Residual Trapping In Subsurface CO2 Systems

What Is Residual Trapping?

Residual trapping is a mechanism where injected CO2 becomes immobilized in the smallest pores of a rock formation as buoyant fluid threads break into isolated droplets. Capillary forces hold these droplets in place, preventing large-scale migration even when pressure gradients shift.
It plays a major stabilizing role in geologic carbon handling systems, where the immobilized portion of CO2 supports long-term containment by limiting plume extension and reducing the effective mobile volume.
Because the trapped phase cannot reconnect into a continuous flow path, its behavior reshapes how reservoirs evolve after injection stops.

Example:

Residual trapping limits how far a CO2 plume can travel once immobile droplets occupy pore spaces.

Related Concepts:

• Capillary Trapping
• Solubility Trapping
• Plume Migration