The flow behavior of polymer solutions in filtered deionized water throughcapillary tubes and porous media at room temperature and at several highertemperatures was determined experimentally and is describes analytically.
A unique technique of preparing a cartridge-type core holder arrangement wasdeveloped. The porous medium was enclosed in a high temperature resistant epoxyresin in such a manner that the Flow through the core was linear. Rheologicalcharacterization of the polymer solutions and their flow through the porousmedia were carried out in a completely metal-free system. This restriction wasimposed because of the sensitivity of the polymer solutions to any metalliccontamination. The "power law mode" with its constitutive equations and theresistance factor concept Formed the basis for the quantitative description ofthe experimental results.
The polymers used in this investigation were partially hydrolyzedpolyacrylamides, polysaccharides, and poly-ethylene oxides. The effect ofpolymer concentration on both rheological behavior and flow through porousmedium of the solutions at several temperatures from about 75 ºF to about 180ºF were also investigated.
Results are presented as plots of resistance factor vs. superficial velocityand as flow behavior indexes vs. temperature at the temperatures mentionedabove.
Oil recovery from most reservoirs after primary depletion and waterflooding islow and many times less than 50% of the oil originally in situ. Forheavy oil reservoirs the Figure may be even lower. Nowadays, with the shortageof crude oil and gas supplies, the improvement of oil recovery efficiency hasbecome one of the most important problems of petroleum engineering.
It has been known for many years that the efficiency of a waterflood processcan be improved by decreasing the water oil mobility ratio of the fluids in thesystem. Such a change leads to a better sweep efficiency and to a moreefficient displacement of the oil from the swept zone. It is possible toachieve this goal by either increasing the water viscosity or decreasing thepermeability to the flow of water. Many investigators1,2,3,4 haveshown that the use of certain high molecular weight synthetic polymers in verydilute solutions decreases water mobility in porous media 5 to 20 times morethan would be expected from the solution viscosity alone. This fact indicatesclearly that the reduction of adverse mobility ratios is economically feasiblein many situations.
Since the middle 60's, partially hydrolyzed acrylic polymers have been used asa means of reducing the water – mobility in secondary recovery operations. Mobility control by the use of dilute solutions of partially hydrolyzedpolyacrylamides appears to be due not only to an increase in viscosity broughtabout by the dissolution of the polymer but also to the effective permeabilityof the displacing phase being reduced because polymer molecules are adsorbed orotherwise retained in the porous structure. However, the true mechanism of thereduction in mobility by polymer solutions is not completely understood.