西部某油田单井油气集输柔性复合管在服役21个月后发生泄漏。采用宏观观察、几何尺寸测量、红外光谱分析、维卡软化温度检测、硬度测试、拉伸性能测试、密度测试和纵向回缩率测试等方法,分析了该管道泄漏的原因。结果表明:该柔性复合管的运行温度远高于设计温度和内衬层的维卡软化温度,在长期运行过程中,油气介质渗入内衬层和增强层内部,导致管道的承压能力显著下降,管道底部壁厚最薄处首先发生开裂,在内压作用下,管道逐层发生塑性变形,导致管道撕裂,从而发生泄漏。

The flexible composite pipe for single well oil and gas gathering and transportation in an oilfield leaked after 21 months of service.Macroscopic observation,geometric dimension measurement,infrared spectrum analysis,Vicat softening temperature test,hardness test,tensile property test,density test and longitudinal retraction rate test were used to analyze the leakage reasons of the pipeline.The results showed that the operating temperature of the flexible composite pipe was much higher than the design temperature and the Vicat softening temperature of the inner lining layer.During the long-term operation,the oil and gas medium penetrated into the inner lining layer and the reinforcement layer,as a result,the pressure bearing capacity of the pipeline was significantly reduced.Cracks first occurred at the thinnest wall at the bottom of pipeline.Under the action of internal pressure,the pipeline underwent plastic deformation layer by layer,which led to the tearing of the pipeline,resulting in leakage.