IN-LINE INSPECTION OF 42 GAS PIPELINE USING AN …indonesiangassociety.com/wp-content/uploads/2016/06/TS-4-Michael... · According to API 1163 this corresponds to a confidence of

IN-LINE INSPECTION OF 42”

GAS PIPELINE USING AN

ADVANCED TOOL COMBINING

THREE TECHNIQUES –

3TM

Speaker: Dr. Michael Haas

Date: June 2014

18.06.2014 Copyright © 2013 | NDT Global 1

3TM TOOL – 40/42‘‘


3TM PRINCIPLE: EMAT + COMPLEMENTARY SENSORS


With the EMAT sensor we measure the local remaining wall thickness in

gas pipelines the same way classical UT ILI tools do in liquid pipelines! Depth

sizing accuracy is ± 0.5mm, compared to ± 10% for MFL!

DISTINGUISHING EXTERNAL AND INTERNAL DEFECTS BY USING EMAT, EC, MFL.


External Internal

3TM: MEASURING THE LOCAL WALL THICKNESS


Seamless pipe with varying local wall thickness

MFL: 40% depth

Nominal wall thickness used by MFL: 20mm -> remaining wall thickness 12mm

Local wall thickness 22mm -> remaining wall thickness 13.2mm

Local wall thickness 18mm -> remaining wall thickness 10.8mm

Nominal WT local WT

With the EMAT sensor we measure the local remaining wall thickness in

gas pipelines the same way classical UT ILI tools do in liquid pipelines! Depth

sizing accuracy is ± 0.5mm, compared to ± 10% for MFL!

IN-LINE INSPECTION OF 42’’ GAS PIPELINE


Inspection Targets & Summary of 3TM ILI Findings

Inspection necessary to identify significant laminations and inclusions,

and internal and external corrosion in the pipeline. Coating: Coal Tar

Enamel, cathodic protection used.

3TM ILI findings:

External and internal corrosion, laminations, inclusions and dents were

found on the line

•25 laminations and 35 inclusions

•Laminations and inclusions are parallel to the wall

•Depth of external corrosion ranges from 8% to 17%

•Depth of internal corrosion ranges from 8% to 16%

•17 dents were found

3TM ILI FINDINGS


External and internal corrosion

EMAT C-Scan

EC C-Scan

EMAT B-Scan

EC C-Scan

MFL C-Scan

MFL & EC Profile

Deepest internal corrosion, depth 2.0 mm

Deepest external corrosion, depth 2.1mm

0.3m

0.15m

3TM ILI FINDINGS


Laminations and a dent

Laminations running parallel to the surface

EMAT C-Scan

EMAT B-Scan

EMAT C-Scan

EC C-Scan

Dent next to a girth weld

0.2m

1m

VERIFICATION OF 3TM ILI FINDINGS


Feature Type Field Depth (mm) 3TM Depth (mm) Field Length (mm) 3TM Length (mm)

external metal

loss 1.7 2.1 15 10

internal metal loss 1.4 2.0 80 69

Field Width (mm) 3TM Width (mm)

lamination 25 17 80 69

laminations

& inclusions 150 120 460 420

intermittent

laminar inclusions 160 n.a. 650 n.a.

laminar inclusions 170/ 159 830 722

intermittent

lamination 115 101 365 346

intermittent

lamination 100 101 300 275

laminations &

inclusion 155 142 880 848


laminations &

inclusion 65 59 360 352


SUMMARY OF IN-LINE INSPECTION OF 42” GAS PIPELINE


•The pipeline had laminations which needed to be confirmed for any

growth.

•UT-ILI is the only technique that can be used.

•However traditional UT-ILI requires water batch and pipeline

shutdown, which was not possible.

•3TM tool found to be the most suitable option.

•The verification using phased-array proved that the 3TM tool detected

the anomalies including laminations as per specification.

•This inspection activity was successful not only for the use of newly

developed inspection technique but also for the operation of pipeline.

PULL TEST RESULTS


River Bottom Profile 3TM EMAT vs. Laser

Data: Box ID:229

Length [mm] 1116

Width [mm] 1021

Depth [mm] 1.5 +/- 0.5

RWT [mm] 8.0 +/- 0.5

RSTRENG (effective area)

Failure

pressure

[kPa]

RPR

(Eff.Area,

1.25MAOP)

eff. depth

[mm]

eff. length

[mm]

start eff.

length

[mm]

8510 1.056 0.95 475 275

B31G

Failure

pressure

[kPa]

RPR

(B31G,

1.25MAOP)

7470 0.927

mod. B31G

Failure

pressure

[kPa]

RPR

(mod.B31G,

1.25MAOP)

8210 1.018

Failure pressure calculation: Grade X65 (SMYS 448 MPa); MAOP = 6450 kPa; WT = 9.5 mm

PULL TEST RESULTS


Integrity Assessment 3TM EMAT vs. Laser Scan

Mean relative difference is 3.1% only!

Failure Pressure 3TM always ≤ Failure Pressure Laser Scan

FURTHER VERIFIED 3TM ILI FINDINGS


External corrosion: maximum depth from 3TM: 2.6mm, field verification: 2.5mm;

local WT: 14.3mm

0.5m

UNITY PLOT: COMPARING 3TM DEPTH MEASUREMENTS WITH LASER SCANS AND FIELD VERIFICATIONS


19 out of 22 3TM depth measurements are within ± 0.5 mm of the verification

depths, i.e. within specs. According to API 1163 this corresponds to a confidence of

more than 90%.

NDT Global GmbH & Co. KG

Friedrich-List-Str. 1

76297 Stutensee, Germany

www.ndt-global.com

THANK YOU!

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IN-LINE INSPECTION OF 42 GAS PIPELINE USING AN …indonesiangassociety.com/wp-content/uploads/2016/06/TS-4-Michael... · According to API 1163 this corresponds to a confidence of