NETL researchers Robert Dilmore, Ph.D., and Dustin Crandall, Ph.D., joined carbon capture and sequestration (CCS) experts from government, industry and academia to discuss necessary technical advancements required for safe and permanent storage of carbon dioxide (CO₂) at basin scale during a meeting hosted by the National Academies of Sciences, Engineering, and Medicine.

Dilmore kicked off the second panel of the day with an overarching talk on the technological advancements and challenges for basin-scale CO₂ storage. Serving as the technical director of the NETL-led National Risk Assessment Partnership (NRAP), Dilmore discussed a quantitative risk-based approach to look at large-scale carbon storage deployment. NRAP is a collaboration of five national laboratories focused on quantifying and managing subsurface environmental risks to support implementation of safe and secure large-scale geologic carbon storage.

Speaking about the urgency and scale needed to deploy CCS to meet net-zero decarbonization goals, Dilmore explained that “if we are going to meet these aggressive goals, we need to think beyond the single project and start thinking about how the risks associated with multiple commercial-scale projects operating at a single basin might interact with each other and change the risk profile.”

Because even modeling a single geologic carbon storage (GCS) site is complex, Dilmore explained how NRAP researchers divide the site into components such as cap rocks, possible leakage pathways, faults, fractures and other features. Using ensembles of simulations, the team captures uncertainty and variabilities of these individual components and rapidly builds forecasting models to characterize component behavior. These simulations can then be used to create a whole-system model to explore risk performance.

The interactions between sites at a basin are even more complex. Dilmore explained that when multiple injection sites are located at a basin, researchers must realize that the risk may not simply be the sum of the individual site risks, and there may be interactions between sites that have implications at a basin scale.

“For example, pressure interferences may occur between adjacent commercial-scale CO₂ injections into saline formations at a sedimentary basin,” Dilmore said. “This could increase subsurface risks associated with wellbore leakage, fault leakage and induced seismicity. In addition to those direct risks, pressure buildup could also increase the cost of GCS.”

To understand and manage these potential risks, Dilmore explained that NRAP is working to develop and demonstrate a first-of-its-kind tool to assess subsurface environmental basin-scale risks associated with rapid commercial-scale GCS deployment.

A panel commenced following Dilmore’s presentation that focused on more specific aspects of the necessary technical advancements for basin-scale carbon storage. Crandall joined experts from industry

and government during the panel to discuss how CO₂ moves through geologic formations. Specifically, he talked about CO₂ wettability, which fundamentally refers to how CO₂ interacts with the native fluids and rock under the high temperature and pressure of the subsurface — critical information for knowing where CO₂ will travel.

“Groups are concerned that when the pressures increase in a basin, supercritical CO₂ could pass through the caprock that is supposed to seal in the gas,” Crandall said. “Based on our research, we don’t think this should be an issue when looking at wettability and contact angle.”

Crandall closed out his talk by emphasizing how critical understanding of the microscopic behavior of real rocks at real subsurface conditions is to describing the macroscopic motion of injected CO₂. Crandall leads work supporting this goal at NETL, where he performs lab characterization of rock cores using computer tomography scanners with flow-through capabilities, which allows direct measurement of fluid/rock interactions at representative subsurface pressures and temperatures.

Click here to watch the presentations from Dilmore and Crandall as well as all of the other talks from the day’s meeting.

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By leveraging its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.