Quest CCS facility: Halite damage and injectivity remediation in CO2 injection wells

The Quest CCS facility (located in Alberta, Canada) is a fully integrated carbon capture, transport and storage facility operated by Shell Canada. It continuously captures and stores about 1.1Mt of CO2 per year. While the initial injectivity for the Quest CO2 injection wells was very high, significant injectivity reductions have been observed. As dry CO2 is injected, water can evaporate from the brine into the CO2 driving precipitation of halite. Plugging of the perforation tunnel and pore throats in the near wellbore area can cause injectivity damage. One method to remediate halite damage is to inject a water-based fluid to dissolve the halite precipitate. Quest performed the first halite remediation treatment on one of the CO2 injector wells in 2020. The objective of this paper is to present the design, execution and results of this initial halite remediation treatment. An outline of the design of the halite remediation treatment will be provided. Subsequently the halite remediation treatment as executed in the field will be reviewed including the timing of operations and the pumping pressure and rate data. Finally, to evaluate the effectiveness of the treatment, skin analysis and injectivity trends pre and post remediation treatment shall be presented.