Slide 613 April 2023

Corrosion Assessment – Failure Criterion

}{ Stress, Flow

Stress Failure Predicted

SMYSf

failure

},,{ Factor, Folias

}{ Area, Original

Metal Missing of Area

tDLfM

tLfA

A

11

1

MA

AA

A

o

oFailure

Slide 713 April 2023

Predicted Failure Stress

100% SMYS

MOP

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Depth of Metal Loss, % Wall Thickness

Pre

dic

ted

Fa

ilure

Str

ess

, ps

i

Length = 0 inches

Length = 1 inches

Length = 2 inches

Length = 4 inches

Length = 8 inches

Length = 12 inches

Length = 24 inches

Length = 36 inches

24-inch diameter x 0.250-inch wall thickness, API 5L X52 (modified B31G)

Slide 1013 April 2023

Probability of Exceedance (POE)

Slide 1113 April 2023

Regression - Leak

y = 0.6211x + 0.141

R2 = 0.3955

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

100.0%

0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0%

ILI reported Depth (%WT)

Fie

ld M

easu

red

Dep

th (

%W

T)

Slide 1213 April 2023

SRF Comparison

y = 0.5049x + 0.4304

R2 = 0.297

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

SRF-ILI

SR

F-F

ield

Regression - Failure

Rupture (Depths and Lengths)

11

1

MA

AA

A

o

oFailure

SRF(Stress Reduction Factor)`

Slide 1413 April 2023

Cumulative POE

)1(11

i

n

iCumulative POEPOE

Slide 1613 April 2023

1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1.0E+09

1.0E+10

1.0E+11

1.0E+12

1.0E+13

1.0E+14

1.0E+15

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

YearP

rob

abili

ty o

f E

xcee

dan

ce (

PO

E)

No excavations after

Excavations after survey

Increasing number of excavations done over time

Slide 1713 April 2023