The structure of the kelly

The kelly consists of upper and lower joints and pipe body parts. The pipe body has two structures of square or hexagonal (most of the oil drillings are of 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 is prevented from being inverted during the rotation process; the lower joint It is a right-hand male thread, which 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.