Decommissioning operations have to be carried out in accordance with strict guidelines. Because these projects can be costly, expediting the cleanup process is the operator’s goal.The challenge is to perform the work rapidly without compromising safety or the quality of the work.
On a decommissioning project in the North Sea in May 2011, operator ConocoPhillips needed to remove old debris from a 250-m by 250-m (820-ft by 820-ft) area in preparation for the installation of a new platform. The site, which had been in use for 30 years, lies 322 km (200 miles) southwest of Stavanger near the border between the Norwegian and UK sectors of Ekofisk, the oldest field in the North Sea.
PanGeo Subsea was contracted to carry out a post-debris clearance survey with the Sub-Bottom Imager (SBI) (see photo above with SBI aunched from a pipelay vessel to carry out imaging of a buried pipeline in the North Sea.) an acoustic survey tool that uses an array of five hydrophones with 40 channels, to create a 5-m (16.4-ft) deep by 5-m wide 3-D volumetric image of the sub-seabed.