ilia view: in-line inspection state-of-the-art for scc presented by: scott thetford manager-...

ILIA View:In-Line Inspection State-of-the-Art

For SCC

Presented by:Scott Thetford

Manager- Government RelationsGE-PII

OPS Workshop on SCCDecember 2, 2003Houston, Texas

Introduction

• Current ILI Technologies applied to SCC Detection

• Next Generation SCC ILI

Current Applied ILI Technologies

• Magnetic Flux Leakage– Axial– Transverse

• Ultrasonic– Shear wave

• Electromagnetic Acoustic Transducer

Magnetic Flux Leakage

Goal: Detection of gross SCC• MFL Coupled with other data sources

– Axial + Transverse– Axial + Elastic Wave (Wheel Coupled Shear

Wave)– MFL + DA

• While results have been good more effort needs to be applied to understand limitations.

Feature seen by Transverse Field Inspection

Feature Seen by Axial is Small to non-existent

Magnetic Flux Leakage

Axial Field + Transverse Field = Gross SCC Screening ApplicationAxial Field + Transverse Field = Gross SCC Screening Application

• Different tools for liquid and gas pipelines• Liquid Coupled UltraSonic Shear Wave – for

liquid lines (Natural Gas lines with batching)• Emat – for gas pipelines• Liquid filled wheel probes – for gas or liquid• High resolution tools for

– detection and – sizing of smallest cracks of all types

• Ideal for monitoring crack growth• Detection of hairline cracks

Ultrasonic Technologies

UltraSonic Shear Wave Crack DetectionOutline of Detection Capabilities:• Minimum crack length of 30 mm • Length accuracy +/- 5 mm• Minimum crack depth of 1 mm (2mm for mid-wall cracks)• Longitudinal orientation within +/- 10o

• Depth categorized as – < 12.5%– 12.5% to 25%– 25% to 40%– > 40% of wall thickness

• Probability of Detection > 90%

UltraSonic Shear Wave Crack Tools

Tool size range• Until 2001: 24”+ diameter• 2001 16” – 20”• 2003 10” – 14”• Challenge: space restriction in small diameters

16”-20” Tool in Service

Launch into tool trap

Sensor Carrier Array

Stress Corrosion Cracking

• Detected by Ultrasonic Crack Detection

• Excavation comparison

• Excellent prediction in size and shape

Single Crack Feature

SCC Field

• SCC featureclose-up

• Excavation vs. tool prediction

10” to 14” Now in Service

EMAT Goals

• Detection of sub-critical SCC• Determination of length and depth of axial

cracks• Operate without a liquid couplant • Cost-effective inspection• Discriminate int./ext. & injurious/non-injurious• Full wall coverage • Robust and reliable design • Similar detection targets to UltraSonic Shear

Wave Crack Detection Tools.

Wave types Emat

UltraSonic Shear Wave

Emat

SCC Detection- Live Line

Real feature: SCC Emat

length 300 mm, depth 4.5 mm

Next Generation SCC ILI

• Automated Feature Analysis.• Increased Feature Database = Increased

accuracy of failure models.• Cracking and Corrosion Combination

Tools.• Other Sensor Developments

– Gas coupled ultrasonic– Eddy current

ILI Association – founded April 2002

www.ILIAssociation.org

Thank you.

www.ILIAssociation.org