隔热管气密封性能的评价与泄漏原因分析

通过全尺寸试验，研究了我国稠油热采油田注蒸汽用隔热管的气密封性能，这种隔热管在模拟热采井工况条件下气密封性能很差，存在着严重的泄漏现象。指出偏梯形螺纹连接本身存在较大的泄漏通道，是造成泄漏的内在原因；工厂为弥补这一缺陷而设计的密封圈质量较差、密封槽设计不合理，以及所使用的螺纹脂不耐３５０℃高温，是造成隔热管泄漏的外在原因。针对上述泄漏原因，提出选用特殊螺纹套管作为隔热管的外管，研制新型耐３５０℃高温螺纹脂，改进密封槽的设计及选用质量好的密封圈等三项相应的改进措施。

Gas tightness evaluation and leakage cause analysis of heat insulated tubing

By means of fullscale test, the gas tightness of heat insulated tubing for steam injection is investigated. Under the simulated working conditions of thermal recovery wells, the heat insulated tubing has poor gas tightness leading to serious leakage. It is pointed out that the inherent reason of the leakage is that the buttress thread is adopted, and the outer reasons of the leakage lie in poor quality sealing ring being used, the design of sealing groove being unreasonable, and the thread sealing compound failing at 350. Thereby it is suggested that premium connection casing be selected as the outer pipe of the heat insulated tubing, high quality sealing ring be used, the design of sealing groove be improved, and high temperature proof thread sealer be developed.