Drill Pipe / Casing Buttress Connection

Please stop referring to drill joints as casing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

API threads (American Petroleum Institute) are what you should be using simply because they work and always work.

The API fine threads are there because a fine thread pipe jioint is stronger than a course thread pipe joint.

If you use the course thread it will be lost in the hole in short order.

The thread lube is there for A REASON. If you are using a top head rig who ever is operating it should slow down the rotation while connecting drill rods period.

Before this gets any more deviated like a badly air drilled water well with a casing that is deviated from 180 degrees-

Are you mud drilling or air drilling with foam/water mist?

Is the drill rig a top head drive or table drive?

Are you using an air hammer or a tricone bit?

If you have a tricone bit are you using a centralizer weight joint above the tricone bit?

Are you using a casing spinner to connect drill rods or a winch and wrapped chain?

What is the drill rotation speed?

What is bottom depth?, or is this hole for exploration only?

What is the desired diameter to the bottom of the hole?

Are you using just one casing size range or are you using range one,two, and three?

If you are having problems with the threads it is one of two things-either poorly trained drillers, bad drill joints, or poor equipment condition as connecting drill joints can only go together so fast.

The tapered joints are stronger and the butress joint will fail from torque loads.

Thanks for your reply mtararat,

Please tell me what API thread standard you are referring to.

I cannot answer your drilling questions due to not knowing the clients operations.

My task was to design a QUICK CONNECT (CASING) connection (9 5/8) the client requested a buttress thd form.

I do know this connector will not be used for drilling and will stay above the drill floor.

A pointer to that API spec and any other would be appreciated

Thank you

I still would like to know what the blazes he is doing- with the casing and what method of drilling they are using so I can understand why you are required to do this for them- anything and everything relating to standards adopted by the API is available on the API web site the last time I checked- also drill rod suppliers on the web have alll their sizes listed etc.

If you want a quick reference for casing pipe go to the LB Foster web site for pipe, well casing.

OK stupid question time- why is a casing pipe coupler not being used as it is standard

procedure for threaded casing joints?, the coupler is straight threaded-usually 8 threads per inch for any given diameter casing.

Now I think I know what they are doing-they are pounding the casing in the ground-the drill and drive technique-they are asking for trouble with damaged threads from this-apparently they are not pounding the fully seated casing coupler which is the normal procedure -not something I would do as I am a fond believer in mud drilling-if it is possible please find out more information.

Well from what I can gather they want to connect a special casing sub on or above the drill floor for a wireline. This casing will be connected to my quick connect, my quick connect then attaches to a kelly valve. This sub is in a form of a 'y' to allow the wireline to enter. I have not been given any other info. I presume that drilling ops have been completed but this all seems quite odd so I'm still unsure.

As for using off the shelf casing pipe couplers there does not seem to be anything available to meet the clients needs. Hence where I come in.

If you know of a quick connect for a 9 5/8 that can hold a 600000 pound tensile load subjected to a internal pressure of 5000 psi please let me know.

Further to our the thread form the client requested I use it would seem that the API refers to the Buttress standard which for that size of diameter states 3 options to choose from for the TPI. (3,4 or 5 tpi)

Calculations indicate that 3tpi over 9inches will hold the 600000 pound load however if this is to be a quick connect then would need a 3 start thd which will need me to probably design a back off device (perhaps a spring lock tab)

I would get thee in haste to gefco in Enid Ok., as they would be a good fabricator for this animal-it sounds like a job for people that make the kelly swivels of which there are about a dozen at least on this side of the pond such as gefco www.gefco.com -(580)-234-4141

first ask the client about the well head and whether it is completed to bottom depth and if the are going to directional drill for gas extraction/ opening up the gas bearing deposits then call gefco first in any case and tell them what it is you have to do and they will most likely be able to help you with this situation as they are experts in mud drilling technologies and fabrication of piping for same.

It sounds like they are using wire line to directional drill for additional methane gas extraction.

Thank you very much for the heads up kind sir.

sure anytime, I would love to know what they are doing, a picture of the wel head would be great, do they have a christmas tree/blowout preventer on that well head already?

If I get anymore info I will let you know.

to re-cap

Their 9 5/8 "Y" casing connects to my connector at the bottom then my connector connects to a kelly valve. The "y" branches off for the wireline that has its own BOP. As for the run I only know it flows straight into more 9 5/8 casing up to who knows where.

As I said I will let you know if and when I know.

What do you know about kelly valves?

Thanks again

do you actually mean kelly swivels? the swivel rides up and own the square kelly bar alllowing mud to be pumped in or to allow mud to be pumped back up the drill string while using reverse circulation drilling.

There is the million dollar question, their info stated a 9" Kelly valve, single crank 16 3/4" OD body, 11" OD Neck.

option two:

Have fun- www.wncovalve@cableone.net 432-362-6160

One overstuffed check valve for drill strings-they can not be lifted with the kelly-they are only ment for mud control in the string and control of the mud in the annulus.

I guess they are more worried about a blowout/drill string jumping/mud surge through the string or they do not have a lot of water for mud.