Preparation Of Hydrogels And Its Application

Hydrogels which can be used as blocking agent and diverting agent for acidizing were prepared, and the behavior of the mixture from cationic and PAM viscosity was investigated.(1) By the polymerization of AM, copolymerization of AM and AMPS, copolymerization of AM and DMDAAC, the polyacrylamide hydrogels, AM-AMPS hydrogels and AM-DMDAAC hydrogels were synthesized respectively. Such factors as initiator, mass percent of monomer, crosslinker and so on were researched, and the optimum conditions to synthesize three kinds of hydrogels were obtained. Based on the performance evaluation, it is showed that AM-AMPS hydrogels was the best and the AM-DMDAAC hydrogels had good capability of calcium salt tolerance.(2) Considering crosslinkers with ester groups could hydrolyze and break off, a special diverting agent which could first swell and then dissolve in acid solutions, was designed by the polymerization of AM, AMPS and PEGDA. The optimum conditions to synthesize this diverting agent were as follows: the molar ratio of AM to AMPS was 1:1, the mass percent of monomer was 25%, the mass percent of initiator was 0.1%, the mass percent of cross linking agent in monomer was 0.1%. The obtained hydrogels could swell by 18 times in 15% hydrochloric acid solution when the temperature was 90℃, and after 12 hours it could dissolve. Because of this behavior, it is possible for the hydrogel to block up the layer temporarily.(3) The combination system was prepared by mixing cationic hydrogels and HPAM. The viscosity enhancement, temperature resistance, salt tolerance and shearing resistance of combination systems were evaluated. The result indicated that the introduction of the cationic hydrogels could enhance the viscosity of HPAM solution. When the cation degree of hydrogel was 5%, and the concentration of two solutions were correspondent, and the volume ratio was 1:1, the effect of viscosity enhancement was the best. When the rate of shearing was 170s^-1, the viscosity could be increased from 31.1mPa.s to 40.5mPa.s.