P110钢级LC套管螺纹接头内压失效分析

为了研究LC套管螺纹接头密封性的影响因素,对某套管制造企业生产的P110钢级Φ139.7 mm×10.54 mm套管进行了了内压至失效试验。试验结果显示,当试验压力升到69 MPa保压10 min时套管无泄漏,继续升压至83.5 MPa时现场端螺纹接头出现泄漏失效,未达到API TR5C3标准对P110钢级内屈服压力要求(≥93.6 MPa)。对螺纹接头母材理化性能、螺纹接头质量控制、内外螺纹参数匹配、螺纹脂等影响因素的分析表明,上扣扭矩值过小及内外螺纹参数不匹配是本次螺纹接头泄漏的主要原因,最后提出了防止螺纹接头泄漏失效的措施。

Internal Pressure Failure Analysis of P110 Steel Grade LC Casing Pipe Thread Joint

In order to study the influencing factors of the sealing performance of LC casing thread joints, the internal pressure to failure test for P110 steel grade Φ139.7 mm×10.54 mm casing manufactured by some casing manufacturing enterprise was carried out. The test result indicated that when the test pressure rose to 69 MPa and pressure maintaining 10 min, casing did not leak; pressure continuously rose to 83.5 MPa, the leakage failure appeared on thread joints, did not reach the internal yield pressure requirements for P110 steel grade(≥93.6 MPa)specified in standard API TR 5C3. Through analysis on physical and chemical properties of thread joint, quality control, the internal and external thread parameter matching, thread compounds and so on, it showed that too small torque value and the internal and external thread parameter mismatching were the main reasons for thread joint leakage, finally put forward the measures to prevent thread joint failure.