二氧化碳驱油工艺中油酸咪唑啉对碳钢的缓蚀行为研究

目的 研究CO2驱油工艺中咪唑啉缓蚀剂对油套管P110钢腐蚀的缓蚀机制与规律。方法 模拟长庆油田CO2驱工艺环境为实验条件，采用失重挂片、电化学测试、微观表征等手段，研究油酸咪唑啉缓蚀剂对P110碳钢的腐蚀抑制行为。结果 P110钢的腐蚀速度随着CO2分压的升高而增大，但是增大幅度不明显。当CO2分压为2、6 MPa时，油酸咪唑啉对P110钢腐蚀具有显著的抑制效果，缓蚀效率均超过98%，试片表面基本完整；当CO2分压升高到8 MPa时，油酸咪唑啉的缓蚀性能明显下降，缓蚀效率仅为64.33%，试片表面存在明显的腐蚀特征。结论 CO2分压升高到8 MPa时，P110钢表面携带过剩的正电荷，不利于油酸咪唑啉缓蚀剂的吸附。

Corrosion Inhibition Behavior of Oleic Acid Imidazoline on Carbon Steel in CO2 Enhanced Oil Recovery Process

The work aims to study the corrosion inhibition mechanism and law of imidazoline inhibitor on oil casing steel in CO2 enhanced oil recovery process. The environment for CO2 enhanced oil recovery process in Changqing Oil Field was simulated as the experimental condition. The corrosion inhibition behavior of oleic acid imidazoline on P110 carbon steel was studied via weight-loss measurements, electrochemical tests and surface characterizations. The corrosion rate of P110 steel increased with the increase of CO2 partial pressure, but the increase range was not obvious. When the partial pressure of CO2 was 2 and 6 MPa, oleic acid imidazoline had a significant inhibition effect on the corrosion of P110 steel, the corrosion inhibition efficiency was more than 98%, and the surface of the specimen was basically complete. When the CO2 partial pressure increased to 8 MPa, the corrosion inhibition performance of oleic acid imidazoline decreased obviously, and the corrosion inhibition efficiency was only 64.33%. There were obvious corrosion traces on the surface of the specimen. When the CO2 partial pressure increases to 8 MPa, the P110 steel surface carries excess positive charge, which is not conducive to the adsorption of oleic acid imidazoline inhibitor.