Scope of work
N-Sea successfully completed a multidiscipline scope for Gas Networks Ireland formerly known as Bord Gáis Networks. Gas Networks Ireland owns, operates, builds and maintains the natural gas network in Ireland and connects all customers to the network. The 13,000km pipeline network delivers a safe, efficient and secure supply of natural gas to 673,000 homes and businesses, 24 hours a day, 365 days a year and is linked to the UK and European gas markets through two interconnector pipelines with Scotland.
The scope of work on Gas Networks Ireland’s offshore pipelines was perfectly suited to N-Sea’s credentials as an iIMR contractor, and consisted of a high speed ROTV pipeline inspection, which included an “on the spot” data interpretation to allow identified monitor items to be inspected by WROV without any delay. N-Sea also undertook intermediate maintenance/repair following the survey in the form of debris removal and stabilisation by rock dumping.
In addition, N-Sea was tasked with the inspection of some predefined anodes, in order to calculate the remaining degree of electro-chemical protection afforded to the pipeline. All three anodes were located where the pipeline was buried up to a depth of one metre and through use of N-Sea’s Mass Flow Excavation tool (MFE), the layer of sand and gravel on top the anode was carefully removed. The MFE allows a fast and controlled excavation of the pipeline with mounted survey equipment such as motion sensor, multibeam and USBL making it possible to excavate on top of the anode without the risk of creating either a freespan or overdredge.
A similar campaign is scheduled for 2016, when N-Sea will have the potential to deploy another in-house skill as the Isle of Man Tee structure will require diver inspection.