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Classification of drill pipe
Feb 12, 2019
MF Drill Rod 4660 Length For Bench Drilling.jpg

The drill pipe is divided into three types: a square drill pipe, a drill pipe and a weighted drill pipe. The connection sequence is kelly (1) + drill pipe (n, determined by well depth) + weighted drill pipe (n, determined by the drill combination design).

Square drill pipe

The kelly is located at the uppermost end of the drill string and is available in both square and hexagonal [3].


1 When drilling, the kelly cooperates with the center of filling and the center of the turntable to transmit the ground rotation torque to the drill pipe to drive the drill string and the drill bit to rotate;

2 withstand the full weight of the drill string;

3 channels for drilling fluid circulation.


The kelly consists of upper and lower joints and a tubular body. The pipe body part is a square or hexagonal structure (the oil drilling is mostly a square structure); the upper joint is a left-handed female thread (reverse buckle), which is connected with the faucet, and the left-handed female thread prevents the reverse buckle during the rotation; the lower joint It is a right-handed male thread and is connected to the drill pipe. When working, the upper end of the kelly is always above the turntable surface, and the lower part is below the turntable surface.

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