Study On The Synthesis And Performance Of The Temperature And Salt Resistance Polymer Fluid Loss Control Agent

With the development of petroleum driliing industries,the traditional fluid loss additives has been unable to meet the demands of drilling technology owing to a sharp rise in the depth of drilling and the gradual increase in temperature and salinity.Consequently it is necessary to develop the copolymer fluid loss additive for high temperature resistant and salt tolerant.According to the design principles of molecular structure,the fluid loss additive for high temperature resistant and salt tolerant copolymer is synthesized by free radical aqueous polymerization,based on acrylamide(AM),allyl polyethylene glycol(APEG),acrylic acid(AA)and ethylene benzene sulfonate(SSS).The fluid loss performance of the products is evaluated by the single factors experiments of the synthesis conditions,which demonstrates that the optimal mass ratio of AM,APEG,AA and SSS is 8:4:1:1,the pH value being 8,the dosage of monomers taking up 40wt%by the total mass,the mass ratio of APS and SHS being 3:1,the dosage of initiators making up 0.3wt%by the total mass of monomers,the temperature of reaction being 60?,and the reaction time being 4 hours.The structure of copolymer is characterized by the fourier transform infrared spectrometer(FT-IR)spectra,nuclear magnetic resonance hydrogen spectrum(1H-NMR),thermogravimetric and simultaneous differential thermal and gel chromatography.The experimental results shows the structure is the same as the designed structure by FT-IR and 1H-NMR;the polymer has good thermal stability and the temperature of decomposition reaches 230?;the range of molecular weight distribution is narrow by gel chromatography analysis,which demonstrates the polymerization condition is reasonable and reduce the occurrence of the side reaction.The dosage of fluid loss additive in drilling fluid and the abilities to resist the high temperature and tolerate NaCl,KCl,MgCl2,CaCl2 and the multiple salts is assessed,showing the optimal dosage of fluid loss additive is 1.0wt%;when the fresh water cement slurries have been aged for 16 hours at the temperature of 240?,the coploymer still has good abilities of fluid loss,which demonstrates the fluid loss additive has well performance of resisting the high temperature performance;the fluid loss additive has fine competence of fluid loss in the drilling fluid of containing the 36wt%NaCl,34wt%KCl,0.7wt%MgCl2,0.5wt%CaCl2 and the multiple salts respectively,indicating the fluid loss additive has excellent performance of tolerating salt and the performance of tolerating NaCl,KCl,MgCl2 and CaCl2 is stronger guadually.The mechanism of polymer fluid loss additive is analyzed by the scanning electron microscopy(SEM),Melvin laser granulometer(PSA)and Zeta potentiometer to observe the microstructure of filter cake and measure the size distribution of the clay particles and Zeta potential of the drilling.The experimental results shows that the polymer fluid loss additive have the good adsorbed and dispersion abilities worked on the clay particles and the rational size distribution of the clay particles,which can form the tight filter cakes and have good fluid loss performance.