Drill Pipes and Drill collars
Drill Pipes
Drill pipes are metal parts to which the drilling tool is attached. They are they part of the drilling rig which drives the tool head through the turntable.
The drill pipes are designed with a tool joint located at the top and bottom of the pipe with an interior thread (male or female). The pipes are assembled to each other using this thread.
Tool joints are thicker components to which the tightening wrench can be applied.
They allow the drill pipes to be attached without deformation under the force applied by the tightening wrench.
All pipes sold by the MatFor company have a Certificate of Inspection which shows their technical properties, size, and if they have any cracks, since most drill pipes are reused. The Inspection Certificates also report the life of the drill pipe: has it encountered a problem in the ground? In what order? The nature of the problems that have arisen will help to determine the future uses for which the pipe may be reused.
Drill pipes may be new pipes (from the factory, never before used), or Premium (used, inspected and graded by level of use: Grade 1, Grade 2, etc.).
Drill pipes are classified by higher or lower grade of steel and are 2-3/8" to 6-5/8" diameter.
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Drill Colars
Drill collars are used to add weight to the tool, as ballast, while keeping the drill pipes under tension. This system prevents the pipe from "burning" (twisting), by exerting too much pressure on it. The drill collars are very thick pipes. Given their rigidity, the drill collars help to keep the borehole vertical. They do not forcibly prevent an angular deviation during drilling but rapidly forestall it.
To prevent a lower drill collar from burning and for optimal usage in straight drilling, 3 different methods can be used:
- Drill collars can be selected that are as wide as possible and installed in the lower section, leaving enough space between the collars and the borehole walls to permit debris and drilling mud to pass.
- A stabilizer or reamer may be installed in the drill collar assembly.
- Blades can be welded to the drill collars so that their diameter is nearly the same as the borehole diameter.
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