Use this URL to cite or link to this record in EThOS:
Title: Mechanical behaviour and stress corrosion cracking of super duplex stainless steel pipes in high pressure and high temperature environment
Author: Lasebikan, B. A.
ISNI:       0000 0004 2709 5425
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2011
Availability of Full Text:
Access from EThOS:
The oil and gas industry is constantly looking at ways to keep costs down in high temperature and high pressure (HPHT) well completions. The use of duplex or super duplex stainless steel (DSS or SDSS) for production tubing rather than high alloy (austenitics or nickel based) steels is one way to achieve this. An effective use of DSS or SDSS requires an understanding of the effects of environmental and metallurgical variables on the general and localised corrosion behaviour and resistance to environment assisted cracking (EAC) in HPHT well conditions. This research investigates the behaviour of small scale SDSS pipes subject to combined loads in a chloride and sulphide environment which are commonly found in the non-production annulus of oil and gas well completions. The effects of H2S (which can sometimes leak from the production fluid) on the chloride-based fluid and ammonium bisulphite in the non-production environment is examined. This is used to provide a realistic assessment of the type of fluid that SDSS production tubing may be exposed to in service. Experimental results are presented for the failure envelope under combined internal pressure and axial tension, and mechanical properties of SDSS pipe over a range of temperatures. A standalone autoclave was designed and commissioned to study the initiation of EAC in SDSS pipes in several aqueous solutions under a range of loading conditions: internal pressure, axial load, and a combination of internal pressure and axial load. The work presented in this thesis shows that corrosion tests can be carried out using small scale pipes for better understanding of the effects of stress state on corrosion behaviour. In particular, the safe working envelope of SDSS in terms of load combination, chloride-sulphide environment and temperature is determined in this thesis. This would help the end user understand and gain better in-service performance of SDSS in oil and gas HPHT environment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available