Corrosion Evaluation And Corrosion Inhibitor Selection Of CO₂ Flooding Produced Water In Huaziping Oil Field

As one of the main oil recovery method of tertiary oil recovery in Huaziping oil field,CO₂ flooding technology has a good development prospect.However,CO₂ flooding will cause serious CO₂ corrosion on the wellbore of the producing well and surface pipeline,resulting in reduced service life of pipeline and equipment and enormous economic losses.Corrosion inhibitor is the most frequently used technology to inhibition CO₂ corrosion in oil field development,which has the characteristics of simple process,high efficiency and low cost.This thesis in view of the produced water with CO₂ flooding corrosion problem in Huaziping oil field,the corrosion rule of produced water was studied,the CO₂ corrosion inhibitors were designed and synthesized,and its corrosion inhibition was evaluated and the best formula was screened,which provided a reference for the corrosion protection in CO₂flooding.The corrosion behavior and characteristic of J55 tubing steel in produced water under simulated CO₂ flooding conditions were studied by high temperature and high pressure weight loss experiment,canning electron microscope and energy spectrum analysis.The corrosiveness of CO₂ flooding produced water in Huaziping oil field was mainly caused by CO₂ corrosion and Cl^-induced pitting,and the corrosion rate was faster.With the increase of temperature,the corrosion rate increased first and then decreased.The corrosion rate reached the maximum at 110?,and the corrosion rate was 2.23 mm/a.With the increase of CO₂ partial pressure,the corrosion rate increased,and the thickness and degree of irregularity of the corrosion product film increased.Oleic acid imidazoline,oleic acid imidazoline quaternary ammonium salt and quinoline quaternary ammonium salt were synthesized as inhibitors of CO₂ corrosion inhibitors.The results of FTIR showed that the target product was synthesized.Six kinds of compound inhibitors for inhibiting CO₂ corrosion were designed.The results of water solubility and emulsification showed that these inhibitors had good water solubility and no obvious emulsifying tendency,which can meet the requirements of field use.The electrochemical performance of the corrosion inhibitors were studied by potentiodynamic polarization and EIS test.The results showed that corrosion inhibitors B,C and F had good effect on Anti-CO₂ corrosion.Inhibitors B and C were anodic corrosion inhibitors,and the inhibition mechanism was"negative catalysis".The corrosion inhibitor F was a mixed-type corrosion inhibitor,and the inhibition mechanism was"geometric coverage effect".The effect of corrosion inhibition in produced water under simulated CO₂ flooding conditions was by high temperature and high pressure weight loss experiment,canning electron microscope and energy spectrum analysis.The results showed that the optimum concentration of inhibition was 100 mg/L.Under this concentration,the corrosion rate of J55tubing steel was less than 0.076mm/a,and the corrosion of J55 tubing steel was slight.The corrosion inhibitor C had the best effect,and the corrosion inhibition rate was 85.63%when the concentration was 100mg/L.