Permeability Reduction Mechanisms Involved in In-Situ Gelation of a Polyacrylamide/Chromium(VI)/Thiourea System

Summary An investigation of the in-situ gelation of a polyacrylamide/chromium(VI)/thiourea system under flow conditions in unconsolidated sandpacks is presented. High flow resistance was observed in a localized section of the sandpacks that was consistent with deep-bed filtration mechanisms. A method to measure the size of aggregates in a gel solution is also presented. Results from this method showed that the gel aggregates grow with reaction time and distance traveled through the sandpack, supporting the conclusion that filtration is a dominant factor in the in-situ gelation process under flow conditions.