Multi-Polymer Material Cement System Properties Research Increasing Zonal Isolation Performance

The effective zonal isolation of cement sheath during the whole period is the procondition for production in the oil field, Zonal isolation of cement sheath have direct relationship to the production life of the oil well, which have attached most importance to the property of the zonal isolation, and the more research have been done for them. This paper based on the cement slurry's material research, increasing the slurry's properties and the cement stone's solid properties by material designing, improving the long zonal isolation property of cement sheath, and then prolonging the production life of the oil well.This paper optimized the latex polymer SBR, fiber XW, rubber particle XJF-80 and elastic particle EP-II, and optimized stabilization SA, dispersant DS-1, defoamer GR-1 and retarder HN-1 for SBR latex cement system, developed high density, normal density and lightweight SBR latex cement and composite material cement system. latex and composite material cement slurry have good rheologic and low filter property, thickening time can be adjusted and have right-angle property, especially composite material cement stone have good mechanical deformation property.Accomplished latex cement slurry's anti-gas migration research, latex cement stone anti-corrosion research by simulated formation water, and micro mechanism research about latex cement system. SBR latex delayed the phenomenon about the cement slurry's hydrostatic pressure decreasing and increasing the gas invasion resistance for the cement slurry. And latex structure formed inner cement is the primary reason for increasing cement slurry anti-gas migration capacity. Spectral analysis, X-diffraction analysis and SEM analysis showed that latex filled in cement stone and formed netlike structure is the primary reasons to increase cement anti-corrosion.Experiment analysed cement material and additive's effection on cement stone's deformation in uniaxial and triaxial stress. Latex and rubber particle can increase the plasticity deformation capacity of cement stone, and fiber can increase elasticity deformation restorability of cement stone in low stress and plasticity deformation capacity in high stress; When curing time increasing, cement stone's elasticity deformation restorability in low stress and plasticity deformation capacity in high stress decreased. Cement stone is brittleness in uniaixial stress, but brittleness will converted to plasticity when cement stone confined to crack, which showed brittleness-plasticity behavior in triaxial stress.Discussed the theoretical basis for cement stone's mechanical properties improvement from cement hydration and solidification, improve the content of C-S-H gel hydration, adding some additive or material to matrix-plasticity, and adding material to resist internal fissure extension in cement stone can achieve the aim of decreasing brittleness and increasing flexibility of cement stone. This paper put forward the design principle of cement stone's matrix-plasticity to increase zonal isolation of cement sheath, which include four methods such as crystal phase matrix-plasticity, gel phase matrix-plasticity, particle filled in cement hydration and intergranular bridge, which will decrease cement stone's brittleness before...