NETL: Carbon Storage - Simulation and Risk Assessment Focus Area

Specifically, simulation models also can be used to: (1) predict the thermal impacts and hydrologic flow of CO₂ in the target formation; geochemical and thermal changes that may occur in the storage formation; (2) geomechanical effects on the target formation, seals, and release pathways, such as faults, fractures, and wellbores; and (3) the effect of biological responses in the presence of supercritical CO₂.

A risk assessment is often performed at the early stages of a project to help in site selection, communicating project goals and procedures to the public, and aiding regulators in permitting for the project. Risk assessment is also necessary in identifying potential issues with a storage site and developing mitigation procedures so that immediate action can be implemented should an issue arise. Risk assessment and management for CO₂ storage efforts generally include two primary aspects: (1) programmatic risks (including resource and management risks) that may inhibit project progress or costs, and (2) storage (technical) risks inherent to the scientific and engineering objectives of a storage project. Calculation of risk profiles is a common approach to assessing the predicted performance of large-scale projects. These also help determine long-term project costs and potential liabilities in support of decisions on decommissioning and long-term stewardship.

	Application
	A number of two- and three-dimensional numerical codes for simulating coupled groundwater and heat flow that are capable of modeling CO₂ flow though porous and fractured media are currently being developed. These models are critical to predicting the performance and informing the project developer of risk and operational design of CCS projects.
	Research Focus
	Improve limited research focus of existing models to improve coupling of thermal and hydrologic processes. Improve regional hydrologic modeling of flow for basin-scale CCS operations that account for variances in depositional environments.
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	Application
	Chemical modeling for CCS can take several forms and ideally should include processes such as aqueous speciation, dissolution/precipitation, redox processes, ion-exchange between solutions and minerals, and surface chemical reactions occurring at phase interfaces.
	Research Focus
	Improve reaction kinetics. Examine effects on porosity and permeability. Examine effects on geomechanical processes. Research coupling with transport and multiphase flow and reaction.
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	Application
	Geomechanical processes include the effects of fluid pressure, elastic and non-recoverable deformation, fracturing and larger-scale faulting in a geologic setting. Simulation algorithms have shown extremely rapid advances over the past two decades, including sophisticated gridding techniques and mathematical optimization methods.
	Research Focus
	Improve coupling of hydrologic and mechanical models for impacts on faults, fractures, and wellbores. Examine the impact of regional pressure increases on basin-scale seismicity. Examine the scaling of pore-scale models to predict project and regional impacts of mechanical processes that might impact hydrologic flow and risks.
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	Application
	The influence that microorganisms have in the subsurface underscores the importance of understanding how CO₂ storage will affect microbial activity. This information may be used to prevent or mitigate negative consequences associated with CO₂ injection. Furthermore, understanding CO₂ reservoir microbiology may offer opportunities to enhance CO₂ retention.
	Research Focus
	Assess the impacts to microbial communities. Examine the effects on permeability to reduce risks of release.
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	Application
	Risk assessment is the systematic identification of features, events, or processes (FEPs) which might pose a potential risk to the operations or impacts from a CCS project. Understanding these risks is critical to the design, optimization, permitting, and implementation of CCS projects. In addition to identification of potential migration pathways, the identification of specific consequences relating to a release of CO₂ is equally important.. For geologic storage, some potential consequences that have been identified in laboratory studies include brine contamination of USDWs, unintended migration of CO₂ into petroleum resources or other infringement on mineral rights, and long-term CO₂ seepage into the atmosphere. Building upon field operation experience and simulation modeling will support the development of rigorous risk assessment modeling for CCS.
	Research Focus
	Develop standard processes for risk assessment. Develop risk assessment databases for FEPs to predict risk and impacts in different types of geologic formations. Compare the predictive methods against observations to demonstrate reliability and accuracy as well as to reduce uncertainties. Integrate risk assessment with simulation, operation design, and monitoring activities to optimize performance.
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Information on active simulation and risk assessment projects receiving DOE funds that aim to obtain the Carbon Storage Program's goals are provided in the following table.