Corrosion Inhibition of Modified Imidazoline in CO₂ Medium with High Pressure and High Temperature

A new kind of modified imidazoline corrosion inhibitor containing sulfur and phosphor was synthesized using fatty acid and polyamine. The inhibition effect of modified imidazoline HGY-T was investigated using autoclave and electrochemical method in simulated well producing water saturated with 1 MPa CO2 at 80 ℃. The results showed that in the medium with high pressure and high temperature CO2, the corrosion rate of steel was less than 0.076 mm/a with adding 50 mg/L inhibitor. The modified imidazoline is an anodic inhibitor and obeys the Frumkin adsorption isothermal equation.