Gas-Liquid Flows in Flow Cells and Fracture Models

Gas-liquid multiphase flows in porous media and fractured rock is of importance when carbon-dioxide displaces brine within geological reservoirs during CO₂ sequestration activities. In this paper, experimental and computational modeling of multiphase flows in a porous flow cell and a modeled fracture are described. The experiments performed with the laboratory-scale flow models are described in detail. Experimental data concerning the displacement of two immiscible fluids in the lattice-like flow cell are presented. The flow pattern and the residual saturation of the displaced fluid during the displacement are discussed. It was shown that the gas-liquid flows generate fractal interfaces, with lower fractal dimensions and higher residual saturations at low injection rates. This phenomenon corresponds to viscous and capillary fingering, and is discussed. Numerical simulations of the experimental flow cell are also presented. These are shown to be similar to the experimental results, and then varied to included different surface-fluid interactions not easily studied with the experimental equipment. Numerical simulation results for single and multiphase flows through rock fractures are also presented. A fracture geometry was obtained from a series of CT scans of fractured sandstone and used to construct a laboratory scale model and a computational domain. Computational results showed that the major losses occur in the regions with smallest apertures. These computational results are compared to flows through the experimental model. An empirical expression for the fracture friction factor was also described.