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Shell Prelude Problems? Good luck guys!

FURTHER EXPERT SPECULATION ON THE ARTICLE: Shell’s giant floating LNG facility Prelude set to ship first cargo when mooring issues resolved

The mooring failures are indeed a concern but it is very doubtful they were the main contributor to the startup delay even if they are “shoehorned” into a very congested construction.

The process design is a well proven, a design in use in many of the LNG plants in many countries.

From past experience, I would suggest the main delay in startup after the certificate of fitness, or approval of the authorities, could be allocated to the startup of the wells.  During the drilling of the production well it is inevitable that drilling fines and drilling fluids will have percolated into the reservoir and quantities will remain despite all attempts to “clean up the well” have been completed.  The well well completion will possibly have been handed over with diesel in the string and Xmas trees.  We then have to consider the subsea pipework from the wells to the collection manifold and the subsea piping to the subsea point close to the Prelude and up the umbilicals to the swivel and on into the process. At the startup there inevitably will be “free water”  somewhere in the system which may have overwhelmed the dryers. Cryogenic operations and water are not good bedfellows.

Normally on startup this unwanted drilling fines/diesel/water will find itself somewhere in the process system causing absolute mayhem.  This may need certain portions of the plant to be dismantled to clear the issues or perhaps extensive problems with hydrates which can and will completely clog the process, can occur.

Yes, the initial well will be problematic but the same thing will happen with each and every new well opened up.  Perhaps Prelude decided to clear all individual well start up issues sequentially hence the extended delay on operational start-up being accomplished.

The whole startup of Prelude must have been a nightmare to the people who had the task of “getting the show on the road” and hopefully they can relax a little but remain ever vigilant.

Good luck guys!


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