Study of Dual Hydrogel Behavior versus Oil and Water in order to Control Water Production

As polymer gels were successful in water shutoff production, in this research a polymer gel of sulfonated polyacrylamide copolymer and chromium triacetate as crosslinker was studied. For this purpose, bottle tests and filter gel system were used for the first time in the country and also strain sweep tests were carried out. According to the results, quadratic equations based on the parameters were presented predicting the rupture pressure gradient due to the oil and water injection and output gel because of oil and water injection based on polymer and chromium triacetate concentrations. The results showed that polymer concentration among crosslinker concentration and their interaction had the most effect on rupture pressure gradient and output gel due to oil and water injection. Besides, in the constant concentration of crosslinker, the increase of copolymer concentration caused an increase of rupture pressure to 5 times due to the increase of elastic modulus of the gel network and its strength. So by increasing of strain up to 1000%, the gel strength was stable. In fact, up to strain less than 100%, the hydrogel can keep and return to its initial shape. The results of gel rupture led to present a new mechanism to show the disproportionate permeability reduction (called as the creation of greater ruptures inside of gel by oil instead of water) which in that at same condition of experiments the ability of oil in gel rupture and creating greater rupture is more than water.