Common API Drill Pipe Connection

Drill pipe is used to connect the surface equipment of the drilling rig to the drilling and grinding equipment or the bottom hole equipment at the bottom of the drilling. at both ends of the drill pipe body. Today, we will explore the commonly used API drill pipe connection types.

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There are four types of threaded drill pipe joints:

- REG (regular connection)

This type of drill pipe joint thread is used to connect the inner thickened drill pipe so that the drill pipe diameter is smaller than the thickened inner diameter and the thickened inner diameter is smaller than the inner pipe diameter. The main purpose of the API design for regular style joins is to apply to bit joins. Because the drill bit is located at the end of the drill string and has nothing to do with thread stress concentration phenomena, API retains all of its specifications.

- IF (internal flush connection)

This type of drill pipe joint is threaded to connect EUE or internally and externally thickened drill pipes to form the inner diameter of the drill pipe joint. The inner diameter of the pipe and the inner diameter of the thickened pipe are equal to the inner diameter or approximate size. All specifications use threaded V-0.065 flat top and flat bottom triangular profile with a width of 0.065 inches (1.651mm). Because this type easily leads to stress concentration, API has gradually replaced it.

- FH (full hole connection)

This kind of joint screw connects the inner and outer thickened drill pipes to form a structure in which the inner diameter of the drill pipe joint is equal to the diameter of the thickened end and smaller than the inner diameter of the pipe. Although there are not many thread specifications, there are three models: V-0.065, V-0.05, and V-0.040, which have been widely used in kelly pipes, drill pipes, drill collars, drilling tools, etc.

- NC (numbered connection)

For drill pipe with a minimum yield strength of 75,000 PSI or higher (high strength), API recommends an additional designation called numbered connections, or NC. NC is designed to join male and female couplings with matching thread designations and are largely interchangeable if the grade codes match, i.e. the thread pitch is the same and the thread types are compatible. Numbered connections range from NC10 to NC77 with varying spacing and corresponding inside and outside diameters. Again, it is best to check with the drill pipe joint manufacturer to see if the NC and thread types are compatible.

Union Steel Industry can supply drill pipes with versatile connections, if you have any further requirement, please contact at:sales@union-steels.com