This paper discusses pipeline internal deposition mapping and the benefits to operators of end-to-end pipeline internal diameter mapping, the practical application of this unique, nonintrusive technology, and insight about the full technical reach of this diagnostic service.
A pulse of pressure is induced in a pipeline by using the operation of a fast-acting valve closure in the flowing line or by the rapid opening and closing of a bleed valve on a blocked line. The valve closure creates a pulse (similar to a fluid hammer effect) that travels through the medium in the pipeline at the speed of sound. The magnitude of the pulse and the pressure response of the pipeline from the induced pressure pulse as it travels along the pipeline are measured using a high-fidelity, ultra-high resolution pressure transducer and data logger. After processing the data using proprietary algorithms and software, the deposit profile is “mapped.”
A major benefit of the system is that the survey can be used on live pipelines with little or no production disruption. Analysis requires one day under ideal conditions for a preliminary report and a week for final reporting, subject to the particular line parameters at the time of the survey.
For a debris-profiling survey performed in ideal pipeline conditions, the depth of deposit can be identified to an accuracy of 1 mm and the location of the deposit within the pipeline to within 100 m. When performing a blockage location survey, the location of a blockage can be detected to within 0.4% of pipeline length and can be performed on rigid, flexible, liquid-filled, or gas-filled pipelines, subject to a feasibility assessment.