ABSTRACT:

A short abstract (50 to 100 words) in a single paragraph should be Steel catenary risers (SCR) for deepwater offshore oil and gas field developments are subject to seawater on the external surfaces, produced fluids on the internal surfaces and to fatigue damage associated with wave or tidal motion and vortex induced vibration. Risers and pipelines are also exposed to potentially aggressive service environments on both the inside and outside surfaces. The corrosive effect of seawater on the external surface is typically controlled by the application of cathodic protection. However, this can lead to hydrogen generation on the steel surface, and degradation in fatigue performance needs to be accounted for in design. The presence of salts and water, acidified by presence of carbon dioxide and/or hydrogen sulfide, all contribute to the aggressiveness of the environment. The influence of environmental factors on corrosion fatigue behavior has not been well revealed in sour brine environment. In order to quantify corrosion fatigue crack growth rate (FCGR) test of low alloy steels in various environments, the effects of environmental factors on corrosion fatigue properties have been evaluated under several corrosive environments.

INTRODUCTION

Steel catenary or top tension risers are widely used for deepwater applications and are subject to fatigue damage associated with wave or tidal motion, vortex induced vibration (VIV) and operating loads (BS7910, 2005; DNV-RP-C203, 2005). When the produced fluids are sour (i.e. contain water and H2S), higher fatigue crack growth rates (FCGRs) are expected, and therefore, shorter overall life compared with performance in air (Buitorago, 2002; Hudak, 2010; Thodla, 2010). Successful design is critically dependent on the availability of appropriate experimental data to quantify the extent to which fatigue lives are reduced, and rates of fatigue crack growth are increased in a sour environment.

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