SRD Provides Subsea Visualization at Frigg
SRD, part of the Westhill based Tritech Group, completed an acoustic subsea visualization program in support of decommissioning work on the Frigg field, located on the boundary between the British and Norwegian sectors of the North Sea. In August this year SRD were contracted by Saipem UK's Sonsub Division on behalf of Total Exploration & Production to provide acoustic subsea visualization support. The operation involved the removal and disposal of pipelines within a 500 m radius of the platforms and was conducted from the vessel Normand Cutter. There was also a requirement to smooth the original protective rock berms to remove hazards for subsequent trawling activities. SRD's Subsea Visualisation System (SVS) provided real time monitoring of the smoothing operation and was used for rapid assessment of the dispersal of material. A pair of 240kHz SVS sonar heads was used along with integrated heading, motion and depth sensors. Seabed data was acquired in water depths of 100m using both conventional multibeam and electronic transmit beamsteering techniques. Attention was focused on eight pipelines within a 500 m radius. These routes featured
Bathymetry survey of the whole field area, along with debris locations.
either rock berms covering the pipe or trenches where the pipe had been removed. In both cases, smoothing was required to reduce the severity of the slopes. Using tools within the SVS software, terrain images were produced displaying seabed gradients with a color palette. The images quickly highlighted areas where localized gradient values were outside the pre-determined limits specified.
MacGREGOR Helps Transform Ultra Deepwater Ops
Cargotec's MacGregor has developed technology for handling lightweight fiber rope that offers several advantages compared with traditional steel wire rope, and is about to install the world's first subsea crane to use fiber rope. In January, MacGregor was scheduled to deliver what is reported to be the world's first subsea knuckle-jib crane equipped with a system for fiber rope handling, to be installed on the subsea vessel Havila Phoenix. The 250ton Hydramarine active heave-compensated (AHC) offshore crane is designed with a 250-ton/3,000m single-line winch and is prepared for a 250-ton single-line fibre rope. "MacGregor's technology for handling lightweight fiber rope rather than traditional steel wire rope offers several advantages that will meet the ever-increasing demands of the offshore industry as operators move further into deeper and more remote territories," said Øystein Bondevik, sales director, MacGregor's Offshore division. "For example, due to the neutralization of the weight of the fiber rope in the water, much heavier loads can be handled without strain to the crane at unlimited depths. Consequently, overall safety is improved due to the lighter equipment, which can still carry out heavy work operawww.seadiscovery.com
tions." "The new generation of MacGREGOR Hydramarine subsea technology with operational capacity of up to 600 tons at depths down to 10,000 m ensures indispensable precision, efficiency and safety in extreme conditions during year-around operations," Bondevik said.
Marine Technology Reporter 41
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