Dispersion of imbibition fronts
Institut Français du Pétrole - 92852 Rueil-Malmaison
2 Laboratorio de Física Estadística de Sistemas Desordenados, Centro de Física, IVIC Apartado 21827, Caracas 1020-A, Venezuela
3 Center for Bioinformatics, Saarland University - P.O. Box 151150 66041 Saarbrücken, Germany
Accepted: 7 March 2003
We have studied the dispersive behaviour of imbibition fronts in a porous medium by X-ray tomography. Injection velocities were varied and the porous medium was initially prewetted or not. At low velocity in the prewetted medium, the imbibition profiles are found to be distinctly hyperdispersive. The profiles are anomalously extended when compared to tracer fronts exhibiting conventional (Gaussian) dispersion. We observe a strong velocity dependence of the exponent characterizing the divergence of the dispersion coefficient for low wetting-fluid saturation. Hyperdispersion is absent at high imbibition velocities or when the medium is not prewetted.
PACS: 47.55.Mh – Flows through porous media / 68.35.Fx – Diffusion; interface formation / 68.08.Bc – Wetting
© EDP Sciences, 2003