Platform shutdowns 2

[murr52]

Any one have a rough estimate of how many times a platform lets say in atleast 3000 ft of water would need to shut down each year for maintence and weather combined or even just maintence?

Trying to get an idea how many times they would operate some equipment that would only be used during startup and shutdown of the platform.

 

[gerhardl]

Impossible to answer?! The downside end of the scale would obviously be zero, the uside depending on a lot of variables, location, type, construction, age, weather...etc, and on top of that all installations are built to give a minimum of downtime, and built more and more dependable.

You will probably have to go for your answer another way, depending on what you want to use the answer for.

Why not make some stipulations and stating your reasons for selecting this numerical data, and go from that?

As downtime is low, and statistical base data probably scarse, you will anyway have to use wide margins on your result to mime possible chances of reoccuring shutdowns within a given timeframe.

 

[JLSeagull]

A platform in 3000-foot water would be a large platform. What kind of platform? What part of the world? Does the question pertain to drilling or production and processing? Look on the web for the subsea stuff associated with the big deep-water GoM platforms such as Thunderhorse, Atlantis, Nikika. Is this off Brazil or other exotic parts of the globe?

There are shutdowns and there are shutdowns. Various parts of the process may trip on a routine basis. A total black situation would be limited to fire or similar severe situations. A maintenance turnaround like done in refineries would be less frequent as the platform should perform lots more routine maintenance. Also, if modular, individual trains or equipment packages can be serviced without taking the entire facility down.

With the previous impossible response, an easy "throw-down" answer would be different during commissioning and initial operations compared with a year later during stable operations. Consider budgeting for three total shutdowns per year during the good times, 13 when less good and hope for one every seven years. That covers the superstitious numbers. A long-term outage would be 40-days and 40 nights.

 

[sy123]

Well lets look at different factors that play-in when you want to shutdown a deepwater facility:

1) Installation Phase
2) Operating Environment
3) Failure of Equipment ( Normal house-keeping)
4) Unforseen Accident
5) Upgrades to platform



1) Installation Phase : I presume that you are dealing with a floating structure and in 3k water depth you would normally be looking at a Spar, TLP or a Semi. Eithercase, you dont have to worry about facility shutdowns in this phase as you wont be producing anything at this stage. And since this is a one time scenario for any platform, you can conservatively assume that the platform shutsdown once (1) or twice (2)

2) Operating Environment : Well this is kinda tied up to the platform you are using and the where it is located at.

If you are in either west africa or asia, you dont have to worry too much about the environment as you wont see any strong currents or decent wave dynamics in these locations. And that statement is valid if you are using a floater, but if you are using an FPSO then its a whole different story. You need to worry about the swells and other troublemakers. I dont have any particular statistics in-hand but I would say this factor will be a showstopper once every year

Now, if you are located in G.O.M then its a whole different scenario. In G.O.M they wont let you operate the facility if your current shoots above a 10yr return period. And worst of all with the kinda of tropical storms we are getting hit by these days, between July & December we witness atleast 3 of them every year and in a worst case scenario like 2005 we had to shutdown our rigs almost every other week.So thats more like 10 ~ 12 times every year. And if you have wave sensitive concept like a semisubmersible or a TLP then you can throw in an additional 20% downtime so that makes 16 times a year.


3) Failure of Equipment : Well this is a tough one because this is driven entirely by the kind of platform you put to work. Well if you have a Spar platform in that kinda of water depth, its perfect for the job as you wont see any issues related to SCRs joints or your rig accelerations or busting your aircans or tensioners. Well atleast in my experience I have seen one occasion where they have to stop production due to production equipment failure ( I guess its Chevron Genesis that ended up being a troublemaker for while). Well in that sense productions systems on TLPs also fare well ( until you hit really big stroms and end up turning upside down like that Atlantia TLP). But if you have a semisub in a 3,000ft of water the darn thing is going to give you all kinds of trouble begining from SCR joint failures to unmanagable rig accelerations. So I would say depending on the type of platform you may end up shutting down your facility anywhere from 0 to 4 times every year


4) Unforseen Accidents : Well this one needs to be estimated based on accident stats from previous projects. Well from my experience I havent seen any major issues on floaters being operated in GOM in past 8 - 10 years, mostly because we usually have good safety standards. But if you move into asia or other recently emerging places then this is a frequent thing in there ( esp ..S.E.Asia)

5) Platform Upgrades : Well again you have to think about what kind of upgrades we are talking about that could end up as show stoppers

a) New topsides process facility installation ( this couldnt be frequent thing with any floater , so lets say...conservatively we might do upgrades 3 times in a 20year life of the platform)

b) You want to add production systems to the platform ( like additional air-can or a top tensioned riser ) . well this depends on the additional capacity you have on the platform and what your production management procedure is going to evolve into. So from my experience ..anywhere between one to three times in a platforms life time


Well you can add up the numbers depending upon the five factors given above that are specific to your particular problem.


Good Luck!