The Synthesis Of Novel Hydrophobically Associating Polymer And Interaction With Surfactants

In recent years, with the exploitation of oil well coming into the anaphase stage,fracturing has shown its importance as one of technical measures of oil increasing production.In the course of fracturing treatment, Fracturing fluid performance has become the key factor of construction measure. At present, water-based polymer fracturing fluid is the most commonly used fracturing fluid, but it is easy to bring damage to reservoir. A newly developed viscoelastic surfactant fracturing fluid almost no damage to reservoir, but the construction cost limits its application. For this reason, develop a kind of fracturing fluid with high quality, low cost and low damage has become our primary goal.In this paper, we synthesized a polymerizable surfactant monomer methacryloxyethyl dimethyloctadecylammonium bromide. Thereafter, the monomer reacted with acrylamide and acrylic acid through aqueous solution polymerization, as expected, hydrophobically associating polyacrylamide was synthesized. It was fully analyzed and discussed how the performance of polymer solution was affected by the experimental factors, and the optimum synthesis conditions were determined. The copolymer and hydrophobic monomer were characterized by the nuclear magnetic resonance spectroscopy and infrared absorption spectrum, and the molecular structure was confirmed. In addition, it was investigated how the performance of the polymer solution were affected by the polymer concentration, the hydrophobic monomer concentration, temperature and salinity. The results showed that a critical associating concentration would appear with the increase of polymer concentration.Above the critical concentration, because of the intermolecular hydrophobic association, they showed remarkable tolerance of high temperature and high salinity. We also found that with the increasing of hydrophobically associating polyacrylamides concentration, the surface tension of solution is decrease. The fluorescence spectrum results showed that the critical association concentration is about 0.15%.We investigated the interaction of hydrophobically associating polyacrylamide and surfactant with viscometry, surface tension, fluorescence spectrum and scanning electron microscopy. The result showed that the interaction between hydrophobically associating polyacrylamide and anionic sodium dodecyl sulfate is driven by electrostatic force andhydrophobic interaction, so the hydrophobe induce a specific aggregation of surfactant micelles around the hydrophobe cluster to form mixed micelles at concentration lower than the cmc of surfactant, and the interaction is three period model. However, the interaction between hydrophobically associating polyacrylamide and NVES is only driven by hydrophobic interaction, so the interaction between them is occurred at concentration much higher than the CMC of surfactant, and the viscosity of mixed system increased monotonically. The interaction between hydrophobically associating polyacrylamide and zwitter-ion betaine surfactant is around CMC. When the surfactant hydrophobic chain length is relatively short, at low concentration of surfactant, the viscosity of mixed system remain unchanged,continue to increase the concentration of surfactant,the viscosity decreases. On the contrary,the surfactant hydrophobic chain length longer than 12,the viscosity increased monotonously.