Features - January 2016

Advancing Carbon Storage through Collaboration

When carbon storage research teams from five U.S. Department of Energy National Laboratories joined forces in 2010 to address the critical questions related to geologic storage of anthropogenic CO2, it was the beginning of a powerful initiative known as the National Risk Assessment Partnership (NRAP)—a team that has boldly demonstrated the problem-solving value of collaboration in tackling tough energy-related technical challenges.

NRAP leverages DOE’s capabilities across multiple disciplines—including reservoir engineering, geology, geophysics, statistics, and environmental engineering—to help remove barriers to wide-spread deployment of carbon dioxide (CO2) storage. It’s critical work with potentially world-changing benefits because carbon capture and storage (CCS) is one of the key technologies identified in global efforts to combat climate change. Specifically, the partnership is developing a defensible, science-based methodology for quantifying the evolution of environmental risk, through time, for the most likely types of CO2 storage targets (such as, saline aquifers, depleted oil and gas formations). This methodology will be used to guide site selection, operational decision making, and risk management, which will also ensure safe and effective CO2 storage. As part of that effort, NRAP is developing monitoring and mitigation protocols to reduce uncertainty in sites’ predicted long-term behavior.

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NRAP is working to understand the performance of carbon storage sites (depicted here) and reduce the uncertainty in the sites’ predicted long-term behavior.

One of the main challenges associated with carbon storage is gaining an understanding of the key attributes of a particular carbon storage site, and how it will respond to large-scale CO2 injection and storage. The problem is that the characteristics and geology of the subsurface systems that will be used to store CO2 are in many ways different from engineered systems, such as power plants or carbon capture facilities, which can be studied and manipulated, tested and refined. Geologic systems are formed over millions of years by natural processes and so they are inherently variable and uncertain. Because they are underground, it is not possible to control most of their characteristics, as is done in fully engineered surface processes. Our understanding of these systems depends largely on limited information from often sparse well observations, from newly collected (and expensive to acquire) geophysical data, and from past site (oil and gas) production history. NRAP is working to understand the performance of these sites in the context of that uncertainty, and to understand the associated implications for long-term liability, toward removing a key barrier to the business case for CO2 storage.

Collaboration underpins the success of the NRAP researchers. NRAP members include the National Energy Technology Laboratory (NETL), Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and the Pacific Northwest National Laboratory.  Led by NETL, the NRAP multi-lab team meets regularly to advance the scientific understanding of carbon storage and how to reduce the risks associated with it. To best understand where to focus their efforts to address key challenges in this field, NRAP researchers rely on input from a broad stakeholder group, which includes entities from government regulators, international oil companies, service companies, academic institutions, and other NETL collaborators such as the Regional Carbon Sequestration Partnerships.  These stakeholders provide key data and insights from field experience that NRAP researchers rely on to focus development of NRAP risk assessment methodologies and predictive tools. Working with these external stakeholders on an ongoing basis ensures that NRAP’s work remains relevant to the carbon storage community.

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NRAP researchers collaborate at NETL.

To date, the collaboration has resulted in a number of technical reports contributing to the state-of-knowledge regarding long term performance of carbon storage systems and system components (reservoir performance, well and seal leakage, groundwater impacts, and induced seismicity behavior), and establishing methodologies to quantitatively assess risks through time.  

Recently, NRAP researchers have used this expanded knowledge base to build tangible applications as well. Enter the NRAP Toolset. Now in beta-testing, the NRAP Toolset comprises seven new computational modeling tools designed to help predict long-term risks of large-scale carbon storage operations:

  • NRAP Integrated Assessment Model—Carbon Storage (NRAP-IAM-CS) simulates long-term behavior of the full carbon storage system (from reservoir to receptor), generates risk profiles, quantitatively estimates storage permanence, and identifies key drivers of risk.
  • Reservoir Evaluation and Visualization (REV) Tool generates CO2 plume size and pressure differential (an important indicator for potential unwanted fluid migration from the storage reservoir) over time and visualizes probable reservoir behavior.
  • Wellbore Leakage Analysis Tool (WLAT) evaluates existing wells for leakage potential and explores leakage response based on the characteristics of the well.
  • Natural Seal ROM (NSealR) evaluates the impact of potential breaches in seals on migration of fluids (CO2 or brine) outside of the primary target zone.
  • Aquifer Impact Model (AIM) rapidly estimates volumes of an aquifer impacted if a CO2 or brine leak occurs. 
  • Design for Risk Evaluation and Monitoring (DREAM) is a prototype model that evaluates and selects optimal monitoring designs for long-term CO2 storage.
  • Short Term Seismic Forecasting (STSF) forecasts the likelihood that seismic events will occur and how often, over the short term, in response to active CO2 injection.  

Additional tools are in the works, including a technology for forecasting the long-term risk of induced seismicity—minor tremors that could be caused by large-scale injection. Many of these tools will advance into a second phase of NRAP research and development to incorporate new functionality and feedback from testers and stakeholders.

The NRAP collaboration is also being considered in the context of international CO2 storage efforts. NRAP researchers participate in collaborations like the International Energy Agency Greenhouse Gas Research and Development Programme, which provides important networking opportunities and information exchange, keeping NRAP members abreast of important developments around the world. The NRAP toolset’s beta testers include international organizations, such as Taiwan-based Industrial Technology Research Institute (ITRI). Closer to home, and at their request, NRAP has been communicating with North America-based organizations, comprised of representatives from industry and academia with experience and expertise in subsurface engineering. Such collaborations could also help expand the toolset by providing important data sets.  NRAP’s participation in strategic international collaborations is expected to expand going forward.

Ultimately, the NRAP Toolset and the improved scientific base developed by the collaborative will help operators design effective and efficient monitoring and mitigation strategies. They will help regulators and their agents quantify risks and perform cost-benefit analyses for specific CCS projects. And, they will help enable financiers to invest in CCS projects with greater confidence because costs of long-term liability can be estimated more easily and with less uncertainty. By facilitating deployment of carbon storage to aid global efforts against climate change, NRAP is a model of success enabled through collaboration.  

For more information on NRAP and the Toolset, please visit EDX.