Corrosion onshore facilities

Oil and Gas Production This sector is a major user of corrosion monitoring equipment, in particular for offshore fields where ramifications of corrosion and consequent maintenance are far more serious and costly compared with onshore production. Carbon steel is used for approximately 70-80 70 of production facilities. The development of a field is assessed on a defined corrosion risk which may not be correct, leading to serious corrosion. In addition, a reservoir may become more corrosive as the field is extracted owing to (a) increased water content, and (b) eventual souring of the field (hydrogen sulphide production). 

The first commercial Twister installation was implemented by Pefronas and Sarawak Shell Berhad (SSB) on the Bll offshore gas processing facility in Decanber2003. The unit dehydrates bOOMMcfd of non-associated sour gas fed to the onshore Malaysian LNG plant at Bintulu, to control pipe corrosion, and has at the time of writing being in continuous operation since start-up with over 99% availability. Table 9.1 compares capital expenditure for the Twister and other options for offshore gas development... 

Process hazards analysis (PHA) techniques were developed for the onshore chemical and refining industries. These industries typically work with a much wider range of chemicals than are used offshore, and many of those chemicals are highly toxic and/or corrosive—something that is rarely a major consideration offshore. Therefore, the use of onshore-style PHA methods when analyzing the risks associated with offshore facilities can feel like something of a misfit. Where possible these techniques should be modified so that problems to do with hazardous chemicals receive less prominence, but other issues—such as dropped objects and escape and evacuation routes—are analyzed more thoroughly. 

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