efficient ways of increasing in-line inspection reliability

“NPO SPETSNEFTEGAZ”

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

• 6947 stress corrosion cracking zones

were located and sized

Quantitative Statistics on Types of Detected Defects

Cracks Girth weld anomalyDents Anomaly and mill defectPitting General CorrosionCircumferential groove Axial groovePinhole

Main Disadvantages of MFL method

• High magnetization level

• Estimation of defect severity level strongly

depends on pipeline defect identification

High magnetization level

High magnetization level

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

Photo of cracks on corrosion background

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%

“NPO SPETSNEFTEGAZ”

Advantages of EMAT In-Line Inspection

EMAT in-line inspection

Pipe

Coating

EMA system

Waves

Artificial crack signals

EМАТ

TFI

CrackHole

Length 41 mmDepth 4 mmWidth 0.01 mm

Crack

Hole

EMAT in-line inspection

EМАТ

TFI

EMAT in-line inspection experience

EMAT in-line inspection experience

EMAT in-line inspection experience

EMAT in-line inspection challenge

• Cracks with nearly zero opening– Detection– Identification– Sizing

• Thick pipe wall corrosion damage– Detection– Identification– Sizing