Functions: Tubular products such as tubing and casing have several functions in drilling equipment. They serve to isolate the drilling from any external contamination (debris, cuttings, fluids, drilling mud). Cement is cast around them to consolidate the walls to prevent collapse and to ensure that evacuated rock does not enter the boreholes. Once the hole is drilled and has reached the desired depth, the tubing provides an avenue for cement to isolate and consolidate the borehole walls.
Tubing and casing also serve to recover drilling products such as water and oil.
Tubing is a small diameter drilling tube. MatFor offers tubing from 1.050" to 4-1/2"
Casing is larger, from 4.5", and as wide as 20".
Drilling usually begins with large diameter casing and ends with smaller tubing.
The size of the tubing is predetermined by the drilling program, depending on the terrain and the drilling sequence.
Other types of tubing
Tubing which isolates the borehole from cuttings (evacuated rock) and which contains drilling fluids during operations are called conductor casing or surface casing. Intermediate casing and production casing both have different roles. The first is optional, and is installed in the wells, inside the surface casing to allow for future drilling operations within the wells. Production casing is used to isolate the casing from the operation system (pump and drill pipes). This casing is cemented into the wellbore, at least in the lower part of the borehole if an intermediate casing is used.Among casings, there are also micropiles, which are only used for foundations. These serve to stabilize the ground and consolidate the cement. They are 60 to 339 mm in diameter and are positioned by other tubes specially designed to carry the micropiles. Micropiles are all identified by a steel grade, the letter corresponding to the chemical composition of the steel and the digit to its elasticity, or elongation capacity. Steels such as K55 to S135 are used in oil and water drilling, with the elongation capacity from the smallest to the most significant.