FUGRO ROTV INSPECTION - · PDF file Multibeam Echosounder • High Resolution Vessel...
Transcript of FUGRO ROTV INSPECTION - · PDF file Multibeam Echosounder • High Resolution Vessel...
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Fugro Survey Ltd,
Overview of acoustics pipeline inspection techniques. A discussion on the current techniques being employed for non visual
pipeline inspection.
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Introduction
• Overview– Side Scan Sonar– Pinger
• Platforms– Near shore– ROTV – Focus-2
• Enhancements and Data Quality• Processing and Interpretation
• High Resolution MBE– Additional Benefits– Products
• Future
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Geophysical Tools
• SSS– Primary Tool
• Detection of Exposures, Damage, Spans, Debris, Position– Mounted on
• Tow fish• ROV• ROTV
• Pinger (Sub Bottom Profiler)– Depth of Burial– Mounted on
• Hull of Vessel• Tow fish
– Lateral crossing of pipeline• Key components of risk based inspection regime • Often first phase of pipeline inspection, flowed by Visual Inspection programme
– ROV Based
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Near shore Pipeline Inspection
• Near shore - Shallow Water –– ROV not practical– ROTV not practical– Typically small vessel with free tow SSS fish – Tow fish positioning by logged cable layback from stern– Or small USBL system– Also high resolution MBE
• Can be limited in shallow water due to survey offset from pipe
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ROTV for API
• FOCUS 400 Remotely Operated Towed Vehicle (ROTV) introduced in 1995
• FOCUS 1000 and 1500 used by other contractors• ROTV used extensively for North Sea pipeline inspections. • Typically used as a SSS platform, • Typical Fugro annual inspection distance in excess of 6000 kilometres• New vehicles in 2006 FOCUS-2…. In use by a number of contractors
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FOCUS-2
• Based Upon FOCUS-400 experience– 100+% Redundancy
• 2 Vehicles – HOT SWAP• 2 Tow cables• Plus additional spares
– Minimal Downtime – Maximum Utilisation– Fast Results
• 400m Depth Range• Fibre Optic Tow Cable• State-of-the-Art Technology…
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FOCUS-2 Technological Advances
• Carbon-Fibre Body– Lighter, Stronger– More Manoeuvrable
• Enhanced Man Machine Interface– Auto Pilot tools
• Follow Pipeline• Maintain Altitude, Offset
• Fibre Optic Multiplexer– High Bandwidth
• Increased Payload Diversity…
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Acoustic Pipeline Inspection Payload
• Digital Side Scan Sonar– EdgeTech Full Spectrum 4200– 410kHz 50m Range– Improved Image Resolution
• Fibre-Optic Gyrocompass (Heading Sensor)– Oceantools MiniFOG– Pitch and Roll– Improved Positioning Accuracy
• Altimeter• Depth Sensor• USBL Responder• Optional
– Multibeam Echosounder– Doppler Velocity Log
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Data Example - Exposed Pipeline
ROTV Advantages:
Stable Vehicle
Quiet Platform
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Data Examples – Rock Dumps
ROTV Advantages:
Optimum Position
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Data Examples - Structures
SSIV
Valve Prot.
ROTV Advantages:
Optimum Altitude
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Data Examples – Pipe Displacement
ROTV Advantages:
Rapidly Manoeuvrable
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Data Examples – Weightcoat Damage
ROTV Advantages:Onboard Gyrocompass
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Data Examples - Debris
ROTV Advantages:Speed of Survey3 ½ - 4 Knts140-160km/day
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Improved Positioning
• MiniFOG provides true heading information on ROTV • Sonar interpretation is corrected in processing to produce
accurate pipe event positions
• Partnered with accurate USBL and HP Surface positioning– (HiPAP and StarfixXP/HP)
If the difference between Heading and CMG (tow direction) is 20°, at 20m range this would produce an error of over 7m
With a FOG fitted we see severe changes in heading - 40° in less than a minute
FOG Heading
CMGROTV
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Processing and Interpretation
• Core of specialist personnel– Senior Geophysicist – Interpretation Team Leader
(3-4 years experience, 70 - 100 days/year inspection)– Three Geophysicists– Senior Surveyor/Data Processor – Processing Team Leader– Two Data Processors
• Annual training course involving all key personnel• Company training manuals for interpreters/data processors• Annual 6 month programme in North Sea• On-going development programme
– Efficiency– Enhancements
• Exports to Asset Management systems
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Optimised Interpretation Software
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Data Management
Database for Status Tracking
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Result Presentation - GIS
• Data lends itself to display in GIS• Primary 2D data
•ArcGIS the most popular format for the oil and gas Industry
•Products supplied in geo-referenced databases with attributes for further query
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Result Presentation - Charts
• Automated Chart Production Tools• Year on Year comparison
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Multibeam Echosounder
• High Resolution Vessel Mounted MBE – Reson 8125, EM710
• Shallow Water solution to provide additional information about the situation of the pipeline and the surrounding seabed. Increased depth range with systems like EM710.
• Additional Tool for determination of Pipe position– Increased position certainty - surface sensor
• High resolution bathymetric model of seabed including pipeline.– Cross Profiles
• Or ROTV Mounted MBE ( EM3002)• ROTV geometry not ideal for acquisition of MBE during SSS
phase
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20m
50m
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MBE – Pipeline in its surroundings.
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MBE – Pipeline in its surroundings.
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MBE – Pipeline in its surroundings.
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MBE – Pipeline in its surroundings.
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Result Presentation - MBE
• Incorporating– ROTV– MBE– Pinger
• Presenting– Contours– Shaded Relief– Cross Profiles– Plan Events– Seabed Profile– Depth of Burial– Pipe Status
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Eyeball ROV on Acoustic Inspection Vessel
• Spot Dives on critical events from ROTV survey as identified• Small Sections of GVI / CVI • Digital Stills Photography• CP (Contact, Proximity & Field Gradient)• One vessel, one mobilisation, fast results…
Inspection
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Future Developments
• Synthetic Aperture Sonar (SAS)– Increased resolution
• Automated processing tools– Pipe detection
• MBE Backscatter– Hull mounted and ROV based.– Typically around a 20 fold increase in data volume– Tool for detection of pipe position, automated
• AUV ?• ROTV positioning
– DVL– INS
• Presentation tools– Raw data viewer with results for Operator
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Summary
ACOUSTIC INSPECTION SURVEYS• Accurate delineation of pipeline position• Accurate Event Listings• Higher resolution survey data• Fast Results• Reduced Vessel Mobilisations• Reduced ROV Inspection Scope
• Limitations– Burial
• limited to pinger crossings• Additional phase of survey
– One pass operations are offset from pipeline