The Environmental Protection Agency recently finalized two guidance documents for Class VI wells used for long-term carbon capture and sequestration (CCS): the Underground Injection Control (UIC) Program Class VI Well Area of Review Evaluation and Corrective Action Guidance and the Underground Injection Control (UIC) Program Class VI Well Site Characterization Guidance. EPA also released a draft guidance entitled Draft Underground Injection Control (UIC) Program Guidance on Class VI Well Plugging, Post-Injection Site Care, and Site Closure.
- The Class VI Rule requires owners or operators of Class VI injection wells to delineate the area of review (AoR) for the proposed Class VI well, which is the region surrounding the proposed well where underground sources of drinking water may be endangered by the injection activity. 40 C.F.R. 146.84.
- The Guidance provides information regarding modeling requirements and recommendations for delineating the AoR, describes the circumstances under which the AoR is to be reevaluated, and describes how to perform an AoR reevaluation. The Guidance also presents information on how to identify, evaluate, and perform corrective action on artificial penetrations located within the AoR.
- The Class VI Rule establishes minimum criteria for the siting of Class VI wells. Class VI wells must be located in areas with a suitable geologic system, and owners/operators must perform detailed site characterization and submit extensive geologic data to the UIC Program Director. 40 C.F.R. 146.83, 146.82(a).
- The Guidance describes the data needs, process, and procedures for conducting a geologic assessment that meets the requirements of the Class VI Rule. It also provides guidance on the types of information to collect and submit with a Class VI injection well permit application and where and how such information might be obtained. The Guidance also provides considerations for determining when issuing a Class VI permit is or might not be appropriate, or when more data may be needed to make a determination regarding site suitability.
- The Class VI rule requires that, following the cessation of injection, owners/operators properly plug their injection wells, monitor the site, and close the site. 40 C.F.R. 146.92, 146.93. The Guidance provides technical guidelines for well plugging, post-injection site care monitoring, and site closure.