| Chromium acetate-polyacrylamide systems are used primarily to treat fracture systems, casing leaks, and near wellbore regions in matrix rock where short gel times are acceptable. The relatively rapid chromium acetate-polyacrylamide reaction limits the application of this technology to near-wellbore treatment of matrix rocks. Pre-gel aggregates form during the gelation reaction and some of these aggregates are filtered from the solution, thus building up high flow resistance and limiting the depth of penetration into the porous matrix. This thesis describes research to delay the in situ gelation of a polyacrylamide--chromium acetate system for in-depth penetration into the porous medium. Data are presented to show the effect of added acetate on gelation times of bulk gelant in bottle tests. In situ gelation characteristics of the gelant with added acetate during transport in a porous medium was demonstrated from a series of displacements in six-inch-long sandpacks. (Abstract shortened by UMI.)... |
