NETL: Carbon Storage - Monitoring, Verification, and Accounting (MVA)

The image below displays the various monitoring approaches that could be employed to monitor the fate of the CO₂ within a geologic system (subsurface, near-surface, and atmospheric). Data analyzed through acquisition of information from these tools could also be used to optimize injection operations, sweep efficiency, and identify potential release pathways.

	Application
	Atmospheric testing is used to identify possible releases of gaseous CO₂ into the atmosphere from storage projects. It is unlikely that CO₂ will reach the atmosphere once injected into suitable storage formations. In the event it does, technologies will be necessary to monitor and quantify releases of CO₂ from wellbores, faults, and diffuse soil releases.
	Research Focus
	Research the development and application of novel chemical and isotopic tracers which may be precursors to a CO₂ release at the ground surface. Develop systems to monitor CO₂ flux from soils to determine changes from baselines to identify and quantify releases. Research potential open pathways for CO₂ migration and develop CO₂ detectors to identify releases from injected CO₂.
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	Application
	Detecting near-surface releases in the vadose zone and in groundwater sources are important to protecting underground sources of drinking water (USDW). It is also important to be able to detect pooling of high concentrations of CO₂ in low lying areas and in structures. The benefits of monitoring in this zone are that natural variations of CO₂ in the soil are typically minimal since biological activity typically occurs closer to the surface.
	Research Focus
	Utilize remote sensing platforms to detect gas concentrations, land surface deformations, and biological impacts as indicators of a CO₂ release and the fate of CO₂ in the subsurface. Advance water quality and soil gas analysis for isotopes, tracers, and organic and inorganic carbon as advanced warning signs of release. Advance geophysical methods needed to image CO₂ or sense changes in geochemistry in the vadose zone.
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	Application
	In order to achieve 99 percent storage permanence, monitoring tools must be able to locate CO₂ in the target and surrounding storage formations and ensure that it is remaining in place. Carbon dioxide will migrate in the target formation through paths of least resistance. It is important to understand the fate of the injected CO₂ to help identify possible releases as well as inform future monitoring events and simulation models. Carbon dioxide measurement is relatively easy near the injection well, but it becomes more challenging and expensive to perform these measurements over a large area typical of a geologic storage project. Technologies developed should be able to sense small changes from background levels and identify changes in CO₂ levels outside the intended target storage formation.
	Research Focus
	Advance geophysical methods and protocols to image CO₂ or sense changes in geochemistry in the target or surrounding formations. Develop remote sensing techniques that monitor parameters, such as land surface deformation, to correlate CO₂ movement in the deep subsurface. Improve sensors for subsurface monitoring of pressure and temperature that are able to withstand prolonged logging time in extreme pressure and temperature areas. Improve tools and interpretation of data from well logging and seismic surveys that may increase the resolution of existing technologies and assess integrity of wellbores. Develop novel tracers and sampling tools and methodologies for deep geologic sampling to use as indicators of CO₂ transport in the target formations.
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	Application
	A number of monitoring tools may be deployed during various phases of the storage project. Project developers will need to design systems and protocols for deploying different technologies to address events that arise during a storage project. Certain technologies are low cost, but can serve as indicators of release, while others may only be deployed after an event has been identified. Research is needed to develop systems that would inform project developers of the capabilities of different MVA technologies and when they should be applied.
	Research Focus
	Research and quantify the capabilities of different technologies to monitor and measure CO₂ in the subsurface. Research and design monitoring networks to detect, confirm, and quantify a CO₂ release to support mitigation efforts and GHG reporting requirements.
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These research areas, in conjunction with small- and large-scale injection projects, are expected to produce MVA tools that can be applied in a systematic approach to address target formation(s) depth(s), porosities, permeabilities, temperature(s), pressure(s), and associated caprock formation properties for each project. An additional benefit of research efforts will be the reduction in cost of these tools. Finally, the increased capabilities of MVA tools will yield the ability to account for the location of injected CO₂ and any potential release. This not only meets the project storage goals, but also ensures the protection of human health and the environment.

The following table summarizes NETL's active projects that are currently addressing the critical monitoring, verification, and accounting barriers.