Analysis by Oilfield Testing Services of the three 12-m (39 ft) sections retrieved from the 60-km (37-mi) offshore point in May has led to a recalibration of the predicted internal corrosion. This shows the pipeline’s condition could be considered practically ‘as new,’ IOG said.
The company will now run a crawler-based measurement device from the Bacton gas terminal on the coast to roughly 1 km (0.6 mi) offshore to assess the line’s internal condition, as this is the section that would have been at a higher risk of degradation since the pipeline was decommissioned in 2015.
IOG will use the results to help determine the safe maximum pressure of the subsequent 24-hr hydrotest required under the Pipeline Code.
A further intelligent pigging run will probably not be needed until the line is re-commissioned shortly before first gas from IOG’s hub area developments in the area. By that time, the Thames Pipeline will run continuously from the Southwark platform to Bacton following the addition of a 7-km (4.3-mi) 24-in. extension.
An intelligent pig would then be run to assist future pipeline integrity management along the entire length of the export route.
IOG is now targeting approval for its field development plan for the end of September, after which it expects to start the process of full and safe re-commissioning to allow export of its 303 bcf of reserves from five proven fields and an additional 314 bcf through development and appraisal assets.