Casing wear is a serious problem in highly-deviated wells because serious wear will lead to casing deformation, drilling tool sticking and failure of subsequent operations. The purpose of this paper is to predict casing wear depth and evaluate its effect on casing strength degradation in highly-deviated well drilling operation. Special attention has been given to the algorithm to achieve the prediction and evaluation. The effect of tool joint on contact force distribution is considered in contact force model. Then a wear depth prediction model and its solution method are proposed based on crescent-shaped wear morphology and wear-efficiency model. Besides, strength degradation of worn casing is analyzed in bipolar coordinate system and the model is verified by finite element method. Therefore, the technology of casing wear prediction and residual strength evaluation is completed systematically. Then, to apply casing wear prediction and residual strength evaluation technologies to an actual highly-deviated well, casing wear experiment and friction coefficient experiment are carried out to obtain wear coefficient and friction coefficient. Finally, based on the established models as well as experimental results, the distribution of casing wear is predicted and residual strength is evaluated. The method presented in this paper will contribute greatly to casing wear prediction and evaluation in highly-deviated wells.

套管磨损是大斜度井中的一个严重问题，严重磨损会导致套管变形、钻具卡钻以及后续作业的失败。本文的目的是预测大斜度钻井作业中套管磨损深度并评估其对套管强度退化的影响。特别关注实现预测和评估的算法。接触力模型考虑了钻杆接头对接触力分布的影响。然后提出了基于月牙形磨损形态和磨损效率模型的磨损深度预测模型及其求解方法。此外，在双极坐标系下对磨损套管的强度退化进行了分析，并通过有限元方法对模型进行了验证。从而系统地完成了套管磨损预测和残余强度评估技术。然后，将套管磨损预测和剩余强度评估技术应用到实际大斜度井中，进行套管磨损实验和摩擦系数实验，获得磨损系数和摩擦系数。最后，根据建立的模型和实验结果，预测套管磨损分布并评估剩余强度。本文提出的方法将对大斜度井套管磨损预测和评估做出巨大贡献。