Abstract

Two-phase gravity currents in carbon dioxide sequestration

The effect of capillary forces on the propagation of two-phase gravity currents is investigated analytically and numerically, motivated by situations arising in the geological storage of carbon dioxide (CO2), as well as other areas such as groundwater hydrology. In such settings, a fluid invades a porous medium saturated with an immiscible second fluid of different density and viscosity. The action of capillary forces in the porous medium results in spatial variations of the saturation of the two fluids within the current. The local saturation is determined by the vertical balance between capillary and gravitational forces, known as gravity-capillary equilibrium. Gradients in the hydrostatic pressure along the current drive fluid flow in proportion to the saturation-dependent relative permeabilities. The effect of this on the propagation of axisymmetric, two-phase gravity currents is discussed and comparison drawn with data from the CO2 sequestration site at Sleipner.

Madeleine Golding, DAMPT , University of Cambridge

Miscible viscous fingering induced by a simple chemical reaction

Viscous fingering
VF is a hydrodynamical instability that occurs in porous media when a less viscous fluid displaces a more viscous one. We investigate here numerically how such an instability can be triggered by a simple A+B→C reaction when a solution of one reactant is displacing linearly a miscible solution of another reactant of same viscosity producing a more viscous product C at the interface.

Thomas Gérard, BP Institute, University of Cambridge