Leak Detection eLearning
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Transcript of Leak Detection eLearning
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Pipeline leak detectioneLearning Part 1 of 2
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Title here again in Arial 24 max. one lineAgendaPipeline leak detection
Historical developmentLeak detection system requirementsCauses of leaksLeak detection optionsNon-continuous leak detectionContinuous external leak detectionContinuous internal leak detection
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Title here again in Arial 24 max. one lineAgendaPipeline leak detection
Leak localizationHuman Machine InterfaceAdditional functions in leak detectionTypical applications of leak detection systems
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IntroductionHistorical development
3 | Pipeline leak detection
3000 BC 500 BC 400 BC
Copper pipes for water transport
First transport ofhydrocarbons
Supplying Peking with natural gas
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Factors influencing the construction of pipelines:
y Discovery of crude oily Development of refineriesy Dependency of oil transporty Invention of the automobile
IntroductionHistorical development
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19th century
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IntroductionCurrent situation
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Oil, crude oil, refined products, natural gases, condensate, process gases, water and salt water
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Title Contents of requirement
Leak detection system requirementsOfficial requirements
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TRFL Technical Rules for Pipelines
API 1130 Computational Pipeline Monitoring for Liquids
API 1149 Pipeline variable uncertainties and their effects on leak detection
API 1155 (replaced by API 1130) Performance criteria for leak detection systems
CSA Z662 Oil and gas pipelines
49 CFR 195 Transport of hazardous liquids via pipeline
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Leak detection system requirementsPerformance criteria
8PipePatrol E-RTTM8 | Pipeline leak detection
Label Description
Reliability Avoid false alarms
Reliably detect leaks
Accuracy Accurate localisation of leaks
Robustness Detect failing sensors
Fall-back strategies in the event of sensor failure
Sensitivity Minimum detectable leak rate
Detection time
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FCauses of leaks
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In Out
y Fatigue cracksy Stress corrosiony Hydrogen indexingy Material manufacturing errorsy External influence
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Leak detection options
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Non-continuous Continuous
External systems
Fibre optic cable
Acoustic systems
Sensor hoses
Video monitoring
Internal systems
Pressure point analysis
Mass balance method
Statistical systems
RTTM-based systems
E-RTTM
Inspection by helicopter
Smart pigging
Tracking dogs
Leak detection systems
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Non-continuous leak detectionInspection by helicopter
Leak detection methods:
y Lasery Infrared cameray Leak sniffer
Usage conditions:
y Detecting small gas leaksy Accuracy depends on weather
conditions
y Poor weather conditions make helicopter flight difficult
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Non-continuous leak detectionSmart pigging
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Types of pigging: Cleaning pigs Batching pigs
Smart pigs Magnetic flux leakage method Testing using the principle of ultrasonic
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Non-continuous leak detectionSmart pigging
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Usage conditions:y Detecting existing and potential leaksy Zero or baseline piggingy Pipeline must be piggabley Accuracy of measurement depends on the pig velocity
1 - 5 m/s
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Non-continuous leak detectionTracking dogs
Trained to smell certain odorant
Usage conditions:
y Short pipelines, segmentsy Containment of leak sitesy Certification difficult
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External leak detectionFiber optic cable
Usage conditions:
y Accurate localisation of leaksy Limited length possible
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Laser
0 s
C
y Many reflections requiredy Cable position must be selected
according to the medium
Gas
Liquids
L
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Usage conditions:
Acoustic sensors directly on the pipeline or with steel rods for underground pipelines
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sL
A AA A A A
Large number of sensors for longer pipelines
y Difficult to detect small leaks
0
dB
A
External leak detectionAcoustic systems
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External leak detectionVideo monitoring
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Usage conditions:
y Short distancesy Continuous leak detection may
be possible
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Pump
External leak detectionSensor hoses
Usage conditions:y Monitoring short pipelinesy Small leaks detectabley Cable position must be selected according to the medium
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Gas detector
Pump time
Gasconcentration
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Internal leak detection
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PLTLP0 T0
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Internal leak detectionOverview of the systems
Extended-RTTM
Volume comparisonmethod
Statistical systems RTTM-based
P T P T
Pressure point analysis
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t0
dp/dt
Internal leak detectionPressure point analysis
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In
P
Out
Upper threshold
Lower threshold
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Internal leak detectionMass balance method
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30
25
20
15
10
5
0
30
25
20
15
10
5
0
Difference
Uncompensated mass balance
In/Out
InOut
Out In
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Internal leak detectionStatistical systems
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In Out
LeakNo leak
Alarm
Probability
Statistical variable
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Internal leak detectionRTTM
Conservation of Mass
Real-Time Transient Model
Conservation of Momentum
Conservation of Energy
In Out
L
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PL
Internal leak detectionRTTM
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TLP0 T0
F0 FL
Change in pipe contents
Change in pipe contents
RTTM-compensated mass balance
t
= compensated leak rate
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Internal leak detectionE-RTTM
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PLTLP0 T0
F0
Residual x F0 F0 Residual y FL FL
FL
F0 FL
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Internal leak detectionE-RTTM
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PLTLT0P0
F0 FL
F0 FL
s
Residual x F0 F0 Residual y FL FL
Residuals x and y are used by the system as decision values
Leak signature
x
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Internal leak detectionCapabilities of internal systems
Method Typical min. detectable leak rate
Time to detect leak (liquids)
Time to detect leak (gases)
Detectable types of leak
False alarm frequency
Accuracy of leak localisation
Pressure point analysis
> 5% Short Long Spontaneous leaks
High High with additional pressure sensors, dependent on sampling rateMass balance
method> 1% Long Very long Spontaneous
and creeping leaks
High Average with additional pressure sensors
Statistical methods
> 0.5% Long Very long Spontaneous and creeping leaks
Slight Average with additional pressure sensors
RTTM > 1% Short Short Spontaneous and creeping leaks
Average High
E-RTTM > 0.5% Very short Short Spontaneous and creeping leaks
Slight High
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Leak localizationOverview
Possibility of combining methods
y Improving accuracyy Reducing problems in localizing
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Gradient IntersectionMethod
s
p
Wave PropagationMethod
t
sExtended Wave Propagation
Method
t
s
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Leak localisationGradient Intersection Method
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p
sL0 sLeak
In
P
Out
P
p0
pL
Advantages Localising: spontaneous, creeping leaks Good accuracy with stationary operation Disadvantages Accuracy depends on length of pipeline Pipeline geometry must be taken into consideratio
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Leak localisationWave Propagation Method
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t
sL
sLeak
p0
pL
tLeak
t
0
In
P
Out
P
Advantages Good accuracy
Disadvantages No localizing of creeping or small leaks Fast sampling required
Can be used during operation and pauses
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Leak localisationExtended Wave Propagation Method
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t
sL
sLeak
p0
pL
tLeak0
In
P
Out
P
Good accuracy
P P
p2p3
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HMI (Human Machine Interface)
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HMI (Human Machine Interface)
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Added functions in leak detectionEfficiency analysis
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87% efficiency
100% efficiency
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y Inventory calculationy Operator trainingy Theft detectiony Hydraulic profiles
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Added functions in leak detection
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Added functions in leak detectionBatch tracking
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Batch trackingy Tracking products and
mixing zones
Batch schedulingy Scheduling arrival times
and capacities
y Scheduling of deliveryy Reducing waste
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Typical applications
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Typical applicationsFPSO to refinery
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Long pipelines with large diameters Substation measurements impossible
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Typical applicationsOil field to refinery
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Long pipelines with large diameters Changes in viscosity and density Elevation and temperature differences
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Typical applicationsOffshore drilling rig to refinery
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Changes in viscosity and density Substation measurements impossible Large diameter
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Typical applicationsRefinery to tank farms
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Several products with various densities
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Typical applicationsGas field to refinery
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Long pipelines with large diameters
Elevation and temperature differences
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Typical applicationsChemical plant to chemical plant
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Heavily transient operation of pipelines
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Typical applicationsSea to city
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Long pipelines with large diameters
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Choosing the right leak detection system
No leak detection system isthe perfect choice for every application
Selection of the system depends on:
y Desired resultsy Costsy Installation conditions
Individual adaptation leads to optimal performance
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What requirements are placed on the application?
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Title here again in Arial 24 max. one lineSummaryPipeline leak detection
1. Historical development2. Leak detection system requirements3. Causes of leaks4. Leak detection options5. Non-continuous leak detection6. Continuous external leak detection7. Continuous internal leak detection
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Title here again in Arial 24 max. one lineSummaryPipeline leak detection
8. Leak localization9. Human Machine Interface10. Additional functions in leak detection11. Typical applications of leak detection systems
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