drill pipe joint
The pup joint is an integral part of the drill pipe.
I guess which is divided into a male joint and a femalejoint,andisconnected to both ends of the drill pipebody.
I was each pipe is connected by the thread connections on the joint.
During the drilling process.the joint should be disassembled frequently,and the surface of the joint,is subjected to a considerable tong bite force.
So the wall thickness of it is big pup joint,and OD of the joint is bigger than that of the pipe.
I using higher strength alloy steel.
Domestic drill pipe joints generally use 35CrMo alloy steel.
The connection of the thread must meet three conditions,that is,the size is equal,the type of thread is the same,and the male and female are matched.
Different sizes of drill pipe have different joint sizes. I had the thread type of the same size drill pipe is also different.
The types of joints used by drill pipe manufacturers,are also difficult to be completely consistent. Therefore, in order to facilitate the distinction between drill pipe joints,and engineering applications.
API has made uniform regulations on the types of kelly sub, forming an API commonly used in the petroleum industry.
I have API kelly sub are available in both old and new standards.
API pup joint is proposed for the early use of thin thread drill pipe, and it is divided into three types:
inner flat type (IF),through hole type(FH)and regular type (REG).
I have the inner flat joint is mainly used to thicken the drill pipe.
Its characteristic:is that the inner diameter of the drill pipe,is equal to the inner diameter of the thickened part of the pipe body,and the inner diameter of the joint,and the flow resistance of the drilling fluid is small.
Which is beneficial to improve the water power of the drill bit.but the outer diameter of the joint is large,easy to wear.
The through-hole joint is suitable,for the inner thickening of the drill pipe.
The resistance of drilling fluid flowing through this joint is greater,than that of the inner flat joint.but its outer diameter is smaller than that of the inner flat joint.
Regular joints are suitable for internally thickened drill pipes.The inner diameter of this joint is relatively small,smaller than the inner diameter of the thickened part of the drill pipe.
Therefore, the drill pipe connected by the regular joint has three different inner diameters.
The resistance of drilling fluid flowing through this joint is the largest, but it has the smallest outer diameter and greater strength.
I regular joints are often used,for small diameter drill pipes and reverse drill pipes,as well as drill bits,fishing tools,etc.
I was the three types of joints all use “V”-shaped threads.
But the buckle type,(represented by the flat width of the top of the thread)is very different in pitch, taper and size.
- I was through-eye FH and XH are not common in tool workshops, nor are they commonly used.
- Commonly used are inner flat IF and regular REG, the differences are as follows:
- 4 buckles per inch,the relative buckle is thicker,and the taper is smaller.REG 5 buckles per inch, the relative buckle is thinner, and the taper is larger.
- IF buckles range in size from 2-3/8″ to 4-1/2″, larger than 4-1/2″ without IF, usually REG, and above 7-5/8″ without REG.
- Commonly used representation methods:
- I have represented by three numbers, such as 310, 410, 411, etc;
- The first number indicates the size (usually 2~7): 2—2-7/8″, 3—3-1/2″, 4—4-1/2″, 5– -5-1/2″, 6—6-5/8″, 7—7-5/8″;
- The second number indicates the button type (there are 1, 2, 3), 1—IF; 2—FH; 3—REG;
- The third number indicates male,and female (represented by 0 and 1) 0—female buckle; 1—male buckle;
- Other common drill pipe buckle types are BTC, MT, AMT, HT55, etc.
- In addition, the common buckle types of motors are 7-5/8″REG, 6-5/8″REG, 4-1/2″REG, and 4-1/2″IF. The common buckle type of scraper and hydraulic cutter is REG.
