Empirical Study of Magnetically Operated PIG for Cleaning of Subsea Pipelines
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The objective of this Master?s Thesis has been to verify several aspects of the EMPIG flow assurance system through functional prototype physical testing. Summaries of key findings, with reference to focus area, methods and results, are included in this abstractMagnetic lock force28 physical tests were performed with the intention to investigate the magnetic lock force connection between the magnetic sled and PIG using two PIG concepts. This resulted in an axial magnetic lock force of 1719 N for the passive PIG, and 2655 N for the active PIG concept. The results of the analysis study performed in the Project Thesis, written the autumn of 2012 , showed that the passive- and active PIG potentially produce a lock force of 1801 N and 3938 N respectively. The result of the analysis study and the physical tests were found to be especially similar for the passive PIG concept.Wax layer removal32 physical tests were performed with the intention to investigate the cleaning efficiency and scraper resistance of the seven tested scraper designs. A 1 mm paraffin-wax-based deposition layer was added to all test pipes. The scraper resistance results were found to be in the range of 90 N ? 1200 N with equally large variations in cleaning efficiency. Compared to the magnitude of the magnetic lock forces, the scraper resistance was not considered to be an issue.Full system testingA flow loop was designed and built in order to directly investigate if a 1 mm wax deposition layer could be removed using only the magnetic connection between the magnetic sled and PIG. The test was successful.Based on the results of this thesis, the EMPIG system was found to be feasible for both the passive- and the active PIG concept.