Study On Synthesis Of Acrylic Amide Quaternary Copolymer Flooding Agent Containing NDOA Functional Monomer

Water-soluble polymers possess many good properties as viscosity increasing, rheology, dispersibility and so forth, therefore they were widely used in the oil exploitation as tertiary recovery, drilling, completion, wastewater treatment, etc. Among the rest, the water-soluble acrylamide based polymer is the most commonly used chemical agents in tertiary oil recovery technology. Nevertheless, the water-soluble acrylamide based polymers are confronted with a range of issues when the mining technology and drilling depth is promoting. As hydrolyzed polyacrylamide (HPAM), its apparent viscosity would decrease because of molecular chain coil, serious hydrolysis and so forth when reservoir temperature and water salinity rise.This article employed N, N-diallyloctan-1-amine (NDOA), acrylamide (AM), acrylic acid (AA) copolymerized with N-methyl-N-allylmorpholinium bromide (NMQS), N-allyltetradecanamide (NATA), N-allyl-2-phenylacetamide (NAPA), and N-phenylmaleimide (NPMI) in aqueous solution. The four copolymerized water-soluble acrylamide based copolymers are AM/AA/NDOA/NATA, AM/AA/NDOA/NMQS, AM/AA/NDOA/NPMI and AM/AA/NDOA/NAPA. Meanwhile, the optimized copolymerization conditions have been determined. The increasing viscosity, shearing resistance and temperature or salt tolerance of four copolymers solution were investigated. Through comparative analyses with AM/AA/NDOA, better quadripolymer AM/AA/NDOA/NATA was selected. Whereafter, the compounding of optimal copolymer with different type of surfactants and its flushing efficiency were studied. Results are as following:(1) Pyrene was used as the fluorescence probe to investigate the associative behaviors of four copolymers. Among them, the Critical Association Concentration (CAC) of AM/AA/NDOA/NATA copolymer was up to 400 mg/L.(2) AM/AA/NDOA/NATA copolymer solution was the better one, which could be reached the viscosity retention ratio 13.1,30.5,18.4,16.5 and 17.6% when shear rate was 1000 s-1, temperature was 120℃, NaCl, CaCl2 or MgCl2 concentration was 12000 mg/L,1200 mg/L and 1200mg/L, respectively.(3) The combination of AM/AA/NDOA/NATA copolymer and non-ionic surfactant Tween-80 presented better performance. The apparent viscosity of 400 mg/L AM/AA/NDOA/NATA and 120 mg/L Tween-80 combination solution was 145.7 mPa-s, and minimum interfacial tension could be up to 19.10×10-2 mN·m-1.(4) Under conditions of 60℃, simulated oil viscosity 80.13 mPa-s, sand pack F25.8×300 mm, injection rate 0.6 mL/min, injection quantity 0.3 PV, the flushing efficiency of 2000 ppm AM/AA/NDOA/NATA/Tweent-80 could be reached 20.42%.