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TRACERCO Diagnostics™

Subsea Pipeline Deposit Survey

Blocked pipelineA subsea 6-inch gas flow line was suspected to be blocked by ‘hydrate’ with an approximate density of 0.98g/cc. A gamma ray transmission survey was used at exposed sections of the pipeline, using an ROV with a fixed yoke scanning system attached. A radioactive sealed source was positioned on one side of the pipeline and the amount of radiation transmitted through it was measured with a radiation detector. The separation of the source and detector was kept constant ensuring that the intensity of transmitted radiation was a function of density of the medium if passed through. Thus, it was possible, from measurement of radiation intensity at the detector and radiation intensity entering the pipe, to determine the density of material in the pipeline. Hundreds of measurements were taken at approximately one-metre intervals along the exposed pipeline, and this approach provided a profile of the amount and location of deposited material within the pipeline.

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