What is the NRAP Initiative?

The National Risk Assessment Partnership (NRAP) has joined international efforts to develop the risk assessment tools needed for safe, permanent geologic CO2 storage. NRAP members include five national DOE laboratories that have been conducting collaborative research for the Office of Fossil Energy’s Carbon Sequestration Program for many years: NETL, Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and the Pacific Northwest National Laboratory.

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NRAP is using Science-based Prediction to Quantify Potential Risks

NRAP receives input from industry, government, non-government organizations, and academia regarding research needs for large-scale CO2 storage deployment. The NRAP collaboration also keeps abreast of international developments by participating in collaborations like the International Energy Agency Greenhouse Gas Research and Development Programme’s Risk Assessment Network.

The primary objective of NRAP is to develop a defensible, science-based methodology and platform for quantifying risk profiles at most types of CO2 storage sites to guide decision making and risk management. NRAP will also develop monitoring and mitigation protocols to reduce uncertainty in the predicted long-term behavior of a site.

To assist in effective site characterization, selection, operation, and management, NRAP is considering potential risks associated with key operational concerns, as well as those associated with long-term liabilities. Operational issues include the management of reservoir pressure and stress to avoid conditions that might induce seismic activity. Issues associated with long-term liabilities include groundwater protection and storage permanence to avoid CO2 leakage.

Proposed Research, Expected Benefits

The primary objective of National Risk Assessment Partnership (NRAP) is to develop a defensible, generalized, and science-based methodology and platform for quantifying risk profiles at CO2 storage sites, and to then apply and extend those tools and applications to understand how assessed risks can be managed, if needed, through mitigation and other engineering interventions, and how uncertainties in assessed risks can be reduced through strategic monitoring, conformance evaluation, and iterative improvement of site characterization and system-wide performance prediction. The methodology must incorporate and define the scientific basis for assessing residual risks associated with long-term stewardship of CO2 storage sites, and help guide site operational and regulatory decision-making and risk management. Development of an integrated, strategic, risk-based monitoring and mitigation protocol is part of the NRAP objective; this protocol and related monitoring design tools will help to reduce uncertainty in the predicted long-term behavior of the site and thereby increase confidence in storage integrity.

In Phase II of the NRAP project, researchers will apply NRAP risk assessment methodologies and predictive tools to field demonstration sites to test and validate their utility in a real-world setting and identify areas of focus for further methodology and tool development – particularly with respect to risk management and uncertainty reduction. To that end, key Phase II efforts will include the following thrusts:

Containment Assurance

Containment assurance is an iterative process of risk assessment, risk mitigation, monitoring, conformance evaluation, and model updating. This task will develop methodologies to support key aspects of this process, and will contribute to a demonstration of the implementation of the entire process at a real or synthetic CO2 storage site. Methodology development will focus on two areas. The first, building on Phase I activities, is to develop methods to assess and manage risks associated with leakage of CO2 from the storage reservoir. The second is to contribute to the development of a science-based process for integrating the monitoring data with the leakage risk assessment and management strategy. Where appropriate, the methodologies developed in this task will be incorporated into the NRAP Integrated Assessment Model-Carbon Storage (NRAP-IAM-CS) software package.

Induced Seismicity Risk

Induced seismicity risk is a concern for many CO2 storage projects, as demonstrated by seismic activity observed at several recent CO2 injection operations. In NRAP Phase II, researchers will develop seismic risk assessment and risk management strategies to help operators inject CO2 in a safe and efficient manner. This will expand on induced seismicity work from NRAP Phase I and add new capabilities. Through engagement with program-funded CO2 storage projects and other stakeholders, NRAP will identify opportunities to apply these tools to real field data and determine useful technology-transfer activities. Future activities will focus on performing end-to-end risk assessments using relevant field data, and integration of insights from that work into an NRAP Seismicity Management Protocol.

Strategic Monitoring for Uncertainty Reduction

NRAP Phase II will include significant efforts to assess the effectiveness of monitoring methods to detect leakage, develop optimized monitoring designs, and develop monitoring design and analysis approaches that can be incorporated into the IAM for reduction of uncertainty in risk performance through time. This will include the development of methods to model monitoring with focus on indirect (remote sensing) geophysical monitoring. Monitoring performance will be modeled based on many (hundreds to thousands) realizations of numerical simulation of subsurface performance, as a function of varying and uncertain operational and geologic properties, to quantitatively assess the effectiveness of detection for various monitoring technologies. Effort will be made to reduce the computational burden and improve computational time by developing reduced-order models for monitoring, and by application of statistical approaches to efficiently select modeled scenarios. Results from these efforts will serve as the basis for design of optimal monitoring networks (e.g., minimum time to leakage detection, maximum probability of leak detection), and will be incorporated into integrated assessment modeling for risk management and uncertainty reduction.

Validation of Risk Assessment Tools and Methodologies Using Synthetic and Field Data

In Phase II, NRAP researchers will place significant emphasis on the demonstration, application, and validation of various NRAP tools and methodologies. In the near term these efforts will focus on application of the NRAP Phase I risk assessment tools using technically relevant field data both for individual component models, as well as the NRAP-IAM-CS. In future years, new and revised Phase II NRAP tools and methodologies will also be applied to test their utility to address issues related to risk management (e.g., system-wide mitigation performance evaluation) and uncertainty reduction (e.g., strategic monitoring for conformance assessment and iterative refinement of site characterization and related predictions). In addition to testing tools with field data, tool testing will occur with a synthetic data set based on hypothetical CO2 storage system response at the Kimberlina site, California. The Kimberlina site synthetic data will serve as a common testbed for use by NRAP researchers, and the broader geologic carbon storage community.

Addressing Critical Questions Related to Assessment and Management of Environmental Risk at CO2 Storage Sites

Finally, in Phase II, NRAP researchers hope to identify and distill critical insights from all NRAP assessment methodologies and tool development and demonstration efforts to inform stakeholders and their decision making on critical issues of geological carbon storage risk assessment, risk management, and uncertainty reduction. To accomplish this, researchers will employ tools and methodologies developed previously under NRAP Phase I, as well as new methodologies, tools, and scientific findings developed in NRAP Phase II, to perform analyses targeted to addressing those questions. A key aspect of this work will use the NRAP approach of considering probabilistic, whole-system performance to develop those insights in the context of system uncertainty.