INTERNSHIP PROPOSAL Enhanced oil recovery - Laboratoire de
the pore walls, modification of the adsorbed conformation because of the flow ... chromatography effect, apparent slip at the wall of the polymer solution, chain ...
INTERNSHIP PROPOSAL Laboratory name: Laboratoire de physique des solides CNRS identification code: UMR 8502 Internship director’surname: Frédéric RESTAGNO e‐mail:frederic.restagno@u‐psud.fr Phone number:+33(0)671818693 Web page: http://www.lps.u‐psud.fr Internship location: Orsay (or Chicago at Northwestern university) Thesis possibility after internship: YES (ANR fundings already obtained)
Enhanced oil recovery : from control of the interfaces to nanofluidic flows Multiphase flow of simple fluids in porous media is already a challenging problem, in particular when we consider all the length scales involved in oil‐recovery which can span over 9 orders of magnitude, from sub‐micron to km scales. The addition of polymers, i.e. deformable objects of size comparable to the pores, in one of the phases, does not make life any simpler! A large number of phenomena involving solution‐surfaces interaction can take place during the transport of the polymer solution inside the porous medium: adsorption of the polymer on the pore walls, modification of the adsorbed conformation because of the flow field, size exclusion chromatography effect, apparent slip at the wall of the polymer solution, chain degradation if the elongational component of the flow is too high… All these phenomena are not well described and there is a clear need for a neat step forward in physical understanding in order to better simulate polymer flow in porous media and its impact on oil recovery. This will be achieved by working in a consortium involving an industrial partner (TOTAL) and 3 academic groups (Orsay, Grenoble and Lyon). Different questions are arising: 1 – What are the mechanisms of formation of an adsorbed layer on a surface under flow? 2 – What are the molecular mechanisms of interaction between a surface anchored polymer layer and a flowing polymer solution? Different mechanisms of surface layer‐polymer solution interactions will be explored comparing neutral and electrostatically charged polymers. i) The effect of a polymer flow on an existing adsorbed surface layer: will the flow produce desorption of already adsorbed polymer chains? ii) If the flowing polymer solution does not desorb the surface chains, it can modify their conformation. This has been indirectly shown in the case of polymer melts through an onset of strong slip at the wall and recently directly observed in the case of polymer melts using neutron reflectivity experiments. Is the mechanism of disentanglement between surface anchored chains and bulk chains relevant for polymer solutions? For which concentrations, which kinds of polymer – polymer interactions? What are the incidences on friction? iii) This will be our last question: what are the consequences of this change of polymer conformation induced by the flow on the overall dissipation? 3 – Finally, what happens in the case of confined solutions? This questions are the program of a whole PhD thesis involving the use of different experimental techniques going from Total Internal Reflection Fluorescence, Microfluidics, Quartz crystal microbalance and nanorheology experiments in close collaboration with a group in Grenoble. More precisely, during his internship, the student will be responsible of measuring the effect of a flow on the adsorption on a solid surface, and to understand how the molecular parameters influence the adsorption and the chain conformation. Condensed Matter Physics: YES Macroscopic Physics and complexity: