Casing Design

[vanket]

Thanks again! By the way, what is RKB-Subsea? and what is Wellhead Growth Index?

[yudhi]

Dear everyone....

I also read Rabia book regarding casing design, and i try to compare with another book about this same topic. but so far, all collapse and burst calculation is intended to determine weight and grade of each casing (either conductor, intermediate, production, etc)...

lets say if i wanna do casing design and i have well data as an input for grade and weight determination by collapse burst calculation, so what about the casing programme??? whats the reason to choose eg. 30/24/20/16 OD for conductor and others casing/tubing OD....

so far, i only saw that all calculation have mention already about casing progamme how to determine OD casing???

[vanket]

yudhi, I do not really know the right answer, but there is a hole size selection chart that can be seen from other books. I think that experience is one factor in choosing OD, but there are many considerations, like choosing a slim hole might be economical but has some disadvantages in well completion stage. Well i know what's your point, i've read many books about casing design and i've never seen calculations to determine the right OD. I prefer using programming, and do some randomization to find the best value my program can give, that will satisfy the conditions given, of course it must be economical.
I'm just a student and very new to this but that's all what i got for now.

[vanket]

yudhi, I do not really know the right answer, but there is a hole size selection chart that can be seen from other books. I think that experience is one factor in choosing OD, but there are many considerations, like choosing a slim hole might be economical but has some disadvantages in well completion stage. Well i know what's your point, i've read many books about casing design and i've never seen calculations to determine the right OD. I prefer using programming, and do some randomization to find the best value my program can give, that will satisfy the conditions given, of course it must be economical.
I'm just a student and very new to this but that's all what i got for now.

[jdmacbook]

Hi- the basic approach when designing casing strings is to start at the bottom and work back- keeping in mind that it is always nice to have a "contingent" string available if you are expecting hole problems. So step one should be to define your objectives for the lowermost casing string wrt sizes, then using your pressure data plots work back from there. Select the most economical hole and casing sizes as you select each string, again refer to your hole / casing size charts . There should be examples of this in all design manuals.

[oxygen21]

Hi,

I have some questions regarding the casing make up torque.
1) API or Non-API does effect the make up torque?
2) Can someone explain me about connections ; BTC, VAMTOP, VAGT, BLUE,etc
3) Different connections has different torque?
4) If you have spread sheet for the torque, kindly share me.

Thanks

[yudhi]

hi oxygen21,

i share what i know:
1. make up torque always specify by thread manufacturer (premium thread), for API connection also regaulted in API itself. you can read either API 5B or API 5C1 (i forgot which api it belong to, but i've seen it.)
2. BTC (currently become BC) is buttress [API connection], VAMPTOP and others are premium thread.
3. yes. like my no.1 explanation.
4. you can search to specific thread, those manufacturer shall state that information.

hope it helps

[mbc.engg]

Thanks

[vanket]

By the way, does anybody know how to calculate the collapse rating for Non-API casings? I tried to use the API formulas for determining the collapse rating but it did not produce the right answers. I Hope someone can help me! Thanks!

[BOUGHELOUM]

look to api 5c3 paragraphe 8.4, there are a non API grade -(grades indicated without letter designation).

[link Point to another website Only the registered members can access]

[vanket]

Thank you BOUGHELOUM! I've read the part you are talking about. But my problem is, when i tried to use the formulas in calulating the collapse rating of S80 and other Non-API casings from appendix B, page 349, Casing Design Theory and Practice by Rahman i did not get the same results.

[BOUGHELOUM]

S80 is a special grade and collaps limit is defined by manufacturer not by API formula.