Question In chokes what does the term 64ths means how does this term derived why not 24 ths or 124ths or 256 ths how did they derive the term for sizing
Answer Hi Dinesh,
I don't know. I must admit that I have never really thought about it and am now wishing I had asked some of the old timers that were around when I “broke out”.
The increase in size is not uniform; it is by 1/64 inch until the 30/64th size and then jumps by two or three 64ths. Since the inch diameter increase is uniform, 1/64, the decimal equivalent is also uniform, 0.157. The flow coefficient does not, this is logarithmic increase and was something easily found on an old fashioned slide rule. This would not tell why 64ths as the same thing would apply to other uniform increments.
Chokes have been around since the 1930’s and the invention of the christmas tree. I would suspect that 64 of an inch was used in order to get good flow adjustment without having too small or too large of pressure changes at each choke change. In other words, trial and error for 64ths as opposed to 32nds and a smaller size would bring in machine shop difficulties as these early chokes would have been made by drilling hole with a bit. Smaller than that would be a fragile bit.
In my profile I state that I will not do someones web search for them but this has me puzzled. After an hour Googleing I found nothing on the subject. I called one of my business partners and he didn't know. I have enclosed a link from an engineering company that shows both positive and adjustable chokes and on page 29 of the 40 page document you can see how the sizes change.
Do NOT ask me questions about LEASING, MINERAL RIGHTS, ROYALTIES, POOLING, etc. I am not qualified to give accurate answers on these subjects.
If you DO ask, I will NOT answer!
I CAN help you understand the technology and equipment involved in drilling oil and gas wells on land or offshore and the production process after the well is drilled. I prepare the programs for the rigs that get oil and gas out of the ground and direct activities on the drill rig so questions concerning the engineering process and preparing drill sites and roads or marine transport are welcome, those concerning the legal process less so.
I work with wells on land or offshore, U.S.A. or other countries. I can also answer environmental, regulatory and safety practices questions.
35 years working in the 'Patch' all over the world. I have drilled for oil & gas on land and water in the U.S.A, Brazil, Guatemala, Nigeria, South Africa, Angola, Tunisia, England, British North Sea, Iran, Oman, Pakistan, Vietnam, Philippines. I have drilled in water depths up to 2000 meters and on land in desert and artic conditions. Some were in countries where environmental and safety concerns were non-existent and others when they were primary. I have certification for well control/blowout prevention, have attended water/helicopter/boat survival school and am certified for spill cleanup. I am currently working as a consultant for drilling projects and spend half my working time at the drill site and half in my office and most of my "off time" traveling between the two.