Research On The Synthesis And Performance Of A New Scale Inhibitor For ASP Flooding Wells

With the application of ASP flooding technology,a large amount of scale will be produced in the formation near the production well,wellbore and surface pipeline equipment.However,the accumulated scale will damage the oil extraction equipment and even cause the rupture of the sucker rod in serious cases,which will scrap the oil well and bring serious economic losses to the production.Therefore,it is very important to explore new scale inhibitors for ASP flooding oil wells.The formulation of the new ASP flooding oil well scale inhibitor use maleic anhydride and acrylic acid as main monomers,sodium hypophosphite and acrylamide as reaction monomers and hydrogen peroxide as initiator.After polymerization,a deep yellow viscous transparent liquid is obtained,and the corresponding stretching vibration peak is observed from the infrared spectrum of the polymer.By examining the molar ratio of reactants and the effects of reaction temperature,time and other conditions on viscosity,the best synthesis conditions were obtained.The reaction temperature was 120℃,n（MA）:n（AA）:n（SHP）:n（AM）:n（H₂O₂）=1.8:1:0.41:0.76:2.64,and the reaction time was 1 hour.By investigating the effect of scale inhibitor on the scale inhibition performance and microstructure of calcium carbonate and calcium sulfate,the following conclusions are obtained:（1）the developed compound flooding oil well scale inhibitor can destroy the crystal growth of CaCO₃and CaSO₄,and make the original crystal shape disordered,the scale is loose and easy to remove;（2）The new scale inhibitor can produce better scale inhibition effect on CaCO₃at a lower dosage,and the scale inhibition performance on CaSO₄is greatly affected by calcium ion concentration,besides it can maintain better scale inhibition effect under the conditions of high temperature,high pH and long constant temperature time;⑶the analysis of scale inhibition effect of field water samples from Daqing oil field No.2 oil production plant shows that the scale inhibition effect increases when the amount of high scale inhibitor is used,and comparing with the commercial scale inhibitor with oilfield scale inhibitor,the scale inhibition rate is higher at high dosage.