducing CO2, the entire wellbore system will be extracted to enable detailed identification of any potential leakage paths and geochemical interactions at the interfaces. This is the first field experiment of its kind: reconstructing a well that intersects a shaly caprock and equipping the system with monitoring instruments to investigate the sealing capacity between wellbore interfaces.

Dernière mise à jour le 12.05.2014