BEIJING – In the Bohai Sea, a lattice of pipelines stretching a total of 21.4 km (13.3 mi) connects six platforms. To ensure that inline inspection of these lines was done efficiently while generating the greatest amount of useful data, the operator contracted T.D. Williamson (TDW) to locate and identify threats to pipeline integrity. Since the job began in November, temperatures on the offshore platforms dropped as low as -17°C (1.4°F).
The operation – which included pre-cleaning, deformation inspection, and magnetic flux leakage for corrosion detection – consisted of five separate pipelines with diameters of 8-in., 12-in., and 16-in. The lines also varied in length, from 2.11 km to 9.10 km (1.3 mi to 5.6 mi).
Three of the lines necessitated light geometry tool (LGT) and gas magnetic flux leakage (GMFL) runs, while the other two required only GMFL runs. In most cases, the runs were completed within one week. Upon completion, tools were mobilized to the other platforms for additional runs. Pressure in the lines was maintained at a steady level between 81 and 88 bar (1,180 and 1,275 psi).