Operational limits for casing and drill pipe steels in H{sub 2}S containing environments

Book · Fri Aug 01 04:00:00 EDT 1997

OSTI ID:504760

Edwards, J D ^[1]; Espelid, B ^[2]

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1. Det Norske Veritas, Hoevik (Norway)
2. Det Norske Veritas, Bergen (Norway)

The sulfide stress cracking (SSC) resistance of 32 casing and drill pipe materials corresponding to API 5D/5CT grades C-95 to S-135 has been evaluated using NACE TM0177 tensile testing. The standard method has been extended to include a range of temperatures from ambient to 107 C, and H{sub 2}S contents in the gas phase in the range 100 to 0.1 mol. By defining an acceptable material as one that can bear a minimum load corresponding to 80% specified minimum yield strength for 720 hours in the given combination of H{sub 2}S content and temperature, the results so derived have been used as the basis for defining operational limits for each material grade. In most cases these limits extend the useful application of the casing materials compared to NACE MR0175, particularly in marginally sour environments. The results showed that materials of the same API grade sourced from different manufacturers had variable performance, particularly when the aggressivity of the environment was increased. It was also found that the SSC resistance of specially modified C-steels that are marketed as sulfide resistant was poorer than anticipated. These inconsistencies emphasize that some kind of qualification testing and quality control is necessary when selecting such materials. A thorough analysis of the mechanical properties, chemical composition, and metallography of the materials facilitated correlation with the SSC results and hence derivation of guidelines for procurement/specification of materials for use in H{sub 2}S containing environments. These are intended as a practical guide for the selection of casing and drill pipe materials for H{sub 2}S-service in formation waters of pH 3.5 or higher.

• OSTI ID: 504760
• Report Number(s): CONF-970332--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
36 MATERIALS SCIENCE
CARBON STEELS
CORROSION RESISTANCE
CORROSIVE EFFECTS
CRACK PROPAGATION
DRILL PIPES
EXPERIMENTAL DATA
HYDROGEN SULFIDES
LIMITING VALUES
LOW ALLOY STEELS
MECHANICAL TESTS
SPECIFICATIONS
STRESS CORROSION
SULFIDATION
WELL CASINGS