Research On AM-EHA Copolymer/SiO₂Composite As Profile Control Agent

Oil is a non-renewable resources and years of continuous mining makes the oilproduction rate decline.At the late period of exploitation in oil field, huge injectionchannel exists in the high permeability oil storage lay; while the effect of most of theprofile control agent for large channel is not satisfactory.The compound current profilecontrol agents only mix flyash, bentonite with the polymer physically, and the structuralstability, the blocking effect is not ideal.So adding inorganic silica particles in thepolymer profile control agent is raised in this paper.The inorganic silica particles weremodified by the silane coupling agent and made the polymer connected to the inorganicsilica particles in the form of chemical bond and the structural stability. The mechanicalstrength and resistance to erosion force was enhanced.The inorganic-organic compoundprofile control agent also has the effect of physical blocking and chemical plugging andalso compensates for the defect of a single profile control agent.In this article rigid silica particles were synthesized by the method of sol-gelmethod and controlled the reaction conditions to uniform particle size, morphologybetter and surface hydroxyl-containing. The particle diameter is about400nm. Silicaparticles were modified by silane coupling agent KH-570at different pH and the betterreaction condition was at pH5acidic to improve the compatibility and chemicalstability of inorganic particles and organic polymers. In this study, composite profilecontrol agent was synthetized by the way of dispersion polymerization to make thesilica surface chemistry grafting with adding monomer acrylamide(AM), ethylhexylacrylate (EHA) and a mix of both monomers.The structure of products was characterized by infrared spectroscopy, scanningelectron microscopy and transmission microscopy. The thermal stability of thecomposite profile control agent was evaluated by using the thermal gravimetricanalysis.The study showed that the silica added with the polymer to make the silicasurface chemistry grafting and inhibit the thermal motion of polymer chain to improveits thermal stability.From the study, the rupture force value was6.59N and the tensilestrength was3.34MPa when silica content was8%and the dispersan was4%. Theapparent viscosity of the composite products of testing showed that the compositeprofile control agent had good temperature resistance and alkali resistance.