Challenge
Safe well materials are a vital element in ensuring CO2 storage.
Solution
Testing confirmed the integrity of repurposed CO2 storage wells and guided the selection of corrosion-resistant materials
Result
With Welltec A/S, we assessed the corrosive effects of high-pressure CO2 and water on well materials with a customised test and protocol.
Ensuring the safety of CO2 storage wells required precise corrosion testing for material reliability, leading to the selection of corrosion-resistant materials and enhancing the wells' integrity.
Pragmatic underground CO2 storage solution is a piece of the green transition puzzle
Underground CO2 storage was aimed as a pragmatic solution to mitigate emissions from hard-to-abate sectors such as heavy industry, where immediate and complete decarbonisation is challenging. Repurposing existing underground wells in Stenlille, Gas Storage Denmark is developing CO2RYLUS, Denmark could become first onshore CO2 storage facility.
Lack of textbook well corrosion data required new test protocol
The corrosivity of supercritical CO2 and formation water depends on reservoir chemistry. Since no textbook corrosion data is available for a scenario like the one in Stenlille, we planned and performed a series of corrosion tests within the CCUS partnership with Welltec A/S to assess the potentially corrosive effects of high-pressure CO2 and formation water on steel materials.
Simulated conditions in injection and monitoring well provided actionable results
Specialists within geophysics, geology, well design, plant operation and corrosion joined forces at two workshops to design two tests that simulated the conditions in the injection well and a monitoring well. The test performed by the Welltec Test Flow Loop team was set to simulate a long-term exposure of injector well materials to a large amount of formation water and supercritical CO2 containing impurities.
The test performed by the Force Technology team examined the galvanic effects in the well packer design. In short, the tests showed lower corrosion rates than anticipated, though there were some concerns regarding carbon steel corrosion. Consequently, Gas Storage Denmark opted for highly alloyed materials for modifications.
