A bar in a drilling tool that is connected and used to transfer power. The common components of the drill string are: drill bit, drill collar, drill pipe, stabilizer, special joint and kelly pipe. The basic functions of the drill string are :(1) to pull off the bit; (2) Apply weight on bit; (3) Transfer power; (4) Conveying drilling fluid; (5) Special operations: squeezing cement, dealing with underground accidents, etc.
API standard E75 to S135 steel grades from 2 3/8 “to 6 5/8” outside diameter series of oil drill pipe as well as high torsional resistance double shoulder joint drill pipe and special steel grade BNK C95S drill pipe for sulfur Wells. It is mainly applied to the construction of deep Wells, horizontal Wells and extended reach Wells in the process of oil and gas exploration and development.
Drill pipe is steel pipe with indulge grain on the tail, which is used to connect the surface equipment of the drill rig to the drilling and grinding equipment or bottom hole device located at the bottom of the drill. The purpose of the drill pipe is to transport drilling mud to the bit and to raise, lower, or rotate the bottom hole device with the bit. The drill pipe must be able to withstand tremendous internal and external pressure, distortion, bending and vibration. In the process of oil and gas extraction and refining, drill pipe can be used many times.
The clean pipe and raw steel pipe are made into drill pipe after several processing steps. First of all, through the processing of the steel pipe thickening process, the surface of the light pipe is curved inward, and the wall of the steel pipe is thickened. Next, the thread is machined and plated with copper to increase strength. A non-destructive quality control test is then carried out, followed by the welding of the pipe body joint. The tube is then subjected to welding heat treatment and welding final treatment to eliminate welding residual pressure. Before the finished drill pipe is painted and packaged, the finished steel pipe is subjected to a number of other tests, including hardness testing, pressure testing and non-destructive testing.
The length of the drill pipe is usually about nine meters.