Differences In Steel Grades Between Drill Pipe And Oil Casing

Drill pipe and oil casing are two different types of steel pipe used in oil and gas exploration and production, with different uses and performance requirements. Oil casing is a steel pipe used to support the well wall of oil and gas wells to ensure the normal operation of the entire oil well after drilling and completion. Oil drill pipe is a steel pipe with a thread at the end, used to connect the surface equipment of the drilling rig to the downhole drilling and grinding equipment or downhole equipment. The following are the steel grade (steel material) differences between them.

Casing:

Oil casing can be divided into different steel grades according to the strength of the steel itself, namely J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. Casing end processing forms: short round thread, long round thread, partial trapezoidal thread, special buckle type, etc. There are different steel grades for different well conditions and depths. In corrosive environments, the casing itself is also required to be corrosion-resistant. In places with complex geological conditions, casings are also required to have collapse resistance. It is mainly used to support the well wall during the drilling process and after well completion to ensure the progress of the drilling process and the normal operation of the entire well after completion.

Drill Pipe:

Petroleum drill pipe steel grade refers to the grade of drill pipe steel, which is determined by the yield strength of the drill pipe steel. API (American Petroleum Institute) divides drill pipe steel grades into five grades: D, E, 95(X), 105(G), and 135(S). The higher the drill pipe steel grade, the greater the yield strength of the pipe and the greater the various strengths of the drill pipe. In the design of drill string strength, it is recommended to increase the strength of the drill string by increasing the steel grade rather than increasing the wall thickness.