Sulfide stress cracking resistance of superduplex stainless steels in oil and gas field simulated environments
- Centro Sviluppo Materiali S.p.A., Rome (Italy)
The need to improve stress corrosion cracking resistance in H{sub 2}S/CO{sub 2}/Cl{sup {minus}}, at reasonably low prices and good mechanical properties, has led in the last decade to develop a plethora of superduplex stainless steels for sour oilfield environments application. The outstanding performance of superduplex stainless steels to SSC corrosion is diminished with the increase of chloride concentration and H{sub 2}S partial pressure. In this work the performance of superduplex steel in very harsh oilfield simulated environments (H{sub 2}S up to 20 psi (155 kPa), NaCl 25% and 80 C) were verified, Experimental work was carried out on two grades of superduplex steel seamless tubes, UNS S32760 (80ksi, 560 MPa), as the most commonly used, and UNS S39277, characterized by high strength in the annealed state (90 ksi, 630 MPa). The resistance to sulfide stress cracking (SSC) of duplex and superduplex stainless steels was evaluated in H{sub 2}S/CO{sub 2}/Cl{sup {minus}} bottom hole simulated environments. SSC threshold was determined by means of C-ring (constant strain) testing method. The results were utilized to draw engineering diagrams of superduplex UNS S39277 and UNS S32760. Duplex 22%Cr steel was considered as reference material. SSC resistance of duplex steel was strictly correlated to the acidity of the solution. Critical H{sub 2}S partial pressure in high chloride environments with addition of a buffering agent such as NaHCO{sub 3} is shifted towards higher values. Superduplex steel represents a suitable candidate for the use in the deep high pressure wells with H{sub 2}S partial pressure up to 5 psi (35kPa) and 20% NaCl.
- OSTI ID:
- 351734
- Report Number(s):
- CONF-980316-; TRN: IM9927%%259
- Resource Relation:
- Conference: Corrosion `98, San Diego, CA (United States), 22-27 Mar 1998; Other Information: PBD: 1998; Related Information: Is Part Of Corrosion `98: 53. annual conference and exposition, proceedings; PB: [6600] p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stress corrosion cracking of duplex stainless steel weldments in sour conditions
The corrosion of duplex stainless steels in sour service