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Accueil > Publications > 2013

Axisymmetric Drainage in Hydrophobic Porous Media Micromodels

par Bodiguel Hugues - publié le

We present stud-
ies of axisymmetric drainage in two-dimensional micromodels of porous media using up to date
microfabricationand image analysis methods. Drainage of model oil by aqueoussolutions is studied at
low capillary numbers (Ca) typically encountered during oil recovery operations. We use two types of
oil-wetmicromodels : oneis basedonadepositionmethodforcreatingarandommonolayerofmicronic
glass beads, while the other is made using computer generated random networks etched in glass using
wet-lithography. Both models have a central injection scheme and a radial geometry, resulting in a
continuous variation of the capillary number during the course of drainage.
We first carry out an analysis of experiments at global micromodel scale using computer based image
analysis coupled with flow rates and pressure drop measurements. Basic relevant parameters such as
permeability, porosity of the micromodel and residual oil in place after waterflooding are extracted.

We then take advantage of the ease of observation in transparent micromodels to investigate the
drainage phenomenon at local scale. Local saturation and front width are measured as a function
of the local capillary number. Interestingly, because of the radial flow geometry, our experiments
allow a continuous plotting of the micromodels capillary desaturation curve on several decades. As
expected but never precisely observed, all points of various experiments collapse on a single capillary
desaturation curve for a given micromodel. However, we observe dissimilar behaviors between the two
types of micromodels. We discuss this phenomenon in light of the pore scale geometrical differences
between the two models.