承插管件连接处涂层的耐蚀性及密封完整性评价

Evaluation of Corrosion Resistance and Seal Integrity of Coating at Joints of Pressure Crimping Pipe

根据西北某油田现场集输管道环境特点,通过高温高压腐蚀模拟试验,水压爆破试验和有限元计算,结合涂层附着力及扫描电子显微镜(SEM)测试对过盈压接管道接头处的涂层有效性和管段密封性能进行评价。结果表明:管道接头处和管体处涂层的表观形貌在腐蚀模拟试验后均未发生明显变化,涂层/基体界面无腐蚀产物出现,管道接头处涂层附着力与管体无明显区别,均高于22 MPa;管段静水压试验失效模式为连接段内外管脱开,最大压力为39 MPa,有限元计算结果与试验结果基本一致,模型可以用于同类管段承压时的受力分析。过盈承插连接方式能够保证接头位置具有涂层完整性和较高的密封完整性,能够满足油田典型集输管道的环境要求。

Based on the environmental characteristics of the field gathering and transportation pipeline in an oil field, the high temperature and high pressure corrosion simulation experiment, hydraulic blasting experiment and finite element calculation were conducted. The coating effec- tiveness and pipe seal performance were evaluated, combined with coating adhesion test and scanning electron microscopy （SEM） observation. Results showed that the morphology of the coating at the pipe joint and the pipe body did not change significantly after the corrosion simulation experiment. The coating/substrate interface had no corrosion products. The difference of coating adhesion between the pipe joint and pipe body was not obvious, both of them were higher than 22 MPa. The failure mode of hydrostatic pressure test was the separation of the inner and outer pipe of the connecting section, and the maximum test pressure was 39 MPa. The finite element calculation showed the similar results, which meant that the model could be used for stress analysis of the pipes with similar pressure condition. The interference fit connection technology of the pipeline could ensure that the coating integrity and the seal integrity were good enough to meet the typical environmental requirements of the oilfield gathering and transportation pipeline.