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1Vallourec & Mannesmann Tubes
OCTG Division
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
2Vallourec & Mannesmann Tubes
OCTG Division
● 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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OCTG Division
● 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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OCTG Division
● 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)
5Vallourec & Mannesmann Tubes
OCTG Division
DCB results – 3% H2S
0
1
2
3
4
KISSC (ksi.in1/2)
Nu
mb
er
d = 28 / 0,71
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OCTG Division
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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OCTG Division
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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OCTG Division
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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OCTG Division
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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OCTG Division
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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OCTG Division
Thanks
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OCTG Division
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
13Vallourec & Mannesmann Tubes
OCTG Division
● Material: KISSC vs KIapplied with all data tested under 100% H2S
Klim ~ 21,1 MPa.√m (19,2 ksi.√in)
Annex