Research and Application of Weak Alkali Ternary Compound Displacement and Prevention Integrated Agent

Daqing Oilfield weak alkali ternary composite flooding to improve oil recovery but also brought a certain oil well scaling problem, into the peak period of scaling, frequent pickling and scaling measures, coupled with residual acid reflux treatment, the cost increased significantly, And affected by rain and snow weather, some wells due to untimely scaling operations lead to card pump operation, seriously affecting the operation rate of machine mining, according to statistics, the success rate of card solving within 4 h of shutdown is more than 90%, and the success rate of card solving within 4 h is only 50%. For this reason, the development of weak base ternary composite displacement and prevention integrated agent suitable for wellhead dosing process, through low concentration complex free Ca2+ ions, to prevent it from combining with CO32− to produce carbonate scale microcrystals and then produce scaling, in addition, for the carbonate scale microcrystals that have been formed in the production solution, by increasing the concentration of the agent The strong complex group in the component is used to destroy the carbonate microcrystalline skeleton, recapture Ca2+ ions, prevent the growth of microcrystallites, and achieve the effect of molecular state scaling. Field tests show that after the on-site wellhead dosing of the integrated cleaning and prevention agent, the calcium ion content in the production solution has a significant upward trend, from the initial 24.47 ppm to 66.84 ppm, the on-site scaling rate reaches 96.3%, the effective action time of scaling cleaning can reach more than 6h, and it is directly transferred to the production trunk line without backdraining. Which can realize all-weather scale prevention and selective and timely scaling cleaning of machine wells, which greatly improves the efficiency of oil well cleaning and scale prevention, and ensures the stable operation of machine well mining in the chemical flooding stage.