Monitoring, Verification, and Accounting (MVA) Project Descriptions Basic Science of Retention Issues, Risk Assessment & Measurement, Monitoring & Verification... Methodology for Conducting Probabilistic Risk Assessment of CO2 Storage in Coal Beds (INEEL) New Development of Novel Monitoring Tools for Geologic Sequestration Project Geological Sequestration - Enhancement of Natural Seals In Field, Continuous, Non-Invasive Soil Carbon Scanning System Geochemical Analyses of Surface and Shallow Gas Flux and Composition over a Proposed... CO2SINK (German) Collaboration Development of Science-Based Permitting Guidance for Geologic Sequestration of CO2 in Deep... IEA GHG Weyburn-Midale CO2 Monitoring and Storage Project Stored CO2 & Methane Leakage Risk Assessment & Monitoring Tool Development: CO2 Capture... Low Cost Open-Path Instrument for Monitoring Atmospheric Carbon Dioxide at Sequestration Sites Geologic Seq. of CO2 in a Depleted Oil Reservoir: A Comprehensive Modeling & Site Monitoring Project Advanced Carbon Measurements for Terrestrial Measurement, Mitigation, and Verification Accounting Protocols Reference Shelf MVA Best Practices Manual

The primary goal of the U.S. Department of Energy’s (DOE) Carbon Sequestration Program’s Monitoring, Verification and Accounting (MVA) Focus Area is to develop and demonstrate a broad portfolio of monitoring tools, applications, and accounting requirements that can meet DOE’s defined goals of demonstrating 95 percent and 99 percent retention of CO₂ through Geologic Sequestration (GS) by 2008 and 2012, respectively. The 95 percent and 99 percent retention levels are defined by the ability of a GS site to detect leakage of CO₂ into the atmosphere at levels of 5 percent and 1 percent of the stored amount of CO₂.

This portfolio is categorized into three types of monitoring technologies:

• Primary Technology- a proven and mature technology or application capable of handling the minimum monitoring requirements that could meet the 95 percent and 99 percent CO₂ containment goals for CCS projects for 2008 and 2012, respectively.
• Secondary Technology- an available technology /protocol that can aid in accounting for injected CO₂ and/or provide insight into CO₂ behavior that will help refine the use of Primary Technologies.
• Potential Additional Technology- a technology /protocol which is research related and might answer fundamental questions concerning the behavior of CO₂ in the subsurface and might have some benefit as a monitoring tool after testing in the field.

These technologies are currently being used in several geologic storage injection projects worldwide. Each geologic storage site varies significantly in risk profile and overall site geology, including target formation depth, formation porosity, permeability, temperature, pressure, and seal formation. MVA packages for commercial-scale projects are tailored to site-specific characteristics and geological features to maximize understanding of CO₂ behavior and determine most effective monitoring tools across different geologic regimes.

The overall goal for monitoring will be to demonstrate to regulatory oversight bodies and the general public that the practice of geologic storage is safe, does not create significant adverse local environmental impacts, and is an effective GHG control technology. In general, the goals of MVA for geologic storage are to:

• Improve understanding of storage processes and confirm their effectiveness.
• Evaluate the interactions of CO₂ with formation solids and fluids.
• Assess environmental, safety, and health (ES&H) impacts in the event of a leak to the atmosphere.
• Evaluate and monitor any required remediation efforts should a leak occur.
• Develop the ability to account for all CO₂ stored in a particular reservoir.
• Provide a technical basis to assist in legal disputes in the unlikely event that any impacts from sequestration occur (groundwater impacts, seismic events, crop losses, etc.).

The example to the right is time lapse seismic image of CO₂ plume migration from the Sleipner project in Norway. The upper images are cross-sections through the injection point and the lower images show impedance changes at the top of the plume. The initial pre-injection survey is on the left and middle and right images monitor migration of the CO₂ plume over the next five and seven years.

The life cycle of a geologic storage project involves four phases. Monitoring activities will vary among these phases:

1. Pre-Operation Phase: Project design is carried out, baseline conditions are established, geology is characterized, and risks are identified.
2. Operation Phase: Period of time during which CO₂ is injected into the storage reservoir.
3. Closure Phase: Period after injection has stopped, during which wells are abandoned and plugged, equipment and facilities are removed, and agreed upon site restoration is accomplished. Only necessary monitoring equipment is retained.
4. Post-Closure Phase: Period during which ongoing monitoring is used to demonstrate that the storage project is performing as expected until it is safe to discontinue further monitoring. Once it is satisfactorily demonstrated that the site is stable, monitoring will no longer be required except in the very unlikely event of leakage, regulatory requirements, or other matters that may require new information about the status of the storage project.

Determining the appropriate monitoring technique in each phase is a key factor for successful geologic storage of CO₂, and can provide information to address safety and environmental concerns, address research questions, and provide verification for national accounting of GHG emissions and support GHG registries. Based on risk assessment, evaluation of the project goals, and mandatory monitoring requirements, a decision tree for selection of monitoring techniques for a particular research or operational geologic storage project can be constructed for each phase. For additional information please see the MVA Best Practices Manual.

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Decision tree for pre-operational and operational phase monitoring techniques for geologic storage.