油套管钢在氯化钙溶液中腐蚀及缓蚀性能研究

Corrosion and Inhibition Performance Study of Oil Casing Steel in Calcium Chloride Solution

为了获得普通碳钢在常规压井液中腐蚀性,并找到一种腐蚀控制途径,利用失重法和电化学方法研究了N80、P110钢在1.35g/cm^3 CaCl_2溶液中不同温度、高温高压,缓蚀剂种类、用量等条件下的腐蚀及缓蚀行为。实验结果表明,随温度的升高N80和P110钢腐蚀加剧,在常压60~80℃,普通碳钢自腐蚀电流密度从10^(-6)A/cm^2增加到10^(-5)/cm^2;4 MPa条件下,温度从90℃升高至150℃时,腐蚀速率增大了1个数量级;80℃下,WLD31A用量仅为30 mg/L时,对N80缓蚀效率可达95.51%,P110钢缓蚀效率可达93.11%;在60~80℃,升高温度有利于提高WLD31A缓蚀效果,N80钢缓蚀效率从88.08%增加到96.51%,P110钢缓蚀效率从61.38%增加到93.11%。

In order to know the corrosion resistance of ordinary carbon steel in the regular killing fluid and find a way tocontrol its corrosion condition, weight loss method and electrochemical methods were used to study N80 and P110 steel′scorrosion situation and corrosion inhibition ability in 1.35 g/cm3 CaCl2 solution at standard pressure and different temperatures,high temperature and pressure, and different types of corrosion inhibitor, dosage. The experimental results showed that withincreasing temperature the corrosion of N80 and P110 steel is intensified. And at the standard pressure with the temperaturerange of 60～80 ?C, the corrosion current density of the ordinary carbon steel raised from 10?6 A/cm2 to 10?5 A/cm2. At 4 MPawith temperature rising from 90 ?C to 150 ?C, the corrosion rate increased an order of magnitude. At 80 ?C with the amount ofWLD31A 30 mg/L, it improved inhibition efficiency on N80 up to 95.51%, and that on P110 up to 93.11%. Within the range of60～80 ?C, elevated temperatures help to improve WLD31A inhibition effect, the inhibition efficiency of N80 increases from88.08% to 95.51% and P110 from 61.38% to 93.11%.