Subsea Condition Monitoring - Subsea UK

subseauk.com

Subsea Condition Monitoring - Subsea UK

Subsea 7

Dr Gordon Drummond

1-Mar-13

Page 1


Subsea Condition Monitoring

Subsea 2013;

Dr Gordon Drummond


AGENDA

• Drivers for Subsea condition monitoring

Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

1-Mar-13

Page 3


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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Page 6


AGENDA

• Drivers for Subsea condition monitoring

Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

1-Mar-13

Page 7


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


Deploy

surveillance

techniques

that seek

infant

mortality

Monitor age related

failures by increasing

inspection frequency

to ½ x (remaining

life).




Pigging campaigns



Continue to monitor, stepping out the inspection

interval to N+1, if no anomalies found





0 1 5 10 15 20 25

22.5 23.75

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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.

Early infant

mortality +

random

Random + Fatigue

Tradition bathtub

Early infant

mortality + fatigue

Increasing failure

rate w.r.t time

Random failure rate

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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Page 11


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 Buckling

∆ε

X

Z

Y

Upheaval Buckling

∆ε

Lateral pipeline buckle

Y

x

Z

Upheaval Buckling

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Impact – “Dropped Object”

∆ε

Gouge

Pipeline impact damage

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

Impact,

26%

Corrosion,

40%

Fatigue

Low

Other, 17%

Material,

15%

Structural,

2%

1-Mar-13

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AGENDA

• Drivers for Subsea condition monitoring

Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

1-Mar-13

Page 20


Solution – Phase I - Greenfield Pipe-in-Pipe

Insulation Blanket Sleeve Pipe Flowline

Fibre Optic – Axial Stress

Fibre Optic – Temperature

Fibre Optic – Hoop Stress

Annulus

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

Clamp

Flowline

∆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

1-Mar-13

Page 24


AGENDA

• Drivers for Subsea condition monitoring

Condition monitoring

• Overview of the failure modes

• Looking ahead

• Summary

1-Mar-13

Page 25


seabed-to-surface

www.subsea7.com

1-Mar-13

Page 26

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