Authors:

Giuseppe Giunta

,

Giancarlo Bernasconi

,

Silvio Del Giudice

Publication:

Materials Evaluation, Volume 73, Issue 7

Publication Date: 1 July 2015Testing Method:

Leak Testing

Vibroacoustic sensing is an emerging technique for the detection of leaks and third-party interference on fluid transportation pipelines. The technique is based on the remote identification of fluid transients and pipe shell vibrations produced by any interaction with the pipe or the flow, and transmitted through the conduit. The system performance is a function of the thermodynamic properties of the fluids, which can be mainly separated into liquids, gases, and multiphase mixtures. While liquids are considered incompressible, gases and multiphase mixtures can sustain strong volume variations, thus producing variable flow regimes along the pipeline. This paper analyzes pressure transient propagation in gas filled pipelines. The authors ran field test campaigns in many scenarios, at different pressures, with and without flow, and also in operational conditions, generating controlled interactions with the infrastructure and collecting vibroacoustic signals with a proprietary network of monitoring stations placed along the pipeline. The data were processed to derive pressure transients propagation parameters and detection distances; to characterize the source wavelets with respect to the interference actions (leak, impact, and so on); to analyze the effects of flow and turbulence; to validate mathematical models; and finally to design and calibrate advanced procedures for real-time pipeline monitoring.

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