Trials of flexible pipe in sour service reveal degradation

Journal Article · Mon Nov 04 04:00:00 EST 1996 · Oil and Gas Journal

OSTI ID:392625

Al-Maslamani, M J ^[1]

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1. Qatar General Petroleum Corp., Doha (Qatar)

Field trials on flexible pipe offshore Qatar have shown that, under sour conditions, the layered, composite material can suffer severe degradation leading to failure. The failure demonstrates the significant effects of stress level, environmental aggressiveness, and localized hard zones in promoting sulfide stress cracking. Permeability of the sour gas through the composite layer of the flexible pipe resulted in varying degrees of sulfide attack and hydrogen embrittlement, depending on the susceptibility of the multilayered material. In the trials, the material was used as a gas-lift line in a sour-oil field in the Arabian Gulf. Flexible pipes have been used successfully for transporting methanol, benzene, and gas condensates in wet sweet environments at temperatures of up to 80 C. Little or no information, however, has been available as to its corrosion resistance in sour-service wells containing 6% CO{sub 2} with 3% H{sub 2}S partial pressures and at moderate temperatures. The paper discusses an underwater survey to evaluate the damage, visual inspection, mechanical tests, metallographic exam, and trial results.

• OSTI ID: 392625
• Journal Information: Oil and Gas Journal, Journal Name: Oil and Gas Journal Journal Issue: 45 Vol. 94; ISSN OIGJAV; ISSN 0030-1388
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
42 ENGINEERING
CARBON DIOXIDE
COMPOSITE MATERIALS
CORROSIVE EFFECTS
CRACK PROPAGATION
FIELD PRODUCTION EQUIPMENT
FIELD TESTS
GAS LIFTS
HYDROGEN SULFIDES
MATERIALS TESTING
OIL FIELDS
PERSIAN GULF
PIPES
STRESS CORROSION