Inline inspection in subzero temperatures
Inspecting and maintaining sub-surface pipelines is a challenging task – even more so when the pipeline is located offshore in turbulent seas and in subzero temperatures…
Maintain a pipeline network to the most rigorous standards of productivity and safety requires regular inspections to generate a comprehensive picture of the condition of the line. The more complex and isolated the pipeline network, the more complicated this task becomes.
In the Bohai Sea, 375 km southeast of Beijing, a lattice of pipelines stretching a total of 21.4 km connects six platforms. To ensure that inline inspection of these lines was executed efficiently, while generating the greatest amount of useful data, a major operator called upon global pipeline service provider T.D. Williamson (TDW) to help locate and identify threats to pipeline integrity.
The operation – which included pre-cleaning, deformation inspection, and magnetic flux leakage for corrosion detection – consisted of five separate pipelines, varying in diameter. The lines also varied in length, from 2.11 to 9.10 km. Three of the lines necessitated Light Geometry Tool (LGT) and Gas Magnetic Flux Leakage (GMFL) runs, while the other two required only GMFL. In most cases, the runs were completed within one week, meeting the operator’s need for minimal downtime. Upon completion, tools were mobilised to the other platforms for additional runs. Pressure in the lines was maintained at a steady level between 81 and 88 bar.
All work was completed without incident and within five months. Data was validated and analysed before being forwarded to the operator for review and assessment.
Relying on TDW inspection technology to collect a wide variety of data, as well as expert analysis of that data, the customer was then able to assess the condition of each line and to formulate appropriate maintenance plans.
The operator’s proactive approach to pipeline integrity continues to ensure the extended life and productivity of its assets.>
Source: Control Engineering Europe - All Articles