Efficient Ways of Increasing In-Line Inspection Reliability

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Efficient Ways of Increasing In-Line Inspection
Reliability
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Statistics of In-Line Inspection of GAZPROM
pipelines during the last 5 years

• Total 77,900 km gas pipelines were inspected in
  GAZPROM JSC
• More than 1.5 million pipeline defects were
  detected
• 6947 stress corrosion cracking zones were located
  and sized

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Quantitative Statistics on Types of Detected
Defects
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Main Disadvantages of MFL method

• High magnetization level
• Estimation of defect severity level strongly
  depends on pipeline defect identification

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High magnetization level
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High magnetization level
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High magnetization level

• Active electronic bypass (speed control) device

V 0
V 4 m/s
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High magnetization level

• Advantages of ordinary SNG ILI tools

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High magnetization level

• Alternative magnetization scheme

Very high friction
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Disadvantages of MFL method

• In-line inspection of pipelines with thick walls
  is limited due to necessity to magnetize full
  pipe wall thickness up to outer pipe wall surface
  
• All new Russian pipelines including Nord-Stream
  pipeline are thick wall pipelines
• Only limited inspection is possible on almost
  all offshore pipelines

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Comparison of ILI technologies detection of
cracks with superimposed general corrosion
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Photo of cracks on corrosion background
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Pipeline defects identification statistics

• Dig verification statistics reveals real
  ILI tool sensitivity
• Latest results of MFL TFI methods usage
• POD of cracks less than 20 p.w.t. deep is 90
• POI of cracks less than 20 p.w.t. deep is 90
• POI of shallow cracks with superimposed tiny
  corrosion is less than 60

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Advantages of EMAT In-Line Inspection
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EMAT in-line inspection
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Artificial crack signals
TFI
Length 41 mm Depth 4 mm Width 0.01 mm
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EMAT in-line inspection
TFI
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EMAT in-line inspection experience
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EMAT in-line inspection experience
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EMAT in-line inspection experience
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EMAT in-line inspection challenge

• Cracks with nearly zero opening
• Detection
• Identification
• Sizing
• Thick pipe wall corrosion damage
• Detection
• Identification
• Sizing