Measurement, Monitoring, and Verification (MMV) Technologies for Sequestration Sites

Securing regulatory approval and building public trust for large-scale carbon sequestration projects requires a robust Measurement, Monitoring, and Verification (MMV) framework. An MMV program is an integrated system of surface and subsurface sensors designed to track the underground movement of injected carbon dioxide (CO2), confirm storage capacity, and provide early warning of any containment failures or migration beyond designated boundaries.

Subsurface tracking is anchored by time-lapse, or 4D seismic surveys. This method involves acquiring conventional 3D seismic profiles across the storage asset before injection begins to establish a geological baseline. As injection proceeds, additional seismic surveys are performed at regular multi-year intervals. Because supercritical CO2 changes the acoustic velocity and density of fluids within the reservoir rock pores, comparing these datasets allows geophysicists to map the expansion of the CO2 plume underground. This ensures the fluid follows predicted simulation models and remains securely within the designated lease area.

To supplement deep seismic mapping, environmental engineers install sensitive pressure and temperature gauges downhole in both the storage reservoir and any overlying monitoring formations. A sudden, unexplained pressure drop inside the storage zone, accompanied by a corresponding pressure increase in a shallower formation above, may indicate a potential seal breach or wellbore cement failure.

In addition, cross-well seismic tomography and electrical resistivity surveys provide continuous, high-resolution fluid saturation profiles between monitoring wells, allowing real-time tracking of plume movement and thickness.

At the surface and near-surface levels, monitoring networks focus on detecting potential leakage anomalies. Eddy covariance towers are deployed across the site to measure real-time atmospheric gas fluxes and detect localized CO2 concentrations above natural background levels. Groundwater wells are also sampled to monitor shallow aquifers for pH changes or increases in dissolved inorganic carbon, which may indicate that CO2 has migrated beyond the caprock and entered shallow water systems.

Through this multi-tiered approach, MMV frameworks help ensure the long-term integrity and safety of carbon storage operations.