An experimental study of filtration mechanisms of pre-gel aggregates during flow of a polyacrylamide-chromium(III) gel system in porous media

This experimental work was conducted to investigate the relative significance of filtration mechanisms during flow of a reacting polyacrylamide-chromium(III) gel solution through uncosolidated sandpacks. Use of native silica sand (hydrophilic) and silanized silica sand (hydrophobic) to examine the effectiveness of adsorptive retention, and aging the gel system before injection into sandpacks to investigate the role of growth of pre-gel aggregates on development of flow resistance were the two attempts to accomplish the objectives of this study.; The results of displacement runs showed that silanization of silica sand increased adsorption of polymer on silica sand and thereby accelerated the buildup of flow resistance. The results also indicated that aging the gel solutions before injection into sandpacks caused earlier development of flow resistance. Polymer analysis showed lower polymer retention in runs with aged gel injection compared to runs with non-aged gel injection. Lower polymer retention and earlier resistance development in runs with aged gel injection was attributed to the significant role of straining mechanism in these runs. Based on the results of this study it was postulated that aging the gel solution enhanced the reaction between polymer molecules and chromium(III) ions and presumably reduced the adsorption sites on polymer molecules so that they could not adsorb on porous media. (Abstract shortened by UMI.)...