井口套管磨损失效原因分析及预防措施

Failure analysis and preventing measures for casing worn out at well head

许峰 吕拴录 康延军 杨成新 李怀中 秦宏德

XU Feng LV Shuanlu KANG Yanjun YANG Chengxin LI Huaizhong QIN Hongde

江汉石油管理局第四机械厂，湖北荆州　434000 中国石油大学机电工程学院材料系，北京　102249 塔里木油田勘探开发部，新疆库尔勒　841000

SJ Petroleum Machinery Co., Jingzhou, 434000, China Mechanical and Electrical Engineering Institute of China University of Petroleum, Beijing 102249, China Exploration &

套管磨损，特别是井口套管磨损是油田普遍存在的问题。井口套管磨损失效与井口偏心、井口悬挂载荷、套管头结构、钻井工艺参数、套管材质等有关。对S油田井口套管磨损失效事故进行了研究，分析了井口悬挂载荷和套管头结构等对井口套管磨损的影响。通过对井口套管悬挂载荷的计算，得到了能有效减小井口套管总载荷的优化计算公式。采用该公式对S油田进行了固井施工案例计算，结果表明，按照该公式确定井口悬挂载荷有利于防止井口套管失效。采用Ansys有限元分析软件对套管受卡瓦夹持力的影响进行了研究，研究表明，在卡瓦牙板上、下端面位置套管内表面存在应力集中，提出了套管头卡瓦优化设计方案。

Casing worn out, especially worn-out at well head is a common problem in all of the oilfields. The casing damage at well head is related to the wellhead eccentricity, hanging load, casing head structure, drilling technical parameters, casing materials and so on. This paper gives an investigation on casing worn out at the well head of some oilfield, and analyzes mainly the effect of well head hanging load and casing head structure on casing worn out at well head. The optimization calculation formula for decreasing the whole casing hanging load effectively is given by calculating and researching well hanging load. The formula is applied to calculate casing hanging load in actual well cementing, and the results show that the calculated hanging load is benefit to prevent casing failure at well head from. Finite element analysis software ANSYS has been used to study the influence of slip force on casing, and it found that the stress concentration located at casing inner surface position where the two ends of slips, and optimization of designed slips is suggested.