Abstract: The safety problems of oil and gas pipelines will cause serious damage to the national economy and social security. Girth weld failure, as one of the main failure modes of high-grade steel, large-diameter, long-distance natural gas pipelines, poses serious risks. Therefore, regularly conducting precise and effective internal inspections is a crucial measure to ensure the safe operation of long-distance natural gas pipelines. To address the needs for detecting circumferential weld failure risks in large-diameter natural gas long-distance pipelines, this study proposes an ultra-high-definition magnetoelectric composite in-line inspection gauge. The inspection gauge integrates magnetoelectric composite sensors, alternating magnetic field stress measurement sensors, and caliper sensors, forming a multi-physical field pipeline inspection system that combines multi-dimensional sensing, circumferential seamlessness, and ultra-high axial resolution. Its detection accuracy and reliability have been detected by both laboratory tests and field trials on the equipment. The experimental results show that the equipment can detect Φ3 mm pinhole defects, 0.3 mm open girth weld cracks, and 1 mm wide minor girth weld defects in pipelines. Moreover, it achieves a detection rate as high as 94.4 % for small and complex defects. The equipment has successfully realized the industrial application of additional stress internal inspection for high-grade steel and large-diameter long-distance pipelines, as well as effective defect identification. To some extent, it fills the technical gap of large-diameter natural gas pipeline internal inspection devices in China, and has certain significance for improving pipeline operational safety.

Key words: natural gas pipeline, in-line inspection gauge, girth weld failure, multi-dimensional sensing, circumferential seamlessness, ultra-high axial resolution

摘要： 油气管道发生安全问题会对国民经济及社会安全带来严重损害。环焊缝失效是高钢级、大口径长输天然气管道失效的主要形式之一。因此,定期实施精准有效的内检测作业是保障长输天然气管道安全运行的重要措施。针对大口径天然气长输管道环焊缝失效隐患的检测需求,提出了一种超高清磁电复合内检测器。该内检测器整合了磁电复合传感器、交变磁场应力测量传感器以及测径传感器,构建了一套集多维感知、周向无缝、轴向超清于一体的多物理场管道内检测装备。通过对该装备开展实验室测试与现场试验,验证了其检测精度与可靠性。实验结果表明,该装备能够检测管道Φ3 mm的针孔缺陷、开口为0.3 mm环焊缝裂纹以及宽度为1 mm的环焊缝微小缺陷,且对微小复杂缺陷的检出率达94.4%。该装备实现了高钢级、大口径长输管道附加应力内检测工业应用和缺陷的有效识别,能在一定程度上弥补大口径天然气管道内检测器的技术短板。

关键词: 天然气管道, 内检测器, 环焊缝失效, 多维感知, 周向无缝, 轴向超高清