Current status and prospect of inline inspection technologies for defects in girth weld of oil and gas pipeline

In recent years, incidents related to cracking of girth welds in oil and gas pipelines occurred frequently. Accordingly, inline inspection technologies for defects in girth weld attracted extensive attention. Through reviewing of domestic and overseas incidents involving such cracking and relevant causes, it is found that most of the incidents were caused by defects such as cracks, incomplete penetration and incomplete fusion and sharp undercuts, and these defects often occurred on inner surface of pipelines. With highly concentrated stresses, these defects may significantly reduce bearing capacity of pipelines. This paper reviews the current status, features, limits, future development and directions of four detection technologies for defects in girth weld, namely, magnetic flux leakage testing, ultrasonic inline inspection, electromagnetic ultrasonic inline inspection, and electromagnetic vortex inline inspection. Relevant research results may provide some solutions to technical challenges related to inspection of girth weld in oil and gas pipelines.