A drill pipe is a steel pipe threaded at the ends, used to connect surface drilling equipment to the drilling tools or bottom-hole assembly located at the bottom of the well. Its functions include conveying drilling fluid to the bit and-in conjunction with the bit-raising, lowering, or rotating the bottom-hole assembly. Drill pipes must withstand immense internal and external pressures, as well as torsion, bending, and vibration. They can be reused multiple times during oil and gas exploration and extraction operations.
Drill pipes are categorized into three types: kelly pipes, standard drill pipes, and heavy-weight drill pipes. The connection sequence is: kelly pipe (1 joint) + standard drill pipes (n joints, determined by well depth) + heavy-weight drill pipes (n joints, determined by the bottom-hole assembly design). This section details drill pipe classifications, tool joints, specifications, and steel grades and strength ratings.
