Capillary equilibrium of bubbles in porous media

Abstract

Significance We show how pore geometry modulates the capillary equilibrium states of a trapped bubble inside a porous medium using a simple conceptual model. The model explains recently published data on bubbles trapped in porous rock samples. We explain the counterintuitive observation that bubbles with large surface areas in the subsurface can remain thermodynamically stable for geologically long times. The stability is the result of a modified relationship between a bubble’s surface free energy and volume due to geometric confinement. The implications are relevant to applications ranging from petroleum recovery, to CO 2 sequestration, to groundwater oxygen supply, and to fuel-cell water management.

Topics & Concepts