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Mechanism of microgel formation in partially hydrolyzed polyacrylamide

Journal Article · · J. Pet. Technol.; (United States)
DOI:https://doi.org/10.2118/2498-PA· OSTI ID:5611299

The reduction of water mobility by solutions of partially hydrolyzed polyacrylamides is brought about not only by an increase in viscosity but also by a decrease in effective permeability to water. This decrease in water permeability is due to retention of the polymer within the pore channels so that there is a marked reduction of flow. In addition to this resistance effect, it was found that the polymer retained within the pore channels causes pseudo dilatant flow at high rates of shear. This increase in viscosity with increasing rate of flow may be important in displacement of oil, particularly in systems with a markedly heterogeneous permeability. Until recently, it was not understood how the polymer retained within the pore structure could restrict flow, since even though these polymer molecules have molecular weights of the order of several million, there is still a pronounced disparity between molecular size and the diameters of the main flow channels in a typical porous medium. Methods are described for controlling the microgel size and new experimental evidence is presented that seems to indicate that the mechanism of polymer crosslinking is largely due to anhydride linkages formed by elimination of water from COOH groups present along the polymer chain.

Research Organization:
Pennsylvania State Univ
OSTI ID:
5611299
Journal Information:
J. Pet. Technol.; (United States), Journal Name: J. Pet. Technol.; (United States) Vol. 21; ISSN JPTJA
Country of Publication:
United States
Language:
English