The effect of retarder on gelation time and stability of polyacrylamide chromium(III) gel system.

摘要

Recently the polyacrylamide chromium(III) gel system has been used as a flow control agent to improve the water oil ratio(WOR) in water flooding operations and wells plagued by water conning. Gel divert the movements of water from high permeability thin zones and fractures to the bypassed regions leading to improved sweep effeciency.;Results obtained showed that sodium lactate was effective in prolonging the gelation time from hours to days depending on its concentration. The gel was found to be stable during the period of study. The gel viscosity increased with time and increased if the temperature was increased. The gel viscosity decreased if shear rate was increased. The permeability of the cores was reduced to less than 1.0% of its original value. The results obtained could be used as a guide in the design of water shutoff treatments for field application.;As temperature increases gelation time becomes shorter limiting the application of the gel at high temperature. In this study an evaluation of the effectiveness of sodium lactate in delaying the gelation time at different temperatures was investigated. The gel viscosity at different temperatures, times and shear rates was measured. The plugging effeciency of the gel was studied by injecting the gel solution through sandstone and limestone cores.