Comparison between Laboratory Experiments and Detailed Simulations of Unstable Miscible Displacement Influenced by Gravity

This paper presents a study of oil displacement by a less-dense, less-viscous solvent. A comparison is made between laboratory observations and high-resolution simulations in order to test the predictive capability of the numerical model. Observations are made of linear displacement in a Ballotini pack with the principal flow at right angles to the direction of gravity. The pack is sufficiently thin that flow is approximately two-dimensional. Flow is visualized using a dye tracer and recorded on video; subsequent image processing of the video film enables the concentration distribution to be determined for any chosen time. The effluent is analysed by colorimetry. The numerical model used to simulate the experiment has a simplified physical description (two-dimensional displacement of oil and solvent). High-order finite-difference techniques in conjunction with extremely fine grids provide detailed resolution of the flow.