Carboxymethyl Cellulose Type Of Water-based Fracturing Fluid Thickener Applications And Research

Fracturing performance is an important measure that boost production of oil field. Along with a series of high temperature,deep well fracture operation emergence,fracturing fluid of resistance to hot,shear and salt would be needed. Aiming at these requisitions,a series of water-soluble polymer were synthesized. Grafting function monomers of hot-resistence,salt-resistence and shear-resistence onto carboxymethyl cellulose sodium macromolecules, since the solution propertier of polymer improved. Owning to carboxymethyl cellulose sodium was introduced as raw material, the cost of production was reduced.A series of graft copolymerization of carboxymethyl cellulose sodium (CMCNa) with acrylamide (AM) were prepared by grafting acrylamide onto carboxymethyl cellulose sodium in aqueous solution by radical polymerization. Effects of various factors on the intrinsic viscosity were studied,such as the initiator concentration, system concentration,reaction time and CMCNa/AM mass ratio. The results showed that the CMCNa-g-AM of high intrinsic viscosity could be obtained in this reaction system. The optimum condition intrinsic viscosity was 680.2dL/g when the initiator concentration was 0.5wt‰, system concentration was 15 wt%,reaction time was 8h, m (CMCNa):m (AM) =1:4. The chemical structural characteristics were investigated by methods of FTIR,TG and XRD. At the same time, the rheological properties of the polymers aqueous solutions were investigated by rheometer at various temperature and ion strength. The results indicated the occurrence of grafting reaction between AM and CMCNa. And the copolymers of CMCNa-g-AM showed favorable salt-resistance and heat-resistance properties. Moreover, the rheological study on gels which crosslinked by some metal ions, such as Fe3+,Zr4+ and Cr3+ indicated that the obtained graft copolymer showed excellent shear-resistance and could be recommend as thickener for fracturing fluid. The study of gel-breaking showed:gel-breaking time could be controlled by moderating the amount of gel-breaking agent.A series of CMCNa-g-(NVP-co-AM) graft copolymers were synthesized by grafting AM and NVP onto carboxymethyl cellulose sodium in aqueous solution using ammonium persulfate (APS) as initiator. The chemical structural characteristics were investigated by methods of FTIR,TG and XRD. The rheological properties of the polymers aqueous solutions were investigated at various temperature and ion strength. The results showed:When added salt into the polymer aqueous,the viscosity retention rate of polymer aqueous was enhanced and its value was also higher at the temperature of 50℃-65℃compared with CMCNa-g-AM. The measurement of Cr3+ crosslinked gel rheological properties showed that m (NVP):m (AM)=1:4 was the optimum ratio,and the terpolymer of CMCNa-g-(NVP-co-AM) has better properties than the bipolymer of CMCNa-g-AM.Using carboxymethyl cellulose sodium,acrylamide,acrylic acid(AA),2-acrylamido-2-methlpropane sulfonic acid (AMPS) and acryloxyethyl-trimethylamm-onium chloride (DAC) as materials,a series of grafted copolemer was synthesized in acqueous solution initiated by APS. The chemical structural characteristics were investigated by methods of FTIR and TG. The rheological properties of the polymers aqueous solutions were investigated at various temperature and ion strength. The results showed:When added salt into the polymer aqueous,the viscosity retention rate of polymer aqueous was enhanced compared with bipolymer of CMCNa-g-AM aqueous.In the range of 30℃～70℃,it was more hot-resistant than the bipolymer. The measurement of Cr3+ crosslinked gel rheological properties showed that the polymer of CMCNa/AM/AA/AMPS/DAC has better properties than the bipolymer of CMCNa-g-AM.