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Efficient Ways of Increasing In-Line Inspection Reliability. 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
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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
Main Disadvantages of MFL method • High magnetization level • Estimation of defect severity level strongly depends on pipeline defect identification
High magnetization level • Active electronic bypass (speed control) device • V = 0 • V = 4 m/s
High magnetization level • Advantages of ordinary SNG ILI tools
High magnetization level • Alternative magnetization scheme Very high friction
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
Comparison of ILI technologies detection of cracks with superimposed general corrosion
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%
EMAT in-line inspection Pipe Coating Waves EMA system
Artificial crack signals Hole Crack Hole Crack TFI Length 41 mm Depth 4 mm Width 0.01 mm EМАТ
EMAT in-line inspection TFI EМАТ
EMAT in-line inspection challenge • Cracks with nearly zero opening • Detection • Identification • Sizing • Thick pipe wall corrosion damage • Detection • Identification • Sizing