Deliverable D4.5 – Old well state, Danish site
A vintage exploration well, Vedsted-1, is located on the Vedsted structure and could be a potential leakage point for a CO2 storage operation. The present deliverable summarizes a study completed to evaluate the present state of the well and possible mitigation actions to avoid leakage. Vedsted-1 well was drilled and abandoned in 1958.
Data collected about the well was compared to requirements from present regulations and from assessment of risks connected to CO2 storage.
The well was found not to be in line with current requirements for well abandonment. A well intervention is deemed necessary and different options are envisaged; the well could be reactivated to be used for monitoring and possibly as a back-up injector/producer; it could be plugged and abandoned, or an instrumented abandonment could be attempted.
The options that would minimize operational and functional risks are plug and abandonment or reactivation. The first option would cost around 180 k€ and the second one at least 3 times as much.
The final decision on whether to reactivate or abandon the well depends on different sets of criteria, reflecting opportunities as well as costs. At this point, the agreement is that proper plug and abandonment after well re-entry is the best option.