recent advances in riser monitoring systems · 2017. 2. 27. · scr trench parted drilling riser....
TRANSCRIPT
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Recent Advances in Riser Monitoring Systems
Shreenaath Natarajan2H Offshore
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Riser and Conductor VIV
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Why Monitor RisersRisers are fatigue critical structures
Complex interfaces at the vessel and the seabed
Multiple assumptions involved in design data and methodologiesRiser failure is totally unacceptable
Courtesy: SPE 2005SCR Trench Parted Drilling Riser
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Riser Monitoring System Design
Monitoring PurposeEnvironment / Vessel motion induced riser responseRiser/soil interactionSpecific component performanceCapture uncertainties in extreme event responseFatigue concern
Suitable instrumentationData processing requirementsData communication requirements
Real time / quasi-real time / log & retrieve
CostInstallation
Retrofit / Pre-installation / during riser installation
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Recent Achievements
Cost-effective subsea strain sensorAcoustic data transmissionSubsea microphone based flexible armour wire monitoring
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Strain MeasurementFeatures
Conventional electrical foil strain gauges in pressure balanced cylindrical tubeBending strains along 2 planes3 micro-strain accuracy
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Strain MeasurementBenefits
3000m depth rating Conventional electrical foil strain gauges are restricted to above surface / near surface
High resolution suitable to capture small strains causing riser fatigueExtremely low power consumptionSuitable for both standalone and real-time applicationsCheapest strain gauge option for subsea application
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GoM Tahiti SCR Real Time Monitoring System
5 Strain and Motion Sensors Top
11 Strain and Motion Sensors TDZ
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Acoustic LoggingFeatures
Acoustic transponder and sensors powered by self-contained battery unitAcoustic receiver on deck Software to process and display on-boardLow power and high precision accelerometer/inclinometer arrangementElectronics adaptable for any type of measurements
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Acoustic LoggingBenefits
Acoustic link enables data communication near quasi-real timeReduces complex cabling and risk of damaging the cablesLow power electronics minimizes power consumptionAcoustic link enables data logger switching on/off as required, maximizing the battery lifeProvides easy retrofit options using ROV/diverOff the shelve monitoring product
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Mooring Line Monitoring System
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Shell BC-10 Mooring Line Monitoring System
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Flexible Riser Monitoring Features
1D Axial acceleration sensor2D Angle rate and inclination sensorsMicrophone
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Laboratory Tests
Flexible riser on a test rig to maintain static tension and apply dynamic tension cyclesArmour wires cut initiated using hand held tools
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Laboratory Test Results
All 30 wire break tests are recorded by the instrumentation package
Acceleration Microphone
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Offshore TestsInstalled near the bend stiffener to measure the background offshore noise detectedArmour wire break noise is clearly distinguishable compared to:
Background noiseImpact due to dropped objects or collision
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Flexible riser monitoring system
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Conclusions
Low power and more reliable electronicsHigh resolutionCost effective
Acoustic transmission reducing complex cablingReduced risk of cable failure compared to a hardwired systemInstrumentation is away from critical path of installationField proven technology
Novel concept turned in to a realityCapture flexible riser response near critical riser-vessel interfaceEarly identification of armour wire rupture