What Is The Difference Between Drill Pipe And Drill Collar?

Both of drill pipe and drill collar are significant oilfield tubular goods. But what is the difference between drill pipe and drill collar? Continue reading to learn more.

Drill Pipe:

A drill pipe is a long hollow steel pipe that is used to rotate the drill bit and circulate drilling fluid in the well. It is typically made of alloy steel and has a threaded connection at each end, called a tool joint, that allows it to be screwed together with other drill pipe sections or with other drill stem components, such as a drill collar.

Drill Collar:

A drill collar is a thick-walled, heavy, and short section of drill pipe that is added to the bottom of the drill string to provide weight on the bit. It is typically made of high-strength steel, such as alloy steel or tungsten carbide. Drill collars are used to help keep the drill string straight and to provide a means of transmitting drilling torque to the bit.

The drill collar is located in the lower part of the drill string and is the main part of the lower drill tool assembly. Its main feature is that the wall thickness is relatively large (generally 38-53mm, which is equivalent to 4-6 times the wall thickness of the drill pipe), and it has greater gravity and rigidity. Drill collars are generally divided into three types: spiral drill collars, non-magnetic drill collars, and integral drill collars.

Drill collars are generally divided into three types: spiral drill collars, non-magnetic drill collars, and integral drill collars.

Difference Between Drill Pipe And Drill Collar:

The drill collar is thicker than the drill pipe, and the weight per unit length is heavier. The lower part of the drill collar is connected with the drill bit, and the upper part is connected with the drill pipe. The functions are similar. The drill pipe mainly transmits motion and power. The drill collar is stronger than the drill pipe and directly drives the drill bit to work.