Synthesis And Properties Of AM/SSS/DMAAC-18 Fracturing Fluid Thickener

Fracturing techniques is an important measure to increase production for reservoir.However,along with the exploitation of oil and gas resources,the formation condition of fracturing operation is more and more stringent.Therefor the researchers have to study synthetic fracturing fluid with the better performance,such as to meet demand to increase production in the high temperature and low permeability formation.For now the research of artificial fracturing fluid thickener,it is difficult to meet the requirements of high temperature resistance and clean at the same time.So It is necessary to developAccording to the characteristics of hydrophobic association,a ternary polymer of acrylamide(AM),n-octadecyl allyldialkyl ammonium chloride(DMAAC-18)and Sodium p-styrenesulfonate(SSS)were designed and synthesized in this work.Through the single factor experiments we found that the optimum synthesis conditions were:the concentration of DMAAC-18 was 1.5mol.%,the concentration of SSS was 0.6mol.%,the reaction temperature was 45 ?,the quality of monomer initiator(azobisisobtltryamide chloride)was 0.2wt.%,reaction time was 6h,monomer concentration was 25wt.%,the reaction pH was 9.The molecular structure of the ternary polymer was characterized by Fourier transform infrared(FT-IR)and nuclear magnetic resonance hydrogen spectrum(1H-NMR)spectroscopy.The results indicate that the obtained product is basically consistent to the designed composition,which means that the AHAPAM is successfully synthesized.The intrinsic viscosity of AHAPAM was 858.5mL/g by Ubbelohde viscometer.Through the study of the influence of the concentration to the polymer solution viscosity by macroscopic viscosity measurement and fluorescent probes from mechanism analysis,the critical associating concentration of polymer AHAPAM(CAC)was determined to be 0.17wt.%.The associating microstructure in solution of AHAPAM before and after CAC were observed by environmental scanning electron microscopy(ESEM),which proved the AHAPAM associating thickening mechanism.Throughrheological experiment,AHAPAM aqueous solution was found to be elastic fluid.And the apparent viscosity of the 0.5 wt%copolymer solution was maintained at 92 mPa s at 140 C and 170s-1 shearing for 1 h,which indicated that AHAPAM have good temperature resistance.AHAPAM fracturing fluid was determined by the national industry standard for the basis of the formula:the concentration of AHAPAM was 0.5wt.%,the concentration of antiswelling agent KCl was 2.0wt.%,the concentration of the clean up additive FC-117 was 0.045wt.%,and the concentration of the gel breaker(NH4)2S2O8 was 0.1 wt.%.And evaluating AHAPAM fracturing fluid performance according to the standard,the experimental results showed that AHAPAM fracturing fluid was a kind of high temperature resistant and clean fracturing fluid.