Survey Interceptor Remote Operated Vehicle (ROV) completed its first commercial mission in March 2015 for the natural gas pipeline operator Gassco. The ROV inspected the external condition of the Knarr Gas Pipeline and the rock berm protection.
Kystdesign built the Surveyor Interceptor ROV for the joint venture (JV) between Reach Subsea and MMT Sweden. The ROV acquires stable data at high speed via a totally new technology used by Survey ROVs (SROVs) that generously cuts inspection cost and time.
Since March 1, 2015, Gassco is the official operator of the Knarr Gas Pipeline. The Knarr Gas Pipeline Joint Venture owns the 12inch pipeline that possesses a technical capacity of 1.7million standard cubic meters per day.
Located about 100km north of Statfjord in the northern part of the North Sea is the Knarr Oil and Gas Field. The Knarr Gas Pipeline will supply gas to St. Fergus, Scotland via the Far North Liquids and Associated Gas System (FLAGS) and the Shell-Esso Gas and Liquids System (SEGAL).
Rock Berm is a rock embankment that prevents the inflow or outflow of material from an area. Underwater rock berms improve the lateral resistance of pipelines to buckling and protect pipelines against possible damage from dragging anchors and hydrodynamic loads created by waves and currents.
Rapid & Reliable Inspection
Inspecting the Knarr Gas Pipeline along 106km of its length, the ROV comfortably traversed water depths of 140-400m and completed the inspection in just 17hours, three times faster than a conventional ROV would. It logged an average speed of 3.33knots and top speed of 4.5knots.
Deployed from the Edda Fonn, the Surveyor Interceptor was stable throughout the operation. The ROV executed the exercise in one go and acquired high quality data. It swam 4-5m over the pipeline to conduct the multi-beam SONAR survey with a 0.1m grid size to collect a full 3D photomosaic.
- Fast, Accurate, and Stable with High Resolution\
- Two Main Inspection Modes and One Manipulator Skid. Main Inspection Modes:
‘high fly’ high speed acoustic pipeline surveys
‘low fly’ full three camera inspection in known problem areas
- Can be operated:
with tether management system
in free swimming mode
with special umbilical handling system
- Combines Ultra-Short Baseline and Inertial Navigation aided by Doppler with data acquisition through fiber-optic interfaces and real-time quality control
Inertial Navigation System (INS) is navigation utilizing dead reckoning that uses computers, rotation sensors, and motion sensors to calculate the direction and speed of movement of mobile objects
Dead Reckoning finalizes an object’s position based on its previous position and the direction plus speed of subsequent travel
Ultra Short Base Line (USBL) employs acoustic signals through a transceiver to detect the distance and direction to a target
- Wide Operational Window
- Low Pump and Thruster Noise for exceptional data quality. Earlier trials had provided multibeam data with less than 0.4% noise
- Developed Capabilities of Sensors, Camera, and Lighting for better video and data quality
- ‘Unlimited Power’ because of no batteries
- Easy Interfacing with existing survey vessels
- Compatible with future sensors
After successful offshore trials on Europipe 2 last year, MMT Sweden and Reach Subsea refined the ROV’s cameras and developed a new launch and recovery system capable of operating in sea states of up to 3.8Hs. Earlier trials had also demonstrated an 8knot design speed with high density data acquisition at 6knots when moving close to pipelines.
MMT Founder and Project Director Ola Oskarsson described the 4.5knot inspection speed as a world record and said the Surveyor Interceptor was well capable of reaching inspection speeds of 6knots, 3knots faster than conventional ROVs.
According to Gassco, the Surveyor Interceptor could slash expenditure on submarine pipeline inspection by as much as 30%. These savings will result from the high speed of the ROV and because the ROV is conveniently operated from smaller, cheaper vessels.
It is this potential to massively lower inspection time and cost saving that makes the offshore oil and gas industry eye the Surveyor Interceptor with great interest. Inspection of submarine pipelines is expensive business. The ROV, vessel used to deploy the ROV, ROV technology, and ROV efficiency determine the total cost of inspection.
Gassco is particularly delighted with the Surveyor Interceptor for the company operates the Gas Transport System that delivers Norwegian gas to the U.K., and continental Europe via pipeline of over 8,000km length. And, most of Gassco’s pipelines are located on the ocean floor.
Oil and gas explorers are moving into deeper, more perilous waters to quench our thirst for energy as older fields reach the end of their lifecycles. Pipelines in such water face newer and more lethal threats. Inspecting these pipelines with conventional ROVs may not be technically and financially viable. Thank God, we have the Surveyor Interceptor!