Synthesis And Performance Evaluation Of Hydrophobic Associating Polymer Gel

Polymeric gels have been widely applied in oil field as water shutoff and profile control agents.However,traditional polyacrylamide（PAM）-based gel,owing to its poor structural stability at high temperature,shows very limited application,especially as a blocking agent for steam channeling in heavy oil reservoir.Thus it is of great significance to develop a high-strength gel with high temperature resistance.In this thesis,hydrophobic monomer M₁（allyl dimethyloctadecylammonium chloride）was prepared by quaternization of N,N-dimethyloctadecylamine and Allyl chloride.Hydrophobic monomer M₂ was prepared by quaternization of N,N-dimethyloctadecylamine with the intermediate which were prepared by chlorination of allyl polyoxyethylene ether with sulfoxide chloride.And the hydrophobic monomer M₃ was prepared through reaction of nonylphenol polyoxyethylene ether with acrylyl chloride.The structures of synthesized compounds were all characterized by NMR and IR.Acrylic amide（AM）and acrylic acid（AA）were used as hydrophilic monomers to copolymerize with hydrophobic monomer M₁ to obtain hydrophobic associating polymer PAMAAM-1.The effects of polymer concentration,hydrophobic monomer concentration,NaCl concentration,crosslinking temperature,and pH value on the gelation performance were studied to optimize the reaction condition and the gelation performance.And the gel microstructure was characterized by scanning electron microscope（SEM）.Under the the following conditions:polymer concentration is 0.5 wt%,the hydrophobic monomer concentration is 1.0%,the organic crosslinking agent concentration is 0.9 wt%,the metal crosslinking agent concentration is 0.1 wt%,and at 80℃,gelant solution started to be cosslinked in 6 hours and became firm within 48 hours with final gel strength grade I（Syddansk code）.This kind of gel shows good high temperature stability at 180℃and can be potentially used in harsh geological environment.The hydrophobic associating polymer PAMAAM-2 was prepared through polymerization of hydrophobic monomer M₂ with other co-monomers.It was purified and characterized by FTIR.Effects of various parameters that affect the gelation time and gel strength including the polymer concentration,hydrophobic monomer concentration,crosslinker concentration and the gelation temperature were evaluated.Gelant formulated with 0.7 wt%PAMAAM-2,2.0%hydrophobic monomer,0.1 wt%metal crosslinking agent and 0.9 wt%organic crosslinking agent and treated at 80℃for 48 h showed sufficient gelation time（5 h）,high rigidity（Sydansk code I）and good thermal stability.Hydrophobic associating polymer PAMAAM-3 was obtained by polymerization of a hydrophobic monomer M₃ with other co-monomers.It was purified and characterized by FTIR.Effects of various parameters that affect the gelation time and gel strength including the polymer concentration,hydrophobic monomer concentration,acrylic content,and pH values were evaluated.Gelant formulated with 0.7 wt%PAMAAM-3,0.5%hydrophobic monomer and treated at 80℃for 72 h showed gelation time（22 h）,high rigidity（Syddansk code I）and good thermal stability.After heated 24 hours at 230℃,it still remains satisfactory gel structure.Lab test results from sand pack experiments showed that the three kinds of polymer gels all exhibited satisfactory plugging effect and good selectivity to the formation.The hydrophobic associating polymers and the gelling systems developed in this work have great industry application potentials.Hydrophobic associating polymer PAMAAM-1 has been successfully applied in Shanjiasi Oilfield as the steam channalling blocking agent.After operation,steam channeling did not occur in the injection period.Compared with the last steam stimulating period,450tons of steam was saved and oil production was increased by about 160 tons for the related wells.The polymer has also been used as an assistant chemical in water flooding with surfactant at Shanlin block in Binnan Oilfield.In the lab test,oil recovery by this binary compound flodding can be a high of 97.4%.Filed test is in progress.