Detection of hydrate and other blockages in gas pipelines using acoustic reflectometry

This article describes the application of an acoustic reflectometry technique to detect blockages in long lengths of gas-filled pipelines. The use of the technique in laboratory pipelines has been previously reported. However, in this article, the technique is applied to a series of pipelines that provide the ideal test bed to thoroughly assess the capabilities of using acoustic reflectometry to detect and locate defects in industrial gas-filled pipelines. In particular, the use of the technique for detecting the early formation of hydrates in subsea pipelines is evaluated. Four very different pipelines were used for this evaluation. These pipelines varied in inside diameter from 0.06 to 0.6 m, were operated at pressures of up to 10 MPa and contained both flowing and static gases. In all tests, the acoustic reflectometry technique was able to accurately detect and locate the blockages within the pipeline. The results suggest that acoustic reflectometry is capable of detecting full and partial blockages in pipelines with lengths of up to 10 km.