Study On Copolymers As Fluid Loss Additive For Oil Well Cement Slurry

Four type copolymers were synthesized include Poly(AM/AMPS), Poly(AM/AA),Poly(AM/AMPS/AA), Poly(AM/AMPS/AA/NVP) through polymerization of the main Acrylamide(AM) monomer and the other monomers:2-Acrylamido-2-Methyl-Propanesulfonic Acid(AMPS), Arcrylic Acid(AA) ,N-Vinyl-2-Prrdidone(NVP).A series of copolymers were synthesized through changing ratio of monomers. The structure and the character of the copolymers was analysized. The property of the copolymers in oil well cement was tested as fluid loss additive. According to viscosity analysis of copolymers and property of copolymer cement, ascertain the appropriate monomers'ratio. The fourier transform infra-red (FTIR) spectra of copolymers indicated that aimed product was synthesized with high productivity. Thermogravimetry analysis (TGA) of copolymers revealed that the Poly(AM/AMPS) had the most high thermostability. Its beginning decompose temperature is 255℃and peak decompose temperature is 302℃. Based synthesis and compare of copolymers, more study synthesis and applied properties of pulverous Poly (AM/AMPS), discovered the synthesis technics of pulverous Poly (AM/AMPS) and synthesized pulverous copolymer which the average molecular weight is 1,851,300. The test of this copolymer grout indicate that the product can be used under 150℃, it can be used in water for NaCl concentration 9% by the weight of the water and can be used after at least 21 days without influence properties. The pulverous Poly (AM/AMPS) in oil well cement had severity prolong grout concretion time at 95℃, 0.1 MPa, which an be used at 150℃,70MPa through adding pyroretard of oil well cement. The pulverous Poly (AM/AMPS) had no negative influence on grout fluidity and dissociate water. This product can be better used through adding cational styrene-butadiene latex or hydroxyethyl cellulose (HEC), and 24 hours intensity of the cement were all strengthened.