Geologic Sequestration

As concern grows over the effects of rising CO2 levels in Earth’s atmosphere, governments and private industry are exploring technological innovations to reduce CO2 emissions. Geologic sequestration (GS), part of carbon capture and storage (CCS) technology, involves the injection of CO2 captured from an emission source into subsurface geologic formations for long-term storage.

To ensure that the large volumes of CO2 injected do not endanger underground sources of drinking water, the U.S. Environmental Protection Agency (EPA) has finalized technical requirements for CO2 injection wells, known as Class VI wells. Operators seeking to inject CO2 for GS must obtain a permit by submitting a comprehensive application that addresses all aspects of the GS project.

Cadmus, as a national expert on GS that has supported EPA throughout the Class VI rule development process, is the only firm that has evaluated these complex permit applications. To date, Cadmus has reviewed seven Class VI permit applications in support of EPA.

Cadmus has developed a holistic permit application review process that considers each element of a multi-faceted permit application and supports the development of protective Class VI permits and associated project plans that govern all aspects of site operation, monitoring, and post-injection site care and site closure.

  • Our geologists, hydrogeologists, and geochemists review extensive information on the site’s geologic features and ground water chemistry and flow to verify that the site is suitable to receive and confine the CO2.
  • Cadmus modeling experts perform multi-phase modeling to evaluate the predicted behavior of the CO2 plume and pressure front within the subsurface. These reviews, which are the heart of the permit application review process, inform determinations regarding site-suitability, monitoring regimes, and the duration of post-injection site care, as well as determining the area where ground water resources may need to be protected.
  • Our well engineers review well schematics to ensure that the well materials are compatible with the CO2 and are of sufficient strength; evaluate mechanical integrity testing and corrosion testing protocols; and ensure that proposed injection operations are appropriate to the well’s design and the local geologic conditions.
  • Cadmus’ risk analysts evaluate emergency scenario probabilities, including the potential for induced seismicity, and verify that a suitable Emergency and Remedial Response Plan is in place.
  • Our finance experts review the applicant’s financial responsibility demonstration to ensure that sufficient funds are set aside to cover the costs of plugging the well, performing all needed post-injection site care, and responding to unforeseen emergencies or remediating contamination.

Information about the Class VI Rule and many EPA products that Cadmus supported as EPA developed the rule and associated guidance documents, is available on EPA’s website.

Learn more about Cadmus’ support for the UIC program.