Risk Assessment

Risk analysis is a critical tool used iteratively in conjunction with site characterization, monitoring, and public outreach throughout all of the stages of a geologic CO2 storage project to help meet the goals of safe, secure, and verifiable permanent storage.

  Examples of relationships among Features, Events, Processes, and Potential Impacts. Available in Best Practices for: Risk Assessment and Simulation for Geologic Storage of CO2, 2013 Revised Edition, NETL.
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Risk is defined as the product of the probability of an event or outcome and the likely cost or consequence of it. As applied to geologic storage, the primary focus is on the risk of adverse impacts from a potential loss of CO2 storage integrity resulting in unplanned CO2 migration out of the confining zone. A more comprehensive risk analysis also assesses the potential for adverse impacts from other project-related operational and financial events, such as events that occur on the surface or in the policy arena. Some of the potential consequences associated with loss of CO2 storage integrity involve public safety and health, environmental (ecosystem) damage, greenhouse gas (GHG) emissions to the atmosphere, injury to natural resources (e.g., water and fossil fuels), and financial loss for investors or insurers.

Risk assessment is used in many disciplines; and, in recent years, tools and methods have been adapted for application to CO2 geologic storage projects. Extensive databases of features, events, and processes have been developed to facilitate identification and analysis of site- and project-specific risks. Various tools have been developed to both qualitatively and quantitatively evaluate the risk (likelihood and consequences) of various scenarios related to carbon capture and storage projects.

Research Agenda and Challenges

Improvements are needed in quantitative risk assessment strategies that are critical to the design, optimization, and implementation of an effective risk assessment plan related to CO2 injection operations. In addition to identifying potential risk factors, it is necessary to determine specific consequences of events. Numerical simulation, based on field operating experience, is used to support the development of a rigorous risk assessment strategy that includes quantification of risk factors.

Research pathways for risk assessment include:

  • By 2020: Develop qualitative risk assessment tools for formations targeted in first mover projects. Research includes efforts to develop standard processes for risk assessment and efforts to integrate risk assessment with reservoir simulation, operations design, and CO2 monitoring activities.
  • By 2030: Develop improved quantitative risk assessment tools and integrate risk assessment with field operations. Research includes post-audits of past projects for validating specific risk assessment approaches and comparing predictions with observations to demonstrate reliability of methods and models.
GSRA Risk Assessment Research Timeline
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NETL-Supported Risk Assessment Research

NETL supports projects that are addressing research challenges within the Risk Assessment key technology area. Example’s of NETL-supported research in this area include: (1) developing screening tools for improved understanding of reservoir geomechanical processes and conditions related faults, fractures, and caprock flaws; (2) experimentation to study pore level and petrophysical property changes in different rock types exposed to CO2 and brine; (3) developing novel statistical-neural genetic algorithm methods to study the leakage risks for wells exposed to CO2; and (4) supporting the National Risk Assessment Partnership (NRAP), a multi-DOE lab initiative that is helping to quantify uncertainties and risks necessary to remove barriers to full-scale CO2 storage deployment.

Noticeable porosity changes of dolomite cores with exposure to different concentrations (increasing to the right) of CO2 and brine. Drastic increase in porosity could potentially present leakage pathways (University of Utah project DE-FE009773).
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  NRAP’s integrated assessment model simulates carbon storage system behavior and calculates probability of leak events.
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The GSRA webpage offers links to detailed information on projects performing research in this area.