Since 1993, Halfwave and its predecessors have been implementing wide spectrum acoustic resonance inspections to determine the integrity of mainly gas pipelines. This paper shall attempt to outline the advantages of in line inspection using acoustic resonance in comparison to more established inspection technologies such as magnetic flux leakage, and time of flight ultrasonic inspections. The paper will briefly outline ART functionality, past and present use of acoustic resonance, and present in field findings of the technology. The author will then highlight performance validation in laboratory conditions and field validation.
The second part of the paper will focus on a comparison of acoustic resonance and existing ILI techniques. Various aspects of pipeline in line inspection will be highlighted, such as pigging speed, gas flow during operations, pipeline pressure, and pipeline cleanliness. Furthermore, various challenging pipeline configurations will be discussed, such as: multi-diameter pipelines, high wall thickness, bidirectional operations, wye configurations and non-return valves.
An in line inspection for an operator in Australia can be discussed anonymously. This pipeline originates sub sea, and arrives onshore in. For operational reasons, a sub sea ILI tool launch was not a viable option. Considering the above, the decision was made to launch acoustic resonance tool from the on-shore receiver, and pumped into the pipeline using Nitrogen. After it was confirmed the tool had cleared the shore crossing (the most sensitive area), the nitrogen was vented off, and the tool was brought back into the onshore receiver.