3.4 Well integrity

Main objective

A well is a potential weak point where leakage may occur as this is the place were CO2 was injected. To prevent leakage as much as possible the well is plugged with cement on several places over a great distance. This plugging is common practice in oil en gas industry. However as CO2 can induce corrosion extra care needs to be taken.

In this work package several methods will be developed to monitor well integrity once the well is abandoned.

New quantitative insight into the site-specific chemical and mechanical degradation potential of the wellbore system (cement, steel, rock) at in-situ reservoir conditions will be gained by experimental testing and modelling.

For future projects new well design and work over strategies that ensure well integrity prior to abandonment will be developed. As well as the use of advanced materials will be looked upon.

The work package consists of three tasks:

Well integrity evaluation

Investigation of techno-economical feasibility of storage projects from the well perspective by assessing its current status.
Providing well design and work over strategies that ensure well integrity prior to abandonment.
Providing site-specific abandonment strategies and remediation/mitigation techniques that adequately ensure long term well integrity and secure containment of stored CO2.
Developing optimal protection of the wellbore system by application of advanced materials and (surface) treatments

Chemical and mechanical degradation: interaction of processes and materials

Gaining quantitative insight into the site-specific chemical and mechanical degradation potential of the wellbore system (cement, steel, rock) at in-situ reservoir conditions, by experimental testing and modelling.
Gaining insight into the interaction between chemical and mechanical processes relevant for wellbore integrity by experimental testing and modelling.

Monitoring well integrity

Developing (permanent) downhole sensor systems to verify of both short- and long-term well integrity.
Determining sensitivity of logging tools and permanent downhole sensors with respect to CO2 migration along (abandoned) boreholes.
Developing strategies to monitor inaccessible abandoned wells