02933nab a2200265 4500 20260520004413.0 260224s2012 xxu ing Inglés Shear Stability of EOR Polymers jun. 2012 12/12/2012 ; 12/12/2012 4 p. ; 335-339 Transcripción del resumen del autor An experimental study of shear stability of several high-molecular-weight polymers used as mobility-control agents in EOR projects has been performed in well-controlled conditions. The shearing device was made of a capillary tube with an internal diameter (ID) of 125 µm, through which polymer solution was injected at a controlled rate. The setup enables a precise measurement of the shear rate to which the polymer macromolecule is submitted. The degradation rate was measured by the viscosity loss induced by the passage into the capillary tube. The shear rate was gradually increased up to 106 sec–1 while checking degradation rate at each stage. Different commercial EOR polymer products were submitted to the test with polyacrylamide backbone and different substitution monomer groups. All macromolecules behave as flexible coils in solution. The parameters investigated were Molecular weight (between 6 and 20x106) Nature of substitution group (acrylate, ATBS/sulfonate, nVP/vinyl-pyrrolidone) Salinity Polymer shear degradation increases with molecular weight and salinity, but decreases with the presence of acrylate, ATBS, and nVP. All results can be interpreted in terms of chain flexibility. The highly flexible polyacrylamide homopolymer is the most sensitive to shear degradation. Introduction of acrylate groups in the polymer chain induces some stability because of the rigidity provided by charge repulsion, which vanishes in the presence of high salinity because of the screening of acrylate negative charges. ATBS and VP groups, which are larger in size, provide significant chain rigidity, and thus better shear stability. It is also shown that some very-high-molecular-weight polymers, after passing the shearing device, attain a final viscosity lower than lower-molecular-weight products with the same chemical composition. This factor has to be taken into account in the final choice of a polymer for a given field application. As a comparison, although less popular today than 2 decades ago, xanthan gum (XG), which behaves like a semirigid rod, is shown to be much less sensitive to the shear-degradation test than the coiled polyacrylamides (Sorbie 1991). 2 SPE Journal 17 ARTICULO Zaitoun, A. 9558 Makakou, P. 52864 Blin, N. 52865 Al-Maamari, R.S. 52866 Al-Hasmi, A.R. 52867 Abdel-Goad, M. 52868 Al-Sharji, H.H. 12579 187495 187495 0 0 0 0 255314 BAAB BAAB 2026-03-06 200059614 0 200059614 2026-03-06 00:17:23 2026-03-06 ARTICULO