Pipeline Opera Operations tions and Int Integrity egrity Management Module 4 Inspection Methods
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Outline
Where are we? we?
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Module Outline •
In this Module we will look at Right of way Inspection, the use of ILI tools, hydrotesting and direct assessment methods to determine the condition of the pipe and its surroundings.
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Planning and Conducting Pressure Tests •
Minimum pressure test requirements are given in the regulations, as well as in industry standards and recommended practices. International Standard –
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United States – – –
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ASME B31.4 Section 437 “Testing” (liquid) 49 CFR 195 Subpart E (liquid) ASME B31.8 Section 841.31 “Testing after Construction” (gas) 49 CFR 192 Subpart J (gas)
Canada –
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API 1110 “Pressure Testing of Liquid Petroleum Pipelines”
CSA Z662-07 Section 8 Alan Murray 2017
Test Procedures - Pressure-Volume Charts •
Above the maximum operating pressure and approaching the target pressure –
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Slow and controlled pressurization (e.g., ~10 psi / minute)
Nonlinearities indicate possible yielding of some pipe joints due to: –
Thinner wall
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Lower yield
Target Pressure
Operating
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Nominal Yield
Test Procedures - Acceptance Criteria •
Leak tightness –
49 CFR 195.300 requires a four hour hold
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No unaccounted for pressure drop
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Pressure variations due temperature can cause small increases and decreases in pressure
Double stroke rule –
The pressure test should be stopped when it take twice the number of strokes of the pump to attain the same pressure increase
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Pressure v Volume Plot PRESSURE SHOULD NOT BE INCREASED BEYOND THIS POINT E R U S S E R P
OFFSET LINE P vs. V PLOT
0.2% TEST SECTION VOLUME
VOLUME
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Plotting the Test
Stabilization
Strength Test
Leak Test
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Disposal of Test Medium
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Dewater site during discharge
Energy diffuser during discharge
Two cell dewater site post discharge
Two cell dewater 70 site during discharge
Hydrotest Planning - Test Pressure •
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Test pressures are defined by the minimum pressure needed. The minimum pressures occur at the highest points. Below that point, the pipe will see a higher pressure: –
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For fresh water, a 100-foot change in elevation corresponds to a 43.3 psi pressure difference. For salt water, a 100-foot change corresponds to a 44.5 psi difference.
Testing in segments allows you to manage the difference between the minimum pressure in the line (the highest spot) and the aximum pressure in the line (the lowest spot).
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Hydro-Test Ruptures
Defects that Remain in Pipe
125 % MOP Defects removed Hydro-test
100 % MOP Normal Operating
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2: Hydrotest Planning - Test Pressure
Note: Hydrotests do not expose short and deep defects. 73
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PIPELINE PROTECTION: Above Ground Inspections
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Close Interval Potential Survey This survey measures the pipe to soil potentials along the pipeline, to check the CP system ‘CIPS’ will detect high or low potentials that may indicate problems such as interference from other structures, coating damage, etc.. Direct Current Voltage Gradient ‘DCVG’ detects coating defects in buried pipelines. It examines the voltage gradients in the soil from the CP system, and can locate and estimate a relative size of the coating defect. We check for external corrosion using various ‘above ground survey’ methods: Electromagnetic Methods 74 (PCM) can Pearson, ACVG, Pipeline Current Mapping locate coating defects. •
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ACVG Technique
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AC current on pipe and ground probes in contact with soil above the line, and off the line away from the electromagnetic field.
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ACVG Technique •
When a coating fault is present, the AC current will follow the path of least resistance between the two ground probes rather than the higher resistance soil.
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ACVG Technique •
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Higher frequency AC current will travel through higher resistance soil than DC current = more sensitive than DCVG. Cannot determine corrosion potential, or current direction - stray current going on the pipe can be misinterpreted as current off the pipe. 78
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Electromagnetic Survey Theory •
induction of an alternating current onto the pipeline, which produces a corresponding electromagnetic field around the pipeline
Electric Current flowing in a conductor creates a magnetic field that radiates out from the center of the conductor in concentric circles.
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Attenuation on Good Coating •
The attenuation of the resulting electromagnetic field along the length of a pipeline is consistent on pipelines with continuous homogenous coating AC Current
Current
Electromagnetic Field
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Electromagnetic Survey Theory •
Create, Control, Detect and Record the electromagnetic field from above ground.
Current
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Inspection Bend Locator Pigs record the severity of bends and the position along the pipeline. It is important to know the minimum bend radius that the Bend Locator pig can negotiate as well as the minimum local bore restriction capability.
Photo courtesy of TD Williamson
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Electromagnetic Survey Theory •
Lengths of the pipeline with coating faults will allow larger amounts of the electromagnetic field to return to ground, causing increased attenuations in the field AC Current
Current
Electromagnetic Field
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Range of tool types & uses Classification
Specific Threat
Surface Corrosion
General External Corrosion
Axial External Corrosion
Internal Corrosion
Internal & Material Anomalies plus Features
SCC
Mfg Related Defects
Hard Spots
Surface Breaking Axial Cracking
Surface Breaking Circumferential Cracking
Pipe Long Seam Pipe Girth Weld Wrinkle Bends
Pipe Deformation
Dents, Wrinkles, Buckels, & Ripples
Third Party Damage
Scratch/ Gouges Earth Movement
High Resolution Axial MFL Transverse MFL
EMAT Geometry Tool Disks to +/- > 1% d/D Deformation Tool to +/- 0.5% d/D High Resolution Direct Assessment
Pressure Test
Spike Hydrostatic Test
Inertial Navigation Direct Examination (includes NDE for threat) Red
Not appropriate or never used
Y el lo w
H as ap pl ic ab il it y, p ro vi de s a n a nc il la ry b en ef it or sp ec if ic re st ri ct io ns ne ed to be co ns id er ed
Green
Is appropriate Notes
This matrix is to help those less familiar with the range of integrity assessment technologies, ILI tools, and their capabilities. Technology improvements may allow color changes in the future. Direct Assessment requires following all the NACE Standard requirements of EC, IC, or SCC. Axial & Circumferential Cracking represents surface breaking and partially open cracks unlike tight fatigue.
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INGAA IMCI 23 2b
Sample System
Current
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PIPELINE PROTECTION: Internal Corrosion Pipeline protection starts with a good design and construction. •
INTERNAL CORROSION – We can include a ‘corrosion allowance’ (increase thickness of line pipe) to accommodate in-service, predictable, corrosion. •
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But we prefer to prevent internal corrosion by: •
Treating the product prior to entry into the line, and checking quality;
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Cleaning the line;
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Mixing chemicals to inhibit any corrosion;
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Lining with a corrosion resistance alloy.
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Internal corrosion occurring in water phase
Types of Smart Pigs •
Geometry - Caliper, Caliper, Deformation, Deformation, Gauge –
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Inertial Navigation (Mapping) –
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3D mapping, route surveying, bend and strain measurements
Metal Loss (MFL & UT) UT = EMAT –
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Detecting changes in ovality (dents, deformations)
Detection and sizing of metal loss corrosion, pits, etc.)
Crack Detection (UT & MFL) –
Detection and sizing siz ing of cracks and crack-like defects defects
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Geometr Geometry y Tools Tools •
Pipe sizing and deformation detection
• Detects girth welds, wall thickness changes and installations (e.g. valves, tees, etc.) –
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Acceptance of new pipelines Mechanical and 3rd party damage Passage Passage of other ILI tools
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Enduro27
Inertial Inertial Guidance Guidance Tools •
Inertial navigation navigation - gyroscopes gyroscopes and accelerometers –
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Measures angular and velocity changes in X, Y and Z coordinates coordinates Determine 3-D position of the pipeline.
Verifying and creating pipe books • –
Determining pipeline movement
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Measuring bends
Overlaid on geographical maps provide exact “as is” view of pipeline
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Metal Loss Tools - MFL •
Field lines increase due to reduced cross sectional area
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MFL •
Axial Direction Magnetize in the axial direction
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Girth or Hoop Direction Referred to as Transverse or Circumferential
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Pure Tech & GE
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Metal Loss - UT •
Normal Beam
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GE 32
UT Tools •
Direct measurement & Wide range of detectable features
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Internal / external + mid-wall defect discrimination
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Reliable sizing
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Supports advanced MAOP assessment • No upper wall thickness limitation • Straight forward data analysis • Operates only in liquids (liquid slug in a gas pipeline) • EMATs are contactless UT technology in gas
• Angle Beam (Shear Wave) for cracks, SCC, seam, girth weld
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Pipeline Operator’s Forum •
Ranges
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Inspection Objectives •
Macro View in valve section (NEW) –
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Records comprehensive, complete, & validated
Micro View of Pipeline Surface –
Detection of Defects •
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Type - POD Geometries – Volumetric, Planar
Sizing of defects •
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Depth width & Length = 3 Cylindrical Profile Accuracy of POI
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Detection Details - 1 •
Pigs can generally find what you expect –
Need to use the right tools for the defect
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Depends on the defect size (smaller = harder)
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Depends on tool performance (API 1163)
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Depends on pipe condition •
Debris & deposits
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Material variations
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Proximity to features such as “T”s & valves
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Unity Plot indicates Performance
Statistics help
Feedback to ILI Vendor Critical
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Detection Details - 2 • Will pigs Detect as false calls? •
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Sometimes indicates defects where there are none
Will the pig detect defects it was not designed to find? –
Probability of detection maybe low
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Use as maintenance information
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Do not use to project safety & reliability
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Consider High Accuracy when •
Off shore or when excavation $$$$
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Reliability high – not looped
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Environmentally sensitive - penalties high
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Safety in High Population Densities
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Expect many small defects and only a few need repair
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Consider Low Accuracy when •
Long pipe runs in remote areas
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Small number of defects expected
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No previous ILI inspections
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Leak & accident free operating history
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Old line / expertise right sized
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Cathodic Protection Performance unreliable
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Plan to dig all the indications Al
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GIS Automated Integrity Sheet
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GIS Automated Integrity Sheet – Close-up
Church Complex
Anomaly
Ball Field
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Aerial of Anomaly Location
Church Complex
Anomaly
Ball Field
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Anomaly Investigation Result
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Two opinions always better than one •
Ask
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Rosen46
INGAA 2011 survey; 146,000 miles
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Can’t use normal free swimming tools
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Can’t easily get into and out of the pipeline –
Too congested, unsafe access points,
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Pig will get stuck at internal constrictions
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Can’t reduce flow or take line out of service
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Reverse flow needed to drive pig in & back out Too long can’t inspect all
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“Unpiggable
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Simple: unable to be pigged. Better: pipelines with inherent design or current operational
parameters preventing existing ILI technologies from accessing, navigating, or inspecting the pipe segment. Realistic: not pigged because of objections: priority, budgetary, preferences and/or limited understanding.
Clarion Workshop – “unpiggable” as a concept has value PRCI - there is no such thing as “unpiggable” it just takes ingenuity &
money. Alan Murray 2017
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Preplanning is Key •
Thomas Beuker Rosen pointed the way
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Rosen & Clarion50
Think ‘Off the Shelf’ Components
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Rosen & Clarion51
Getting big things in through small spaces
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BJ Lowe & Clarion52
Explorer II RFEC 6”/8” 2 miles
Explorer II MFL 10”/14” 2 miles
Explorer II MFL 30”/36” 2 miles Alan Murray 2017
NYSearch & PipeTel 53
Self Powered ILI •
16” robotic launch
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BJ Lowe & Clarion 54
Might you consider these for access?
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Wall Loss in Perspective •
KAPA? –
Wall &
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Cracks
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Putting it together to plan work •
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ILI firms provide software to help integrate inspections Use API 1163 & contract to have them precondition data to yours
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Rosen ROSOFT Apps
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Why Hydrotest? •
To demonstrate leak tightness.
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To “prove” strength or soundness (integrity).
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To remove detrimental anomalies.
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To mitigate some types of anomalies.
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To meet codes and regulations.
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Potential Hydrotest Problems •
Difficult to find leaks. –
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Numerous leaks/ruptures – –
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Various tracer elements that can be detected above ground can be used Their effectiveness drops as burial depth increases Difficult to find leaks nearby earlier test leaks Running out of tracer elements
Ballooning pipe – –
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Relatively new problem Considered most probably when there are limited numbers of under strong pipe joints
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Pressure Test Basics - 1 •
Test Pressure Determined based on the desired results of the test. Can range from below SMYS to above SMYS. Higher test pressures needed for strength testing. Lower test pressures are more appropriate for leak testing. –
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Test Pressure Hold Time Can range from very short (e.g., 5 seconds), to moderate (e.g., 30 minutes), to long (e.g., 8 hours). Short times are more appropriate for strength testing. Long times sometimes needed for leak testing. –
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Pressure Test Basics - 2 •
Test Medium Typically water, product (liquid), gas, or air are used as the test medium. The amount of “stored energy” can be large regardless of test medium. –
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This is true even when short segments are being tested. Gas or air tests have a much higher “stored energy” when used as the test medium
Detection Methods Leaks – –
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Ruptures – –
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Inability to hold pressure, pressure drop, walking the line, trace element (sniffers), and dyes. Immediate pressure loss.
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Pressure Test Basics •
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Test Pressure –
Determined based on the desired results of the test.
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Can range from below SMYS to above SMYS.
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Higher test pressures needed for strength testing.
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Lower test pressures are more appropriate for leak testing.
Test Pressure Hold Time –
Can range from very short (e.g., 5 seconds), to moderate (e.g., 30 minutes), to long (e.g., 8 hours).
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Short times are more appropriate for strength testing.
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Long times sometimes needed for leak testing.
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Pipe Mill Tests •
Used to “proof test” newly manufactured line pipe. –
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Quick test that minimize the time for ductile crack growth
Included in API pipe specifications since 1928: –
Early tests called for minimum pressures of 40-50% SMYS.
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By 1970, requirements had increased to 60-75% SMYS.
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Later practices and requirements from 85-100% SMYS.
Short hold times (typically 5 to 10 seconds). –
Pipe mill tests demonstrate strength, not necessarily leak tightness.
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Hydrostatic Testing Equipment a) Test Heads and Caps b)Deadweight Testers (Accuracy & Calibration)
a) Pressure and Temperature
Pen Recorder Ground Surface
a) Fill (Centrifugal)Test andSection Squeeze (Reciprocating) Pump
PIPELINE PROTECTION: External Interference •
Pipeline protection starts with a good design and construction.
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External damage – we can protect our lines from third parties by: •
Thicker pipe wall, or deeper cover (but beware of overburden),
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Locating in remote regions,
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Regular patrols or surveys of the line, and clear markings, and good communications with third parties including general public,
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Protective measures such as concrete casings,
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Damage detection equipment.
Images © Penspen Group
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PIPELINE PROTECTION: External Interference •
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We can reduce the number of times our pipeline is damaged by external interference by liaising with our landowners, and excavators, and making them aware of the location of the pipelines and their dangers. We have other methods of preventing or detecting damage/defects in pipelines; for example, a ‘one call’ system:
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PIPELINE SURVEILLANCE •
We have various methods of preventing or detecting damage/defects in pipelines, for example, leak detection, walking the line looking for damage/leaks, and surveillance by aircraft:
7 Images from www.uncc.org, Columbia Gas, USA and Transco, UK
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Right of Way Patrol •
It is important to mark and then patrol your Right of Way to prevent encroachment
Patrol Frequency depends on the Risk posed by the Pipeline Usually every two weeks in open country ,once per week in populated areas. Al
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TNPI Pipeline RoW in Montreal...
Pipeline
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Note warning signs above Centre line of Pipe
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Basics of ILI Tool Design ID/OD Sensors
Odometer Wheels
Battery
Support Wheels or Support Cups 18
Data Storage
Magnets & Bristles
Main Sensors
Magnets & Bristles
Data Processing
Body + Electronics
Tow Coupling Electrical harnessing
Support/ Drive Cup
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Body may have electronics but could be hollow for gas bypass –
Drive Cup
ILI Standards •
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API 1163 - IN-LINE INSPECTION SYSTEMS QUALIFICATION STANDARD (reafirm 2012) –
System qualifications
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Umbrella standard requires the following two
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Requires operators to share dig info with service provider
NACE SP0102 - In-Line Inspection of Pipelines –
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Operations safety and worker qualifications
ASNDT - ILI PQ - Personal Qualification for In-Line Inspection –
Qualification of those that interpret and provide results
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Types of Smart Pigs •
Geometry –
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Electromagnetic - Magnetic Flux Leakage (MFL), Eddy currents, etc. –
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Intelligent pig that characterizes metal loss along the pipeline
Transverse Magnetic Flux Leakage (TFI) –
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Instrumented pig that maps the inside surface of the pipe to identify ovalities, deformations, and restrictions along the pipeline
Intelligent pig that characterizes metal loss and crack-like features along the pipeline
Ultrasonic (UT) –
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Intelligent pig that characterizes remaining wall thickness and crack-like features
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Inspection Caliper & Geopig •
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3D to 1.5 D bend radius 10% minimum bore restriction
Photos courtesy of BJ Inspection Services
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Attenuation on Good Coating
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The rate of decline (Attenuation) in the field will be primarily dependent on the electrical resistivity of the coating and the area of pipe per unit length in contact with the soil. Perfect Coating 6
90 80 70 60 50
) 5 m / B 4 m ( n o 3 i t a u n 2 e t t A 1
0
0
0 0 1
0 0 2
Attenuation (mB/m)
0 0 3
0 0 4
0 0 5
0 0 6
0 0 7
0 0 8
0 0 9
0 0 0 1
40 30 20 10 0
) A m ( t n e r r u C S M R
Distance (m)
Current (mA)
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What does a pigging survey provide •
Pipeline design information –
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Micro scan – defect sizes by tool type –
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Welds, wall thickness changes, Openings at branch connections, Fittings and valves, Cumulative damage assessment
Macro scan – pipe changes, –
Record validations, (MAOP verification?)
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Launch & Receive
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World Pipelines Aug 2012
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Types of Smart Pigs •
Geometry - Caliper, Caliper, Deformation, Deformation, Gauge –
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Inertial Navigation (Mapping) –
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3D mapping, route surveying, bend and strain measurements
Metal Loss (MFL & UT) UT = EMAT –
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Detecting changes in ovality (dents, deformations)
Detection and sizing of metal loss corrosion, pits, etc.)
Crack Detection (UT & MFL) –
Detection and sizing siz ing of cracks and crack-like defects defects
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