bpp gjl spim 07dec12 - subsea uk

Inspec'on of Flexible Risers – What the Future Holds

Geoff Lyons (BPP-‐TECH)

Subash Sood (CIT)


Reference is made to Ultrasonic, Eddy Current, Radiographic other technologies and considers how these can most reasonably be used with existing and future assets. The presenters’ particular experience with radiographic inspection of !exible risers is highlighted. The presentation considers how these technologies may be coupled to real-time load/stress sensing within the riser including strain and acoustic emissions sensing, and what these can really deliver.


Examples of in-service monitoring and examinations are provided graphically demonstrating the bene"ts of the various approaches. These are particularly related to the presenters’ experience along with reference to key data from other sources.


A discussion of how some of these technologies can be transferred to other subsea assets is included, relating principally to tensioned risers, SCRs, umbilicals, power cables, and seabed !owlines.

Opera'onal failure mode overview

Progressing from outside

•  Wear from interfacing structures (arch, GT, bend stiffener) •  Wear of fabric tape •  Dropped objects •  Interference with structures •  Entanglement with other lines •  External sheath breach •  Aging •  Corrosion •  Hydrogen Induced Stress Cracking (HISC)

Source: 4Subsea HES: UK Industry Seminar Integrity management of unbonded !exible pipelines 27 November 2008

Opera'onal failure mode overview

Progressing from inside

•  Carcass fatigue •  Carcass collapse •  Erosion •  Temperature cycling fatigue •  Ageing

• Chemicals • Temperature • Water

•  H2S/CO2 diffusion •  Armour fatigue •  Vent system malfunction (external sheath breach)

Source: 4Subsea HES: UK Industry Seminar Integrity management of unbonded !exible pipelines 27 November 2008

Inspec'on of Flexible Risers – Monitoring possibili'es

•  CP tests •  Annulus vacuum tests •  Flooded member testing •  Laser Leak Detection •  Tether monitoring •  Bend stiffener strain measurement •  Bend stiffener location curvature and tension monitoring •  Subsea annulus vent monitoring •  Bend stiffener sonar measurement •  I-Tube camera •  Vibration monitoring •  Polymer degradation •  Produced sand monitoring •  Riser !ushing checks •  Vessel transit •  Dropped object reporting •  Fibre optic monitoring

Source: MCS HSE: UK Industry Seminar Integrity management of unbonded !exible pipelines 27 November 2008


Technologies highlighted: • Strain Sensing (Electrical and Fibre optic) • Leak detection (!ooded annulus) • Metallic corrosion and breakage:

Ø  Ultrasonic Ø  Eddy Current Ø  Radiographic

• Inferential: o  Vessel motions o  Waves o  Current


Developments from several JIPs: •  FlexiRiser •  DRIFT •  Riser End of Life (REL) •  HOIS

Inspec'on of Flexible Risers – earlier HOIS Trials

The MAPS-FR technique was the most successful of the HOIS trials, detecting individual and multiple broken armour wires remotely. • Microwave inspection and to a lesser extent shearography showed promise. • Most methods had practical limitations • Several methods including thermography and shearography had difficulty in seeing through the outer polymer layer and most could not see beyond the "rst armoured layer • The trials on the MSS guided wave method (as used on wire ropes) were less promising than hoped. The signal was heavily attenuated by the outer polymer coating. Range achieved in practice unlikely to exceed 3m. Sensor strips need to be preinstalled below the outer polymer layer. • Electromagnetic methods, acoustic emission (AE) and high energy radiography seem the most promising of the methods trialed separately by HOIS members

Source: HOIS UK Industry Seminar Integrity management of unbonded !exible pipelines 27 November 2008

BPP AE and Bending Emerald Producer flexible riser

Inspec'on of Flexible Risers – Ultrasonic

Ultrasonic (AGR) Tools available for detecting !ooding of annulus and thickness of outer (tensile armour) wires Thickness measurement requires annulus to be !ooded (water as a transmission medium) High resolution thickness measurement – useful for corrosion assessment – but very slow

Magne'c/Eddy Current Inspec'on

Innospection/Fugro (MEC-FIT) technique combines the direct-current-magnetic-"eld-lines with eddy-current-"eld-lines, allowing the deeper penetration into the ferrite steel material. Relatively fast – but requires same riser specimen for proper calibration. Deployed by ROV

MAPS Static location near top of riser – externally mounted; no penetration through outer !exshield layer – detection of fatigue failure in end termination – detection of corrosion/fatigue in tube/splash zone – Detection Range ± 20m from monitor – positioned at base of bend stiffener, remains fully functional into termination

Inspec'on of Flexible Risers – Radiographic Inspec'on

DRIFT/FlexiRiser (CIT/BPP-TECH) What you see is what you’ve got

Flexible Risers and SCRs CIT/BPP Radiographic Imaging

CIT TWI

High resolution to 3000m


Loss of interlock shown here in this riser was as a direct result of the recovery method used to remove the riser from the mid-water arch None of the risers used in the Riser End of Life JIP failed in service !!!

A very clear example of loss of interlock shown by CIT/BPP


The equipment resolution which was available during the REL inspections was 100 microns (0.1mm), from which it was seen from the Image Quality Indicator that 800 microns (0.8mm) was detectable. This very high resolution is one of the signi"cant advantages of radiographic inspection Note that CIT/BPP have CR equipment with even higher resolution (50 microns, 0.05mm) available This technology is suitable for:

•  Crack detection •  Corrosion (detectable in width at present – possibilities for

depth in future) •  Loss of interlock

BPP-‐TECH Foinaven FPSO long term bend s'ffener/umbilical

stress monitoring

BPP-‐TECH Foinaven FPSO long term bend s'ffener/umbilical

stress monitoring

min/mean/max!

rms - mooring freq!

rms - wave freq!

rms - VIV1: 0.5 - 2 Hz!

rms - VIV2: 2 - 10 Hz!

mean current!

Tensioned Risers (BPP-‐RMS Riser Management System)

The technologies described have application also with SCRs, umbilicals, power cables, and seabed !owlines


•  Mature and maturing sensing technologies •  No single technology sufficient – need a combination

•  Advanced signal processing and data handling capabilities available


www.bpp-tech.com

London Aberdeen Singapore Houston

www.cituk.com

Milton Keynes

bpp gjl spim 07dec12 - subsea uk

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