Sites: GlobalSpec.com | GlobalSpec Electronics | CR4 | Electronics360
Login | Register
The Engineer's Place for News and Discussion®

Previous in Forum: Gelsight - awsome sensitivety !   Next in Forum: Drying a powder
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







25 comments
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16

Critical Spares

09/19/2009 8:13 AM

Hello all, I have recently been asked to build a spread sheet consisting of "critical spares" needed to be kept on board various off shore drilling rigs in my charge. This is not the first time I've been down this road, but the result seems to be much the same each time! The list is a virtual "Pandora's box", as most every part on the rig is critical and can cause down time if not on hand functioning properly.

Do you guys deal with lists such as these in other fields? If so how do you differentiate between the critical and non-critical spares?

I am hoping that some differnt views on this subject may help somewhat.

Register to Reply
Pathfinder Tags: Critical Spares
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 11069
Good Answers: 139
#1

Re: Critical Spares

09/19/2009 9:10 AM

You done it before.

Your have to rate the spares. Can a/one part shut done production. That is a critical spare.

Can a part impede production but not shut it down. That brings other issues to bear. Is the part easily available such as on site with in 24-36 hour. If yes, may not be a problem. If its one week to have on site it may push it from a non-critical to a critical item.

Thats up to you to rate it.

p911

__________________
phoenix911
Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#2
In reply to #1

Re: Critical Spares

09/19/2009 9:18 AM

Logistics play a big part as we are operating about 100 miles off the coast of Brizil.

24-36 hour shipment is almost un heard of even if the part is on shore local. BUT there are only so many parts you can hord on board a rig. So its a fine line to walk.

Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 11069
Good Answers: 139
#3
In reply to #2

Re: Critical Spares

09/19/2009 9:26 AM

I do not know what your situation is I just grabbed the 24-36 time frame try a 36-60 hour or what ever time frame it is; BUT there are only so many parts you can hord on board a rig. and maybe if you already have a off-site storage. Do not know the size of the operations

You may even bring that up in rating critical and non critical parts.

Everyones capabilities and criteria are different. And that fine line you talked about....you only actually know were it is after you have crossed it.

good luck

p911

__________________
phoenix911
Register to Reply
Guru

Join Date: Aug 2007
Posts: 1803
Good Answers: 87
#10
In reply to #2

Re: Critical Spares

09/20/2009 1:03 AM

You should not be worrying about hording parts on board. That is futile. You need a good shore base with climate control and then you put your spares there. Then 24 to 36 hours is easily achieved.

The other thing to keep in mind is how does the company track things. In the old days no one worried too much about production deferrment. If you did not pump out the oil today, you could pump it out tomorrow. In that environment I have seen FPSO's out of service for a couple years waiting on repairs.

Register to Reply
Guru

Join Date: May 2007
Location: Ohio. USA
Posts: 564
Good Answers: 30
#4

Re: Critical Spares

09/19/2009 3:31 PM

Another thing you must weigh is the availability of the spare part. If a part would: 1. Shut down your operation. 2. You know it does at times break or wear out. 3. Is long lead time (custom made components not on the shelf) then this is usually the kind of part you would have to keep on hand either with the rig or at on shore storage.

If the same company services several similar rigs you might try common on shore storage of expensive parts to keep duplication costs down. That is provided you can live with the helicopter or freight delivery time.

To actually find the high usage items or to determine the usage of common items like certain bearings, pump impellers etc. you may need to grind thru maintenance or purchasing records. Not fun but possibly necessary.

__________________
I won't belong to any organization that would have me as a member. Groucho Marx
Register to Reply
2
Power-User

Join Date: May 2006
Location: Bahama, NC. USA.
Posts: 184
Good Answers: 11
#5

Re: Critical Spares

09/19/2009 11:49 PM

Tim in Mexico I have had to do this for machinery on a production floor where a lot of the parts came from across the pond and the lead time could be months so its difficult due to the expense involved. Normally after making my recommendations I would be told to break it down into multiple purchases to be spread over a year or more with the most critical ordered first. One thing I would consider is the ability of our machine shop to make a part, the availability of raw materials. A good machinest can be a key player in making or repairing parts to keep the wheels turning until spares can be obtained. A lot of times we would be abile to rob parts from other areas to get us through and when all else fails pick up the phone and start calling your competitors parts department, you would be surprised how many times a stock room manager will ship you something off the record so he can establish a parts source that can keep his but covered in times of desperate need. With the cost of down time I would leave no stone unturned, we have turned to the internet many times with good success. J.Conway

__________________
For every great advancement in medicine there is an equal and opposite advancement in the denial of treatment.
Register to Reply Good Answer (Score 2)
2
Guru

Join Date: Oct 2008
Location: I'm outa here
Posts: 1933
Good Answers: 196
#6

Re: Critical Spares

09/19/2009 11:50 PM

Tim -- This is not a trivial project. Sitting in your seat I'd approach it as follows:

Collect all the anecdotal information you can from the operational people including managers. That way you'll know their hot buttons and what equipment may already be causing them problems. They are your "customers"

Next put together an equipment list with model numbers and manufacturers. If you can get help from the major contractors who engineeried and built the platforms they should have records that may include recommended spare parts list for each model. If not, contact the manufacturers and try to talk to parts managers and field service engineers if possible to see if there are service bulletins relative to specific equipment models. Note that recommended spare parts are not often listed in instruction and operation manuals.

A facility as big as a drilling platform should have some kind of preventive maintenance program and someone in charge of making it happen. Get copies of those plans. You'll want to know which items are on the list for periodic replacement like filters, seals, rigging gear, bearings and electrical components. Don't forget the multitude of fluids and fasteners that need to be stocked to support machinery maintenance as well as the stuff the electricians need. There will also be a lot of communication and control hardware as well as the stuff needed for domestic services like food preparation to keep the crew happy.

If possible make the acquaintance of someone with US Navy experience in supply, ship systems or facilities engineering. You may be suprised at what you find with some internet searching. They have had generations to develop some excellent programs for managing these programs to support the fleet as well as Navy shore installations. They are definitely world class.

Ed Weldon

Register to Reply Good Answer (Score 2)
Power-User

Join Date: May 2006
Location: Bahama, NC. USA.
Posts: 184
Good Answers: 11
#7

Re: Critical Spares

09/20/2009 12:04 AM

Tim in Mexico One thing I failed to mention is knowing where all your parts are. If the inventory shows 0 available then check to see who has requisitioned the part needed in the last several months or year, they may still have one stashed in a tool box or elsewhere. Many times mechanics will do this on frequently used or hard to obtained parts. J.Conway

__________________
For every great advancement in medicine there is an equal and opposite advancement in the denial of treatment.
Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#8

Re: Critical Spares

09/20/2009 12:34 AM

Jerrel and Ed,

Your thoughts on this make me think that you have certainly been here before...

Most of the rigs have limited machining capabilities, one of my thoughts was to up the capabilities as far as different bar, hex. etc. stock in various alloys as well as ensuring a complete set of key way broaches are on hand rather than maintaining a stock of specific parts.

As far as getting rig managers to actually share there thoughts in a form that they may in some way remotely be held accountable to... NOPE.

I suppose thats what it is in other industries as well, they either don't want to show everyone how little they know or don't want to be accountable, or both.

It is very helpful to hear other peoples thoughts on a subject as this to ensure one stays focused on the important aspects and does not loose focus.

I very much appreciate your comments and will take them as good advise.

Regards,

Tim

Register to Reply
Guru

Join Date: Oct 2008
Location: I'm outa here
Posts: 1933
Good Answers: 196
#11
In reply to #8

Re: Critical Spares

09/20/2009 1:45 AM

Tim -- your comment "As far as getting rig managers to actually share there thoughts in a form that they may in some way remotely be held accountable to... NOPE." reflects a chronic illness in your employer's gut. But like a storm at sea you can't change it; so you just ride it out.

The drill rig has a mission, right? To drill and likely a few related things like data collection, meet environmental and safety requirements, etc. The manager's job is to complete the mission. His operations capability is needed to get the job done. In every organization I've ever been associated with operations is number one and anything that breaks or quits is the boss's problem. They get very interested in anything that slows or stops that mission. I view a drilling rig as being very much like a ship at sea. If the guy on the rig (in the Navy we called him the Captain) doesn't do everything humanly possible to complete the mission within the framework of orders and regulations then you've got big problems. I visualize those guys as being very passionate about having spares support for specific problem areas on the rig that have a history of failing and causing the drilling to slow or stop. Someone, if not you then one of your superiors, needs to get into "off the record" conversations with those guys to find out about these areas that need special support.

For example you can blindly set up a stocking level for mechanical shaft seals for all pumps at one per pump. If you have a situation where a leaky seal is a problem that can wait till next week on 95% of the pumps; but the other 5% will quit pumping and shut the drilling down in case of failure you need to know that. Otherwise you will burden the spares inventory (and your own efforts) 10 or 20 times more than necessary for that class of part.

RE your comment about machining capability: You can overdo that stuff. If a set of keyway broaches will enable you to substantially reduce the inventory of shaft couplings, fine. But if the program also involves a lathe to precision bore the different size shaft holes then you'd best have justification for that tool and all the stuff (including the skilled machinist) that goes along with it. And if they are wearing out or damaging couplings and other hub like parts they are probably damaging the shafts they mount on. How are you going to deal with them? There are hundreds of different maintenance situations on the rig that require that level of your attention. Are you ready and more importantly, competent to get into that level of detail?

By the way, I didn't address safety and environmental compliance equipment support. Depends on the operating rules. If your company's operating rules put production into a shutdown mode when safety and such rules are not being followed then the gear that supports that stuff becomes mission critical also.

By the way, your initial question about critical versus non-critical really needs something better than a "black and white" distinction. Some math is needed and I think that is where your spreadsheet comes in. (I don't think the spreadsheet is a good idea for managing individual part inventory control.....to many items for that). Anyhow the best approach to me is a financial approach. Managers all understand the meaning of costs. For each item or class of items figure the frequency of failure or scheduled replacement, the time to repair and the resultant cost of lost production. Compare that to the cost of materials and labor to make the repair. The material cost must include the inventory costs. This is usually some fractional multiplier of the purchase cost of the repair part added on to the purchase cost to cover purchasing activity, cost of storage facilities and management and the cost of the financial capital tied up in the spares inventory. The company financial department usually has that number. A dozen or two sample calculations like this will give you a better picture on which to build your strategy than all the comments we can give you.

Ed Weldon

Register to Reply
Power-User

Join Date: Jul 2008
Location: India
Posts: 457
#12
In reply to #11

Re: Critical Spares

09/20/2009 5:36 AM

Is anybody having critical spares list format for example.

so that I can draw mine for my machines.

__________________
thoughts becomes things.
Register to Reply
Anonymous Poster
#9

Re: Critical Spares

09/20/2009 12:47 AM

I feel your pain Tim. I perform this same function on semiconductor equipment. At 10K an hour down time they get upset when we don't have parts. It does seem like most people have given you much the same advise I could but her is a brief list anyway. 1) Know your failure rate of parts. High failure rate, keep more of them. 2) High dollar parts, asses failure rate risk vs down time/storage costs 3) Long lead time parts 4) Parts you can fabricate on site 5) You mentioned other rigs, a coordinated efforts is a really good approach High dollar parts - push vendors to stock, low dollars, spread them around and share.

Register to Reply
Power-User
Engineering Fields - Systems Engineering - Member for some time now, see my profile.

Join Date: Aug 2007
Location: Essex, UK
Posts: 367
Good Answers: 3
#13

Re: Critical Spares

09/20/2009 11:11 AM

Tim,

you are receiving a lot of solid advice.

You must know statistice or failures of all parts and replacement times from suppliers.

The replacement time is a factor that you need as some parts, as you say, are less critical than others. I have been here before as a supplier of long haul communications to many rigs. Comms down, no operations was the rule.

One time a customer refused to hold a major item as stock.

It was a critical item and it failed around Christmas.

i got the call from the customer, what the hell do I do know, he said.

Factory was on holiday, so I had to call the guys out and they found the last spare that we held. This was shipped in a large vehicle by one of the guys who drove 500 miles, unloaded it and drove 500 miles home.

We got paid and he got back on the air and oil stared flowing within a few hours.

Yes he did buy another one as a spare!


Ultimately this story is about a customer that could not justify to his board one very expensive item and we had never had one of these fail before so we had no stats to make the case.

Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#14
In reply to #13

Re: Critical Spares

09/20/2009 11:40 AM

Yes I have gotten some solid advise. We have used the Maximo system for our maintenance program for quite some time, so that helps to gather stats on the equipment.

Then there is the practical experience as I started on these rigs as a mechanic and worked my way up, so as far as knowing what will in fact shut the rig down or put it in harms way is no problem.

On newer generation semi's they have began building much more redundancy into almost every aspect. Many even have two Derick's!

Now I'll get back to Tim's world... Equipment with no redundancy would be;

Derick traveling system (crown, traveling block, draw works, Baylor brake)

Top Drive and its related components.

Cranes

Ballast system (because if you are forced to rely on your redundant pump your a## is getting ready to be in a bind)

High Pressure mud pumps

RO water maker

Emergency generator (just because)

Most everything else can be dealt with until repaired, for instance there is normally at least one main generator on stand by, etc.

What really helps a great deal is just listening to others points of view on the subject.

Thanks you guys!

Register to Reply
Power-User

Join Date: Jul 2008
Location: India
Posts: 457
#24
In reply to #14

Re: Critical Spares

09/21/2009 1:48 PM

what is this maximo system?

__________________
thoughts becomes things.
Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#25
In reply to #24

Re: Critical Spares

09/21/2009 2:43 PM

Check link in comment #16. This explains this type of system, Maximo is one of many systems out there

Register to Reply
Power-User

Join Date: Jul 2008
Location: India
Posts: 457
#15
In reply to #13

Re: Critical Spares

09/20/2009 2:21 PM

You said-

You must know statistice or failures of all parts and replacement times from suppliers.

Is there any format to know this statistice or failure?

Please tell me any sample or format

__________________
thoughts becomes things.
Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#21
In reply to #15

Re: Critical Spares

09/20/2009 5:12 PM

I'm sure there are other trains of thought on this, but in my opinion you need to compile your stats from a great many different sources. Some of them are (but not limited to);

Maintenance program data (Maximo or the like). from this you will retrieve your PM and CM frequencies.

OEM recommendations

Your particular environment (hot, cold, wet, dry, dusty, etc.)

Availability of support in your area

Logistical issues in your area (transportation as well as customs)

Quality of your work force

And the list goes on and on, once you start to get your head around all the different aspects then you can start to come up with something.

It is in no way something you can do in a short time, it is normally the responsibility of the Asset or Maintenance Manager. The job is NEVER really finished either!

Register to Reply
Power-User
United States - Member - US Navy Veteran

Join Date: Mar 2007
Location: Nothing sucks more than that moment during an argument when you realize you're wrong.
Posts: 302
Good Answers: 22
#16

Re: Critical Spares

09/20/2009 2:21 PM

I don't know squat about the offshore drilling industry but I would like to pre-qualify my response by stating that (1) I'm a former machinist, (2) maintenance supervisor and (3) I've recently been task with maintaining 10 coordinate measuring machines (which I program in my free time) that need to be operational 24 hours a day 5 to 6 days a week requiring that we maintain critical spares.(but we can't get a PO signed)

IMHO - If you don't already have one, then a good Computerized Maintenance Management System (CMMS) would help by logging your repair activities. This type of program will assist you in analyzing and identifying what, and how many spares you need on hand in your store room as well as if it's web based, the possibility of seeing what your other rigs have in stock in there store rooms.

http://en.wikipedia.org/wiki/Computerized_Maintenance_Management_System

It seems logical that you would have an old school machinist/fabricator on board with a small shop containing a mill, lathe and surface grinder that could make almost anything good enough to get by....just keep'em locked in the shop and feed'em cheap beer till you need'em....they love abuse.

__________________
You never know when it will strike, but there comes a moment when you know that you just aren't going to do anything productive for the rest of the day.
Register to Reply
Power-User

Join Date: Jul 2009
Location: Montreal, Canada
Posts: 282
Good Answers: 18
#17

Re: Critical Spares

09/20/2009 2:38 PM

Hi, Tim.

You've had the great luck to receive excellent 'technical' advice concerning this, so I won't add to it.

One that that I WILL add to this is that you'd find it VERY effective to present your case in a way that's 'culturally understandable' in Latin America. I worked offshore in Brazil on Petrobras' oil-procuction platform, the P-36. Yes, the one that blew up, killed 10 of my colleagues, and sent their corpses to the bottom of the Atlantic.

Brazilian culture and those many other Latin American countries have strong currents of soft authoritarianism in them. What this amounts to, in very summary terms, is that 'You do what your boss tells you to, you do PRECISELY that, and you don't do anything else or more'. Also, when you're done, go to your boss to ask what to do next. Note that this is a generalization, but it's a VERY real one.

The above makes it VERY hard for Those Above to get a group 'below' them to organize themselves, undertake and maintain programs, etc. Those who rise in a system like this are those who were best in pleasing their bosses or in getting good diplomas; they're NOT necessarily those who are 'can do, get it done' types.

So, Tim: the way to get your point across is to use authority on platform managers. And the ideal way to do that is to tell them that they MUST do it, to inform THEIR bosses that it MUST be done (put it in writing!), and to tell them what will happen if it isn't done. This will get their attention. If, after a while, you don't get results, get YOUR boss, to talk to them ... they'll recognize him as having 'authority' and they'll likely act upon what you say. What it works out to is that very often your boss will have to talk to your platform manager's boss to get things done.

Once you've figured this out and how best to use it in your environment, you'll start getting results. For a true-life story from the P-36 platform, read my next post.

Cheers! DZ

__________________
Do unto others. Then run.
Register to Reply
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 662
Good Answers: 16
#20
In reply to #17

Re: Critical Spares

09/20/2009 4:43 PM

Very true words there DZ!

Not to be mis-understood, I've called Latin America home for a long while and most of my best friends are of Latin decent.

To me it seems to be personnel either very good or as you have quite well explained.

BUT on the rigs, I've made the statement more than once that "if you tell someone to jump you better stick around to tell him to come back down"

Thanks

Register to Reply
Power-User

Join Date: Jul 2009
Location: Montreal, Canada
Posts: 282
Good Answers: 18
#22
In reply to #20

Re: Critical Spares

09/20/2009 6:07 PM

True, true.

I have many Latin friends too; and they'll often be the first ones to tell you how difficult it can be to get things done in Latin America if one doesn't know how to go about it.

Cheers!
DZ

__________________
Do unto others. Then run.
Register to Reply
Power-User
New Zealand - Member - New Member

Join Date: Aug 2007
Location: Wellington, New Zealand
Posts: 185
Good Answers: 14
#18

Re: Critical Spares

09/20/2009 2:54 PM

You've received some pretty good advice but none of them mention the most important aspect - YOU.

It sounds to me as if all the s--t has been put in one bucket and left at your door. You need to be careful and protect yourself. When the rig is losing $eleventy million a day the spotlight will get very bright and the fingers pointed very sharply. Keep careful records of what you are doing and the methodology imposed. Write memos along the lines of "I refer to our telecon of the 14th. I appreciate that you cannot assist me i with part no. X but would ask if you could enquire further about who could help." You are then indirectly providing a paper trail to those who refused to assist. Any backup you have will assist when disaster strikes. You don't want your job or reputation sullied by the inadequacy of others.

__________________
I love deadlines; I love the whooshing sound they make as they pass by. - Douglas Adams
Register to Reply
Power-User

Join Date: Jul 2009
Location: Montreal, Canada
Posts: 282
Good Answers: 18
#19

Re: Critical Spares

09/20/2009 3:13 PM

True story from the (now sunk) P-36 platform off the coast of Brazil.

The platform had all sorts of problems starting up its three gas-fired turbo-compressors, so engineers from Britain and Italy had to spend several weeks on board just to get the first one started. (FYI - It wasn't the supplier's fault).

The engineers kept on getting p*ssed off at the Brazilian electrical/mechanical techs because 'they weren't doing what the engineers were telling them'. After a few weeks of this, I started putting things together in my mind: the engineers were asking the techs 'has this been done', 'has that been finished', etc. The Brazilian techs would always answer 'yes'; and of course, time was lost in trying to get the damn equipment to start, until the engineers would blow their stack, check whether the work had really been done, and found that it hadn't.

For example, once when the engineers were trying to start the turbo-compressors, they asked the lead electrical tech if the field-wiring in a junction had been done (the cables leading into the JB could be seen to enter it). The answer (like always, in similar situations) was 'yes'. The engineers then spent a good part of the day trying to start a turbo-compressor, but trhe damn thing just didn't want to start. The engineers eventually decided that the problem probably had to do with control signals. They went to the big junction box they had asked about, opened the front door, and boing-oing-oing ... out come dozen of unconnected wires. The engineers told the techs to make the connections, and then spent the rest of the day complaining to everyone that the techs AGAIN were worthless, yada yada.

The real problem was that the engineers and the techs understood the engineers' language to mean different things. A Brazilian tech (and I presume techs from other 'soft authoritarian' cultures) will always say 'yes', no matter WHAT the reality is, because he'll never presume to take responsibility for anything that he's not SPECIFICALLY told to do. (Which is justifiable ... if he does something that he hasn't been specifically instructed to do, his superiors will fall on him if he does something and he makes a mistake).

So, if you have 'authority' or 'legitimacy' over someone (engineers overs techs for example), you shouldn't ask if something's been done; you should say 'do this', 'do that', etc. It's a drag to North Americans and to West Europeans, who work in cultures where there's more personal responsibility. (I haven't worked in East European environments to date, but the sense I get from working with some people from there is that some people there think in 'doubly-soft authoritarian' terms ... they adapt themselves well to responsibility, but they have to get used to it).

Good luck!
DZ

__________________
Do unto others. Then run.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2008
Location: I'm outa here
Posts: 1933
Good Answers: 196
#23
In reply to #19

Re: Critical Spares

09/21/2009 12:34 AM

GA, DZ. Thanks for your analysis of the human component.

Ed Weldon

A dynamic universe consists of countless happenings. They only become problems when humans get involved.

Register to Reply
Register to Reply 25 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); BabyGuinness (1); DaveB (1); DreadZontar (3); Ed Weldon (3); Jerrell Conway (2); markar (1); phoenix911 (2); sandeep lokhande (3); Sleepy (1); Steve S. (1); Tim in Mexico (6)

Previous in Forum: Gelsight - awsome sensitivety !   Next in Forum: Drying a powder
You might be interested in: Drilling Rigs, Time Delay Relays and Solid State Timers, Time Servers