Many excellent articles have reported various aspects of the nature of hydrolyzed polyacrylamide flow in porous media. The polyacrylamide flow in porous media. The degree of mobility reduction is proportional to:
the viscosity of the polymer solution which is greatly affected by the presence of dissolved ions in the water, and
the reduction in reservoir permeability to water caused by flow of the polymer solution.
Penetration of a low mobility polymer slug Penetration of a low mobility polymer slug into a reservoir is limited in part by the adsorption of the polymer onto the rock surfaces or entrapment of the polymer in restricted flow channels. However, the behavior of "partially hydrolyzed" polyacrylamide can depend on both the nature polyacrylamide can depend on both the nature and extent of hydrolysis of the polymer molecule.
Reported in this paper are laboratory investigations of the viscosity and adsorption characteristics of polyacrylamide hydrolyzed to varying degrees with potassium hydroxide. Hydrolysis of polyacrylamide will increase both the measured and relative viscosity in both fresh water and NaCl brines. However, these polymers are sensitive to divalent ions. The higher the percent hydrolysis, the more polyacrylamides are affected by the divalent ions and at the 35% hydrolysis level may begin to precipitate. With fresh injection waters, the higher hydrolyzed polyacrylamides (25–35%) produce the most viscous polyacrylamides (25–35%) produce the most viscous solutions. In high calcium brines, a 15% or lower percent hydrolyzed polyacrylamide can produce greater solution viscosity. produce greater solution viscosity. Sandpack flow tests indicate that the adsorption of polyacrylamide in porous media decreases with increasing hydrolysis. Resistance factor curves display the effects of viscosity and polymer retention on mobility reduction properties. Information outlined in this paper is helpful in showing specific differences in hydrolyzed polyacrylamides that are a function of the degree of hydrolysis and are important in selecting the right polymer for a particular field application. polymer for a particular field application
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