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Subsea 7 Dr Gordon Drummond

Subsea Condition Monitoring

Subsea 2013;

Dr Gordon Drummond

3 Page 1-Mar-13

AGENDA

• Drivers for Subsea condition monitoring

• Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

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Drivers

• Philosophy “Design for life”:

Employs redundancy in design Simplicity in design No account taken for failure / scheduled replacement

• Improved understanding of materials and system functionality

Focus on cost and fast track schedule Verified by inspection (Ext) and Pigging / Analysis (Int)

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Drivers

• Requirement to continuously demonstrate “fitness for service” • Removal of deferred production costs associated with pigging • Improved understanding of condition thus improving decision making for de-rating, process optimisation and scheduling for remediation / rectification tasks • Evidence based knowledge to support Field Life Extension and Brown field tie in justifications • Ultimately improved understanding for decommissioning considerations

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Field of the Future

• Subsea Processing • Subsea Boosting • Downhole Separation • Downhole Boosting

Rotating and Reciprocating machinery with moving parts – dynamic machinery

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AGENDA

• Drivers for Subsea condition monitoring

• Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

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Condition Monitoring; how does it differ from routine surveillance tasks?

• Basic need to control hazards to prevent failure and the consequences for

Safety Environment Financial loss

• Deployment of inspection and pigging campaigns will periodically confirm status – it will find faults/ anomalous conditions

• Passive monitoring provides alerts only when threat is truly a danger– it is a measure of health

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Bathtub curve - illustrating inspection points and pigging campaigns

Continue to monitor, stepping out the inspection interval to N+1, if no anomalies found

0 1 5 10 15 20 25

Deploy surveillance techniques that seek infant mortality

Monitor age related failures by increasing inspection frequency to ½ x (remaining life).

22.5 23.75

Pigging campaigns

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Marrying the Inspection technique to failure mode and characteristic

• Describe failure characteristic w.r.t time

– e.g.Totally random failure distribution bearing no relationship to either time or usage.

Random + Fatigue

Random failure rate Increasing failure rate w.r.t time

Tradition bathtub Early infant

mortality + fatigue

Early infant mortality +

random

Low early life failure rate + random failure rate

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AGENDA

• Drivers for Subsea condition monitoring

• Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

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Failure Modes – Static Plant

• General Metal Loss • Mechanical Overstress • Impact • Over-Pressurisation • Fatigue

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General Metal Loss – “Internal Corrosion/Erosion”

∆ε

Grooving corrosion of a water injection pipeline

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Mechanical Overstress – “Spanning”

∆ε

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Mechanical Overstress - “Upheaval/Lateral Buckling”

Lateral pipeline buckle

Lateral Buckling

∆ε

Y

X

Z

∆ε

x

Y

Z

Upheaval Buckling

Upheaval Buckling

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Impact – “Dropped Object”

∆ε

Pipeline impact damage

Gouge

The Sword fish spearing failure mode

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Over Pressurisation – “Blockage/Burst”

∆ε

Hydrate Flow

Removal of Hydrate blockage topside

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Fatigue

∆ε

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Risk

Risk = Probability of Failure x Consequence of Failure Risk rank Failure Modes in accordance with PoF Vs. CoF

• PoF - Statistical data on incidents reported in the North Sea (PARLOC 2001) • CoF – Consequence Matrices (DNV-RP-F116)

Failure Mode Risk

General Metal Loss High

Mechanical Overstress Low

Impact Medium

Over-Pressurisation Medium

Fatigue Low

Corrosion, 40%

Structural, 2%

Material, 15%

Other, 17%

Impact, 26%

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AGENDA

• Drivers for Subsea condition monitoring

• Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

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Solution – Phase I - Greenfield Pipe-in-Pipe

Fibre Optic – Axial Stress Fibre Optic – Temperature Fibre Optic – Hoop Stress

Insulation Blanket

Sleeve Pipe Flowline

Annulus

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Solution – Phase II - Brownfield “Retro-fit” Clamp

Flowline Clamp

∆ε

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Goal

Sensors

Data Acquisition

“Pressure, Temperature

& Strain”

Data Cleansing &

Filtering

Algorithm

“Exceedence Criteria”

Storage

Transmission

“Acoustic, RF or Optical”

AIV Surface Desktop

HARDWARE

PROCESS

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Challenges

• Power • Data Acquisition

Hardwired Wireless

o Acoustic o RF o Optical

Standalone data logging ROV Stab

• Data Processing • Data Storage • Data Retrieval

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AGENDA

• Drivers for Subsea condition monitoring

• Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

26 Page 1-Mar-13

seabed-to-surface

www.subsea7.com