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VALLOUREC MANNESMANN OIL & GAS DIVISION. DCB performances of C125 material in various environments API Resource Group on Sour Service Products WI 2318a – Sour Service DCB Testing Westminster, Colorado June 12, 2012 Frédéric LEGAY Cédric LINNE. Introduction. Material: C125 material
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VALLOUREC MANNESMANN OIL & GAS DIVISION DCB performances of C125 material in various environmentsAPI Resource Group on Sour Service ProductsWI 2318a – Sour Service DCB TestingWestminster, Colorado June 12, 2012Frédéric LEGAYCédric LINNE
Introduction • 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%
Tests conditions • 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
DCB results • Tested specimens • KISSC (ksi.√in): More data in full NACE environment Higher 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)
DCB results – 100% H2S More used environment Klim measured
KISSC vs KIapplied • Material: • Single references 17A 13B 17A - Klim = 20,6 MPa.√m (18,7 ksi.√in) 13B - Klim = 20,0 MPa.√m (18,2 ksi.√in)
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
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
Annex • Material: • KISSC vs KIapplied with all data tested under 100% H2S Klim ~ 21,1 MPa.√m (19,2 ksi.√in)