摘要
在套管服役的过程中,酸性气体硫化氢、二氧化碳会对套管产生严重的腐蚀作用,导致套管的强度和寿命降低,甚至造成严重后果。同时,在钻井过程中,套管不可避免地受到钻柱的磨损作用,这不仅导致套管强度降低,而且对酸性气体的腐蚀产生一定的加速作用,导致套管提前失效。论文首先通过磨损套管段应力分布的解析模型确定套管磨损部位的应力集中系数,然后讨论在富含硫化氢环境下套管应力集中对其磨损部位腐蚀速率的影响作用,得到了套管磨损导致其腐蚀速率加速的计算方法。通过实例分析发现,套管磨损产生的应力集中确实在一定程度上加速套管腐蚀,因而在酸性气井钻井过程中更有必要采取有效措施来预防套管磨损。
With the high sour gas, casing strings will be severely corroded by H2S and CO2, which can reduce the casing strength and shorten the casing lifespan. In the meantime, the casing string will be worn inevitably in the drilling process which will not only lower the casing strength and accelerate the corrosion rate, but also even lead to casing failure in advance. The author first gives the method to compute wear depth of the casing and derives the stress concentration index of a wear casing; then uses the electrochemistry knowledge to derive the formula of the impact of stress concentration to corrosion rate. At the end, we take an example to analyze the formula and find that stress concentration has a great effect on the corrosion rate, so it is quite necessary for us to take some effective measures to prevent casing wear.
出处
《石油化工应用》
CAS
2012年第4期5-8,25,共5页
Petrochemical Industry Application
关键词
酸性井
套管磨损
应力集中
腐蚀速率
sour wells
casing wear
stress concentration
corrosion rate
