Blockage detection techniques for natural gas pipelines: A review

Liquid and hydrate blockages often occur in natural gas pipelines, reducing pipeline transportation efficiency. When blockages completely occupy the pipeline, major production and safety accidents can occur, such as production shutdowns and overpressure damage. This study comprehensively describes in detail the technical principles and characteristics of 12 natural gas pipeline blockage detection methods and lists the challenges they face in practical applications. Moreover, common techniques for eliminating blockages in gas pipelines are presented. Then, whether the different detection techniques can realize the five functions of blockage quantity, blockage location, blockage length, blockage area, and continuous detection is theoretically discussed. Furthermore, the advantages, disadvantages, and limitations of different detection techniques are evaluated from six aspects: detection speed, accuracy, adaptability, anti-interference, impact on pipeline operation, need for historical information, and cost. Transient wave reflection and inverse transient analysis methods deserve more studies in this field. Finally, recommendations for future work are presented based on five aspects: morphology and number of blockages, acquisition of initial pipeline parameters, remote detection, signal processing, and blockage media. This study serves as a useful tool for gaining insights into recent advances in natural gas pipeline blockage detection methods.