含CO_2气井腐蚀速率预测方法对比与分析

Methods to Predict Corrosion Rate of CO_2-bearing Gas Wells

针对含CO_2气井普遍存在CO_2电化学腐蚀会严重影响气田安全生产的问题,以鄂尔多斯盆地某区块的天然气井J11P4H及ES4井为样本井,对模型计算、软件模拟、室内挂片、现场挂片等气井腐蚀速率预测方法进行了详细的介绍,并对这4种方法的优缺点进行了对比,通过样本井的现场应用,得知现场挂片法的预测准确性最高,其次为软件模拟法,而室内挂片法准确性最低,并提出以现场挂片测试结果为基准求取软件模拟腐蚀速率的修正系数以及改进室内挂片试验装置和方法等建议。

Very common in most CO_2-bearing gas wells, a problem of CO_2 electrochemical corrosion may seriously affect the safety in field production. In this study, both J11P4H and ES4 wells in one block of Ordos Basin are taken as examples. There are four methods to predict the corrosion rate, including model calculation, software simulation, and in-door and on-site coupon tests. Their own advantages and disadvantages are summed up. Moreover, after their application to these two wells, it is demonstrated that, from the prediction accuracy, on-site coupon method is the best, software simulation the second, and in-door way the last, respectively. In addition,some suggestions are made, including(1) to take the result from indoor way as a reference benchmark to determine a correction coefficient of corrosion rate obtained from software simulation method;and(2) to improve some experimental equipments and procedures of in-door coupon test.