Drill pipe is divided into three categories: kelly pipe, drill pipe and weighted drill pipe. The connection sequence is kelly pipe (1 piece)+ drill pipe (n pieces, determined by the well depth)+ weighted drill pipe (n pieces, determined by the drill assembly design).

effect

Drill pipe is the basic component of drill string. Its main function is to transfer torque and transport drilling fluid, and by gradually lengthening the drill pipe to deepen the hole. Therefore, drill pipe plays a very important role in oil drilling.

structure

Drill pipe structure Drill pipe is made of seamless steel pipe, the wall thickness is generally 9 ~ 11mm; The pipe body composed of the drill pipe body and the drill pipe joint is welded together with the joint by friction welding.

Square bur

The kelly pipe is located at the upper end of the drill string and is available in two types: square and six.

effect

When drilling, the kelly is matched with the bushing and the turntable bushing to transmit the ground rotating torque to the drill rod to drive the drill string and bit rotation;

Bear the full weight of the drill string;
③ Channel of drilling fluid circulation.

structure

Kelly pipe consists of upper and lower joints and pipe body parts. The pipe body part is of two kinds of structure (most of the oil drilling is of four square structure); The upper connector is the left female thread (reverse button), connected with the faucet, in the rotation process of the left female thread to prevent reverse; The lower joint is right-handed male thread and is connected with 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.

aggravate

The weighted drill pipe is similar to the oil drill pipe, which is also a hollow steel column with a length of about 10 meters. However, the single weight is heavier than the oil drill pipe, the wall thickness is 2 to 3 times that of the drill pipe, and the drill pipe is connected between the drill pipe and the drill pipe, the purpose is to prevent the fatigue damage when the drill string cross-section changes, and it can also replace the role of a part of the drill collar, but its suspension is simple, the operation of tripping is convenient, and the tripping time can be saved.