Study On Synthesis And Property Of Quaternary Ammonium Type Hydrophobic Association Polyacrylamide

Polymer-surfactant binary combined flooding is now popular in Enhanced Oil Recovery (EOR) to increase the oil recovery. Hydrolyzed polyacrylamide (HPAM) is one of the mostly used polymers and its property such as viscosity is easily changed with the environment. In order to adapt to the reservoir characteristics of high temperature and high salinity, the HPAM used for oil recovery should be modified, that is, hydrophobic monomers should be introduced to the main chain of HPAM and hydrophobic association polyacrylamide (HAPAM) was produced. In order to mix the hydrophilic monomers and hydrophobic monomers in the polymerization reaction, surfactants are usually added in to the solution to make sure the reaction can take place in the micelle. Difficulties such as purification and after treatment of polymer exist in the process and the key to solve the problems is to develop a series of polymeric surfactants, which can be used in HPAM hydrophobization. Water soluble hydrophobic association polymers got from the copolymerization of surfactant as the hydrophobic monomer and acrylamide (AM) exert perfect heat-resistance and salt-resistance as well as certain surface activity. It will surely be widely used in EOR in the future.Based on the above considerations, the purpose of this paper is to synthesize and characterize water soluble hydrophobic associating polymers and study the bulk aggregation as well as practical application. The main work and experimental results are as follows:1. Acrylamide-based, hydrophobically modified copolymers (P(AM/DAGE)) with different content of N-(6-(diallylamino)-6-hydroxyhexyl)-N, N-dimethylhexadecan-1-aminium bromide were synthesized by aqueous copolymerization. The structure, composition and thermal stability of P(AM/DAGE) were confirmed by1H-NMR, FT-IR, elemental analysis and thermal gravimetric analysis (TGA). Aggregation behavior, surface activity and stability of P(AM/DAGE) copolymer in aqueous solution as a function of temperature, salinity and pH were studied by the measurement of surface tension, dynamic laser light scattering and viscosity. It was found that the introduction of hydrophobic groups provides P(AM/DAGE) copolymer a capability of heat-resistance, salt-resistance and excellent acid and alkali resistance. The viscosity of P(AM/DAGE) and SNF synergist system is much higher than SNF only. But the structure of synergized system can easily be destroyed by shearing, resulting in lower viscosity.2. Acrylamide-based, hydrophobically modified polymers (P(AM/VHGE)) containing different content of N-(6-((4-vinylbenzyl)amino)-5-hydroxyhexyl)-N,N-dimethylhexadecan-1-aminium bromide were synthesized by aqueous copolymerization. The structure, composition and thermal stability of P(AM/VHGE) were confirmed by1H-NMR, FT-IR, elemental analysis and thermal gravimetric analysis(TGA). Aggregation behavior, surface activity and stability of P(AM/VHGE) copolymer in aqueous solution as a function of temperature, salinity and pH were studied by the measurement of surface tension, dynamic laser light scattering and viscosity. It was found that the introduction of hydrophobic groups containing aromatic ring can markedly improve P(AM/VHGE) copolymer’s capability of heat-resistance and salt-resistance. Synergism of P(AM/VHGE) with SNF can greatly improve the viscosity of the system.3. A new zwitterionic surfactant with quaternary ammonium salt and sulfonate group (AS-6) was synthesized. The structure of AS-6was confirmed by’H-NMR and FT-IR. Surface activity and aggregation behavior of AS-6as a function of salt and temperature were studied by surface tension and fluorescence measurement. Addition of AS-6resulted in no obvious viscosity reduction for either AP-P4or SNF solution and the viscosity of SNF system wasn’t greatly changed.