Geological Carbon Sequestration: Ensuring the Integrity of Class VI Injection Wells

Geological carbon sequestration, a crucial strategy in mitigating climate change, involves injecting carbon dioxide (CO2) deep into underground rock formations to trap it and prevent its release into the atmosphere. A key component of this process is the construction and monitoring of Class VI injection wells, which require stringent requirements to ensure public health and safety.

To guarantee the integrity of these injection wells, several testing and monitoring requirements must be met throughout the project's life cycle, including after CO2 injection has ceased. This involves tracking groundwater quality, the movement of the CO2 plume and pressure front, and the integrity of the injection well itself.

Well construction is a critical aspect of geological carbon sequestration. The Class VI injection well must be built in a manner that prevents any leakage of CO2 outside of the designated injection zone. This requires careful site characterization to ensure that the geology in the project area can receive and contain the CO2 within the injection zone.

Computational modeling is also essential for predicting the extent of the injected CO2 plume and associated pressure front, as well as identifying and addressing any deficiencies in existing wells within the Area of Review. This helps to mitigate the risk of induced seismicity and ensures that public health and Underground Sources of Drinking Water (USDWs) are protected.

The UIC Program, authorized by the Safe Drinking Water Act (SDWA), regulates the injection of fluids into underground rock formations for storage or disposal. Class VI wells, one of six classes of injection wells under this program, are specifically designed to protect public health and USDWs from the unique nature of CO2 injection for geological carbon sequestration.

In conclusion, geological carbon sequestration relies heavily on the proper construction and monitoring of Class VI injection wells. By adhering to stringent testing and monitoring requirements, well construction standards, site characterization guidelines, and computational modeling protocols, we can ensure that this critical technology is implemented safely and effectively, ultimately mitigating climate change while protecting public health and USDWs.