Rapid Deployment System for monitoring i slugging in subsea pipelines
Agenda Issue Design criteria Design process Operating principles Qualification strategy System description Future applications 2
Pulse Services Structural Data Delivery Services
What and where does Pulse monitor? Offshore wind farms Tidal generators Vessels / platforms Flexible risers Drilling risers Top tensioned risers Free standing risers Steel catenary risers Mooring lines Pipelines
An ACTEON company 5
Problem Installed deepwater pipeline offshore Australia After installation the client became concerned about fatigue life Potential for VIV and slugging impact at buckle initiation sleepers Wanted to measure movement in order to calculate the fatigue life
Types of spans Free spans Unsupported section of subsea pipeline Caused by: local sea bed movement Pipeline profile does not conform to seabed geometry Pipeline sleepers Method of preventing lateral buckling on pipeline However can cause issues due to slugging g Potential fatigue damage to pipeline Vortex induced vibration (VIV) Flow induced vibration (FIV) Onset of scour Tunnel erosion Lee-wake erosion Equilibrium stage U Soil D e U D U D U D S e e W 1 W 2 7
Typical System Layout Current Meter INTEGRIpod SM 8
Free span monitoring system: Data logger Standalone data logger monitoring system Tri axial acceleration Tri plane angular rate External hydrostatic pressure sensor (for direct changes in water depth) The following parameters can be derived: Linear displacement Acceleration due to motion Average Inclination Harmonics Typical battery life of 3 months at 10hz intermittent sampling 9
Free span monitoring system: Current meter Current Meter Measures the speed and direction of ocean currents using the principle of Doppler shift. Battery Operated 20 30min recording per hour Horizontal Upper Lower 2D 3D 10
Mechanical Interface C ROV deployable on structures B Diver deployable on risers A Diver deployable on chains D ROV deployable on structures E ROV deployable on pipelines/risers F Diver deployable on risers
Free span monitoring Relevant Experience Humber estuary pipeline p (UK) 2005 North thsea pipeline span vibration 2009 Pipeline bundle tow out & span monitoring (Malaysia) 2009 Gas pipeline span monitoring (Trinidad) 2010 Gas pipeline span monitoring (Australia) 2012 13 12
Design criteria Client required a system to be: Completely ROV deployable Easy to use Quick to install reducing ROV time/cost Cost effective time and manufacture Deployable at multiple locations 13
Design criteria Design Parameter Clamp design life Installation depth Buoyant weight Flowline diameter Flowline insulation material Outer pipe finish Max pipe pp inclination Max pipe rotation/roll ROV gripper opening distance ROV closing force Value 1 year >1,000m <50Kg 635mm Polypropylene Smooth 5Deg 10Deg 97mm 4092N
Design process Conceptual design Client review Constructability review Prototype testing Qualification 15
Clamp / loggerholder
Clamp / loggerholder 17
Qualification strategy Axial load test Tortional load test Conformation force within capacity of ROVs manipulator Tested on different pipeline diameters and ovality to check range of expected tdtolerances Deflection and structural tests to ensure rugged construction 18
Qualification strategy 19
Operating principles Single point ROV grab bars to operate clamp Adapter developed to suit a range of ROVs ensuring any ROV can install clamp Takes responsibility off the ROV in terms of resulting clamping force Springs with adjustable pre load Stroke limit plates which effect the closed clamp stroke 20
Operating principles Material no corrosion issues no additional cathodic protection required Tough plastic structural part of clamp Softer grade of rubber at contact points to give a higher coefficient of friction All materials 25 years life span subsea without additional protection and degradation 21
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