As brines ascend from carbonated wells, any dissolved CO₂ will exolve; forming carbonic acid which can attack steel casings, tubing and process equipment.
In combination with the high temperatures typically encountered in geothermal environments, CO₂ contributes to the uniform corrosion of metal components. In laboratory simulations, low-alloy steels like AISI 4140 show baseline corrosion rates of 24.9 ± 37.1MMpy in highly-carbonated brines. But it’s important to remember that these rates can spike due to changes in pressure or temperature, rapidly reducing the lifespan of mission-critical infrastructure.
When these products are stripped away from casings and process equipment, erosion-corrosion effects intensify damage and can rapidly eat through casings or tubing.
Finally, research shows that carbonic acid can weaken well cements by diffusing into microcracks, and reacting with calcium hydroxide to destabilise the structure and integrity of cement, impacting the lifespan of geothermal wells.
While robust material selection can go some way towards mitigating CO₂ corrosion, experience has taught us that challenging environments - characterised by high temperatures, high CO₂ content and an unfavourable flow regime - require careful handling.
Drawing on over four decades of industry experience, we have developed a GeoHib; a unique corrosion inhibitor that’s ideally suited to the peculiarities of geothermal environments.
In conjunction with stringent laboratory testing and the input of our market-leading R&D team, GEOTECH 2 can be customised to suit the specific chemistry of your brine; allowing us to fine-tune for variables like chloride content, pH or flow rate. Our inhibitor products can be deployed alongside scale control systems and are designed for adaptive dose control.
By carefully monitoring conditions inside your well, we can adjust dose volumes to maintain optimal protection without overuse; improving operational efficiency, and protecting your well without putting unnecessary pressure on your maintenance budgets. As with all Roemex solutions, our focus is on deploying effective remediation that protects the long-term health of your geothermal project.