Study On Synthesis And Properties Of Scale Inhibitor In New Oilfield

Oil field scaling has become a serious problem to the order of oil production and the life of the field. Because the barium sulphate scale has compact structure and is insoluble in the acid, it becomes the most difficult one to remove in all types of scales. In many methods of cleaning the scale, adding the inhibitor into the well fluid circulation system is the most convenient and economical one. Facing the problem of barium sulfate, developing a kind of scale inhibitor to prevent the barium sulfate is an effective way to eliminate this distress.The purpose of this paper is to synthesize two kinds of the barium sulfate copolymer scale inhibitor. Study the effects of feeding mode, monomer ratio, reaction time, initiator dosage, reaction temperature on inhibiting performance, and get the optimum reaction conditions. The investigation of the effect of scale inhibitor was conducted under different temperature, time, pH, cation concentration and salinity conditions. The mechanism of scale inhibition was discussed through the SEM of the barium sulfate scale.This thesis use maleic anhydride, acrylic acid and vinyl acetate as monomers, ammonium persulfate as initiator, synthesize polymer scale inhibitor, named as TR-1.The optimum conditions of TR-1are found as follows:n(MAH):n(AA):n(VAc)=4:2:1, and the amount of initiator added is5%of the total mass of the monomers, and the polymerization reaction time is5hours, and the reaction temperature is80℃. In order to improve product performance, such as temperature and salinity tolerant properties, adding a sulfonic acid monomer AMPS to synthesis inhibitor, named as TR-2.This paper examines in detail the effects of the two scale inhibitor under different concentrations, different temperatures, different holding time, pH environments and salinity. TR-2shows a greater temperature resistance and salt tolerance:at90℃its inhibition rate reaches82.58%, at salinity of30000mg/L, the rate reaches76.40%,which proves TR-2can be used in high temperature and high salinity environments.After the observation of Barium sulfate by the environmental scanning electron microscope, and the study of scale inhibitor’s mechanism, the analysis result shows that TR scale inhibitors have many kinds of mechanism, including chelation solubilization, dispersion, electrostatic repulsion and lattice distortion.