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DCB performances of C125 material in various environments

API Resource Group on Sour Service ProductsWI 2318a – Sour Service DCB TestingWestminster, Colorado June 12, 2012

Frédéric LEGAYCédric LINNE

VALLOUREC MANNESMANN OIL & GAS DIVISION

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● Material: C125 material Yield Strength: [125ksi – 135ksi] Hardness: < 34HRC NACE A suitable for Mild Sour conditions (3% H2S, pH 3.5, 85% SMYS)

Various sizes Casing with OD [7’’ – 14’’] + associated CS

● Environments: Full NACE environment: 100% H2S / sol. A / pH 2.7

Fit For Purpose environments: 5% NaCl – 0.4% CH3COONa

pH (HCl adjustment): 3.5 H2S level: 3% / 7% / 10%

Introduction

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● Testing protocole: According testing matrix shown below Specimens = Chevron design No fatigue pre-cracking Temperature = 75 ± 3°F (24 ± 1.7°C) Duration = 14 days

Tests conditions

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● Tested specimens

● KISSC (ksi.√in):

DCB results

More data in full NACE environmentHigher scattering in ffp environments

Few invalid due to non propagation (most = pinning / non plannar)

Lot of dry cracks (mostly in ffp but also in full NACE)

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DCB results – 3% H2S

0

1

2

3

4

KISSC (ksi.in1/2)

Nu

mb

er

d = 28 / 0,71

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DCB results – 7% H2S

0

2

4

6

8

10

12

KISSC (ksi.in1/2)

Nu

mb

er

d = 28 / 0,71

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DCB results – 10% H2S

0

1

2

3

4

5

6

KISSC (ksi.in1/2)

Nu

mb

er

d = 28 / 0,71 d = 20 / 0,51

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0

5

10

15

20

25

30

35

40

KISSC (ksi.in1/2)

Nu

mb

er

d = 28 / 0,71 d = 20 / 0,51 d = 15 / 0,38

DCB results – 100% H2S

More used environmentKlim measured

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KISSC vs KIapplied

● Material: Single references

17A - Klim = 20,6 MPa.√m (18,7 ksi.√in)

13B - Klim = 20,0 MPa.√m (18,2 ksi.√in)

17A 13B

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Conclusions

● All results in line with compliance analysis

● Fit For Purpose environments lead to scattered values Need to use same environment than for NACE A ?

● No need of precracking using Chevron design

● Lot of dry cracks observed (all environments)

● In Full NACE environment: “low” KISSC ~ 18-25 ksi.√in when using standard Q125 arm displacement

Klim ~ 19 ksi.√in

● More data needed to determine Klim in other conditions

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Thanks

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Annex

● Dry cracks in ffp conditions: Taken into account in crack

length to be in line with compliance analysis

● Standard crack in full NA in full NACE conditions

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● Material: KISSC vs KIapplied with all data tested under 100% H2S

Klim ~ 21,1 MPa.√m (19,2 ksi.√in)

Annex