Flow through porous media commonly is modeled using the Darcy equation, where the flux is proportional to permeability, an average property of the media. In reality single phase flow through porous media is sensitive to the geometry and connectivity of individual pores and pore throats. Multiphase flow is even more complex because under some conditions it can develop fingers. Understanding the development of these finger is important for CO2 injection for enhanced recovery of oil and gas recovery and for carbon sequestration, as well as for remediation of aquifer contamination by dense non-aqueous phase liquids. The development of viscous fingers strongly influence the volume of a reservoir or formation that is swept or accessed by a fluid.

 

 

 

Figure 1: We use particle image velocimetry with refractive index matching to measure velocity vector fields for microscale flow through transparent flow cells. PIV works by periodically illuminating tracers in the flow and determining their displacements by cross-correlation. The displacements are then converted into instantaneous velocity vector maps.

 

Figure 2: Here is an example of a velocity vector field for flow through a pore body. We compare the experimentally measured vector field with numerical models of the vector field to test model capabilities.

 

Figure 3: This image shows the development of fingers as air displaces NaI solution in a transparent network flow cell.

 

 

Figure 4: We measure the displacement of the air-NaI interface and how its geometry evolves over time.