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

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009 14 Copyright © ROSEN Group 2009 - Copy prepared for PPSA

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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

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

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

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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

On-Site Example - World Longest Subsea Run Run Results Traveling time 127.3 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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009

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 2009 - Copy prepared for PPSA SIC Sensor Technology | O. Stawicki | 18-Nov-2009 Copyright © ROSEN Group 2009 - Copy prepared for PPSA

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