1. Shallow Internal Corrosion Sensor Technology for Heavy Pipe Wall Inspection
ROSEN Technology & Research Center Germany
Dr. Olaf Stawicki
18-Nov-2009

2. Measurement Principle Mechatronic Principle Inspection Tool Design
Contents
Motivation
Measurement Principle
Mechatronic Principle
Inspection Tool Design
Combining SIC with MFL
Test Results
On-Site Example
Summary
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

3. Pipeline Integrity Assessment
Motivation
Risks for Pipeline Integrity and Operation
Manufacturing
Steel Production
Welding (SAW, ERW) …
Operational
Corrosion
Erosion, Fatigue
Ground Movement
Mechanical Damage …
Pipeline Integrity Assessment
Construction
Girth Weld Faults
Poor Pipe Support …
Coating and CP
Poor Surface Preparation
Inadequate Material Storage …
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

4. Heavy Wall Pipelines for Offshore Applications
Motivation
Corrosion plays a crucial role in pipeline integrity … it is a time-dependent deterioration process
Heavy Wall Pipelines for Offshore Applications
Specified maximum corrosion growth rate
Controlled wall thickness reduction during the lifespan
Monitoring Internal Corrosion is inevitable for reliable and save operation!
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

5. Top of Line Corrosion (TLC) or Dewing Corrosion
Motivation
Top of Line Corrosion (TLC) or Dewing Corrosion
… starts as Shallow Internal Corrosion (SIC)
Origin of TLC
Unprocessed wet gas is transported
from an offshore well
Heat exchange between pipeline and
cold surrounding (such as sea water)
Low pH water droplet condensation on the upper
half of the pipeline
Dissolution of aggressive gases in droplets support corrosion
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

6. Motivation Droplet Condensation of Vapor Phase TExt « TGas Water Drain
H2O, CO2, H2S
Organic Acid (HAc)
TExt « TGas
Water Drain
TGas
TExt
Stratified Water Flow
Droplet Size Distribution ~ r -2/3 localized, small-scale corrosion
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

7. TLC Controlling Parameters
Motivation
TLC Controlling Parameters
Partial Pressure of CO2
Partial Pressure of H2S
Water Condensation Rate
Gas Pressure, Velocity, Temperature
Organic Acid (HAc) Concentration
TLC can reveal high growth rates, up to several mm/year
(Singer et al., 2009)
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

8. What kind of inspection technology is required?
Motivation
What kind of inspection technology is required?
Due to feature sizes and high Corrosion Growth Rates (CGRs), an approach is required with …
… High Sensitivity for early detection and excellent feature discrimination
… Accurate Sizing Properties for determining CGRs effectively
Both primarily for Heavy Wall Gas Pipelines
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

9. Measurement Principle
Alternating current triggers Primary Magnetic Field
Magnetic flux change causes Eddy Currents in conductive material, e.g., pipe wall
Eddy Currents generate Secondary Magnetic Field
Secondary Field modifies Primary Field via mutual inductance
Eddy Currents imply change of coil impedance
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

10. Measurement Principle
• In Air ωL R
• Material
• Metal Loss
Lift-Off
Coil Impedance: Z = R + j ωL
R Ohmic Resistance
ω Frequency of driving current
L Inductance of Coil
“In Air”
“Over Material”
“Over Metal Loss”
Lift-Off
Eddy Currents
Eddy Current Distortion
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

11. Measurement Principle
Penetration Depth determined by Skin Effect
Skin Depth δ ~ 1/(ω μσ)1/2
Eddy Current Density decreases with depth.
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

12. Mechatronic Principle
SIC Sensor = Contour Following Touchless Proximity Sensor
(Compensated Deflection)
SIC sensor schematic view
Radius Measurement =
δ Proximity Sensor (Lift-Off) +
β Electronic Angle Sensor
counts
Lift-Off
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

13. Inspection Tool Design
RoCorr·MFL/SIC 24" Combo Tool
MFL
SIC
Two plane sensor system 100% coverage
Available tool sizes 6" – 56"
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

14. Depth Measurement of Metal Loss Features
Combining SIC with MFL
Depth Measurement of Metal Loss Features
MFL relative
SIC absolute
Compensation for Lift-off
Sensitive Pitting Discrimination
Inner Pipe Wall Surface
SIC Regime
Wall Thickness
MFL Regime
Outer Pipe Wall Surface
Detection & Sizing of External Defects
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009 14
Copyright © ROSEN Group Copy prepared for PPSA

15. SIC feature sizing customizes MFL sizing model
Combining SIC with MFL
SIC feature sizing customizes MFL sizing model
Sample pipe with WT = 20 mm
MFL
Detection Regime
Defect Depth [mm]
SIC Probe
Depth Sizing Accuracies
MFL ± 2 mm
SIC ± 0.5 mm
Defect Diameter [mm]
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

16. SIC Scan of Steel Plate with Spherical Pits
Test Results
SIC Scan of Steel Plate with Spherical Pits
Lift-Off 3 mm
Resolution 2 x 2 mm
EDM-made pits
Depth [mm]
y-direction [mm]
x-direction [mm]
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

17. Test Results Aspect Ratio D/t ≥ 3 Surface Diameters Aspect Ratio
P35.x
Aspect Ratio
P30.x
P25.x
P20.x
P15.x 35
Aspect Ratio D/t ≥ 3
Depth t
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

18. SIC Scan of Steel Plate with TLC
Test Results
SIC Scan of Steel Plate with TLC
Depth [mm]
y-direction [mm]
x-direction [mm]
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

19. SIC Scan of Steel Plate with TLC
Test Results
SIC Scan of Steel Plate with TLC
SIC Depth [mm]
Real Depth [mm]
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

20. Test Results 16" Pump Test Line Spiral Weld Dent Simulation
Internal Defects
Flange
Dent
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009 20

21. Test Results 16" Test Joint, WT = 12.6 mm SIC MFL
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

22. Test Results TLC in 16" Test Pipeline AUT CDP SIC
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

23. On-Site Example - World Longest Subsea Run
Requirements - 42" /44" Langeled Pipeline
Inspection Range 1200 km
Gas Speed 8 m/s
Active Speed Control set at 3 m/s
WT Range 3 – 38 mm
Maximum Pressure 220 bar
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

24. On-Site Example - World Longest Subsea Run
CDP 624 MFL Channels
RoGeo·Xt 330 Geometry Channels
SIC 864 Channels
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

25. On-Site Example - World Longest Subsea Run
Run Results
Traveling time hrs
Tool velocity 1.5 – 3.0 m/s
Almost full pipeline length recorded
3.82 km2 of pipe wall inspected ( = 521 football fields)
11,7 measurement points per cm2
450 billion measurement points
374 GB data recorded
… but data evaluation is still in process
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

26. Compared to other measurement technologies:
Summary
Based on Eddy Current Technology, SIC Sensors have been developed for metal loss inspection on inner pipe wall
Compared to other measurement technologies:
SIC: Absolute depth of metal loss features
MFL: Relative depth based on wall thickness
SIC tools have less friction compared to tools with magnet yokes
SIC Inspection is contactless, i.e. no direct coupling to the pipe wall
SIC sensor metal loss depth sizing Typically between 1 mm and 10 mm depth
Copyright © ROSEN Group Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009
Copyright © ROSEN Group Copy prepared for PPSA

27. Thank you for joining this presentation.