偏磨腐蚀油管寿命预测模型研究

Research on Life Prediction Model for Eccentric Wear Corrosion Tubing

抽油机井中油管的偏磨与腐蚀是影响其使用寿命的重要因素,而目前没有一种有效的方法能够预测偏磨腐蚀油管的使用寿命。鉴于此,同时考虑油管偏磨与腐蚀2个因素,使用MG-200型摩擦磨损试验机与高温高压反应釜分别开展了油管的磨损试验与腐蚀试验,分析了不同的试验条件对磨损速率与腐蚀速率的影响,此外还利用有限元法对偏磨腐蚀油管进行了强度分析,研究了磨损深度与腐蚀深度对油管强度的影响。基于偏磨试验结果、磨损能量理论与偏磨杆管几何关系,建立了偏磨速率计算模型,根据腐蚀试验结果,使用最小二乘法拟合出腐蚀速率计算函数,结合试验与强度分析建立了偏磨腐蚀油管寿命预测模型。预测模型在5口现场实例井的油管寿命计算中,最大计算误差为13.5%。研究结果可为抽油机井检泵周期的设定提供参考。

Partial wear and corrosion of tubing in rod pumped wells are important factors that affect their service life. At present, there is no effective method to predict the service life of tubing with partial wear and corrosion. At the same time, considering the two factors of tubing eccentric wear and corrosion, the wear test and corrosion test of tubing were carried out using the MG-200 friction and wear tester and the high temperature and high pressure reactor respectively, and the influence of different test conditions on the wear rate and corrosion rate was analyzed. In addition, the finite element method was used to analyze the strength of eccentric wear corrosion tubing, and the influence of wear depth and corrosion depth on tubing strength was studied. Based on the eccentric wear test results, the wear energy theory and the geometric relationship between the eccentric wear rod and tube, the eccentric wear rate calculation model is established. According to the corrosion test result, the corrosion rate calculation function is worked out by means of the least squares fit, and life prediction model for worn-corrosion tubing is built by combining the test and strength analysis. The life calculation of 5 field example wells shows that the maximum calculation error is 13.5%. The research results can provide a reference for guiding the pump inspection cycle.