pipeline span monitoring & flow rate optimization

www.pulse-monitoring.com

Pipeline Free Span

Monitoring: ROI

April 2014


Services Overview

Pipeline Integrity Monitoring

Slugging

• Cyclic stress and inertial

loading cause fatigue

Free Spans

• Potential damage from

VIV, FIV and slugging

• Increasing flow rates

causing enhanced fatigue

FIV

Free Spans


Pipeline Span Monitoring

• Span- unsupported areas of subsea pipeline

• Two types of span that can cause integrity concerns:

– Free spans

– Pipeline sleepers

• Potential fatigue damage from VIV, FIV and slugging

Introduction

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D

e

eS

W1 W2

U

D

U

D

e

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Soil

Onset of scour Tunnel erosion Lee-wake erosion Equilibrium stage


Pipeline Free SpansReducing Operational Costs: Example

0 1 2 3 4 5 6 7 8 9 100

1

2

3

2*|

FF

T| of

x-a

cc.

0 1 2 3 4 5 6 7 8 9 100

1

2

3

2*|

FF

T| of

y-a

cc.

frequency [Hz]

0 0.5 1 1.5 2 2.50

1

2x 10

-3

2*|F

FT

|w o

f x-

acc.

LOGGER NO. T14 - PERIOD NO. 1737

0 0.5 1 1.5 2 2.50

1

2x 10

-3

2*|F

FT

|w o

f y-

acc.

0 0.5 1 1.5 2 2.50

1

2x 10

-3

2*|F

FT

|w o

f z-

acc.

frequency [Hz]

• Client spends approximately $500K per year on

mitigation costs of pipeline spans for a single

pipeline

• Current model suggests mitigation measures

must be taken on any unsupported span over

20 ft.

• Monitoring chosen to measure VIV response

and current data to calibrate model.

• Little to no evidence of VIV was found to be

present in either the cross-flow or in-line

direction increasing acceptable span length to

35 ft.

Typical VIV Spectrum

Monitored Data

www.pulse-monitoring.com 6

Typical system layout


Current Meter

ROV Deployable Motion

Logger


Estimated Cost Savings


$120,000

Campaign

Costs

$130,000

1st Year Savings

$250,000

2nd Year Savings

$0 $100,000 $200,000 $300,000 $400,000 $500,000

No Monitoring(1 Year)

With Monitoring(1 Year)

$130,000

$500,000

Cost SavingsCampaign

Costs

Mitigation

Costs

Mitigation

Costs

$250,000 $120,000


Pipeline Free Span MonitoringSummary

• Pipeline free spans can experience

accelerated fatigue due to VIV

• Pipeline operators are spending

millions of dollars mitigating span

issues with sand bags, grouting, etc.

• Span monitoring provides data to

reduce conservatism in design and

reduce mitigation costs by extending

critical span length and reducing risk

www.pulse-monitoring.com 9

Pulse Structural Monitoring

Paul Chittenden

M: +1 713 422 2674

[email protected]



Thank you!

http://www.pulse-monitoring.com/

pipeline span monitoring & flow rate optimization

Engineering