Progress report: Application of advanced materials/treatments for abandonment and mitigation

Work on materials and treatments for improving well integrity, and for mitigating any leaks that might occur, is funded at Utrecht University (UU), IF Technology / Well Engineering Partners (IFWEP), and TU Delft (TUD).

During Year 1 of CATO-2, preparatory work has been conducted at UU with the aim of identifying mineral additives to wellbore cements (or injection fluids) that can act as clogging agents upon reaction with CO2. Further preparatory work at UU has included assessing the geochemical and geomechanical effects of such reactions, and setting up equipment to study them. A variety of powdered minerals, such as olivine, serpentine and calcium hydroxide have been identified from the literature as potentially promising additives, alongside fly ash. Preliminary experiments performed on olivine and fly ash have also shown that reaction is rapid enough to be potentially useful and that significant reduction in permeability results. However, theoretical studies have indicated that the swelling that accompanies reaction can have both beneficial (clogging) and detrimental (fracturing) effects. Optimising clogging effects over fracturing will therefore be key to the work planned for Years 2-5.