%0 Journal Article
%T Axisymmetric Drainage in Hydrophobic Porous Media Micromodels Drainage en g¨¦om¨¦trie axisym¨¦trique dans des milieux poreux hydrophobes ¨¤ deux dimensions
%A Cuenca A.
%A Chabert M.
%A Morvan M.
%A Bodiguel H.
%J Oil & Gas Science and Technology
%D 2013
%I Institut Fran?ais du P¨¦trole
%R 10.2516/ogst/2012050
%X We present studies of axisymmetric drainage in two-dimensional micromodels of porous media using up to date microfabrication and image analysis methods. Drainage of model oil by aqueous solutions is studied at low capillary numbers (Ca) typically encountered during oil recovery operations. We use two types of oil-wet micromodels: one is based on a deposition method for creating a random monolayer of micronic 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. Nous pr¨¦sentons une ¨¦tude de ph¨¦nom¨¨nes de drainage dans des micromod¨¨les bidimensionnels de milieu poreux s¡¯appuyant sur des m¨¦thodes modernes de microfabrication et d¡¯analyse. Le drainage d¡¯huile par des solutions aqueuses est ¨¦tudi¨¦ ¨¤ de faibles nombres capillaires (Ca) commun¨¦ment rencontr¨¦s lors des op¨¦rations d¡¯extraction p¨¦troli¨¨re. Nous utilisons deux types de micromod¨¨les mouillables ¨¤ l¡¯huile : le premier est bas¨¦ sur une m¨¦thode de d¨¦position innovante permettant d¡¯obtenir des monocouches de billes de verre de taille micronique, tandis que le second est microfabriqu¨¦ dans du verre ¨¤ partir de r¨¦seaux poreux al¨¦atoires g¨¦n¨¦r¨¦s informatiquement. Chacun des mod¨¨les utilise un sch¨¦ma d¡¯injection central dans une g¨¦om¨¦trie radiale, ce qui engendre une variation continue du nombre capillaire pendant le drainage. Nous menons tout d¡¯abord une analyse du drainage ¨¤ l¡¯¨¦chelle glob
%U http://dx.doi.org/10.2516/ogst/2012050