The ability to optimise the use of carbon steel in sour service presents man y economic advantages, including minimizing the use of expensive corr osion resistant alloys, enabling optimised large bore completions, and eliminating addit ional offshore facilities. An integ rated approach to corrosion modeling and testing has been d eveloped to reliably extend the ap plication of carbon steel. Key elements of this integrated approach include: (1) ri gorously establish tubular environmental conditions, (2) accurately simulate environmental conditions (acid gas concentratio ns (CO 2 /H 2 S), water c ut, and water composition) in the laboratory, (3) mathematically extrapolate laboratory weight loss and pitting to predict tubing life, and (4) validate tubing life predictions with field caliper data. This paper describes the application of the inte grated approach to evaluate L80 tu bular corrosion and predict tubing life for a range of a cid gas (CO 2 /H 2 S) concentrations. The pape r also discusses the corrosion mechanisms and validation of predicted corrosion with field caliper data.

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This paper discusses an approach used to assess liquid film erosion/corrosion effects in the tubing strings of sour, high-rate, wet gas producers. This was done as an alternative to API RP 14E, which utilises an empirical erosional velocity factor "C" to estimate maximum velocity limits to minimise the potential for tubing metal loss from erosional effects.Many RasGas wells are completed with a full L-80 carbon steel or a combination L-80/Corrosion Resistant Alloy (CRA) production string. Once on production, a thin iron sulfide scale develops on the tubing wall significantly retarding the rate of metal loss due to internal corrosion. However, shear stresses generated from the condensate/water film flowing along the tubing wall could potentially remove this protective iron sulfide coating and expose fresh metal to much higher corrosion rates. This paper describes the approach adopted to assess the magnitude of shear stress created across a range of flow conditions including well production rates, fluid properties, and completion sizes using transient 1D flow simulation and more detailed 3D computational fluid dynamics modelling. The results will be used to design future laboratory experiments to assess the effect of these stresses on the integrity and effectiveness of the iron sulfide scale in reducing corrosion rates.