Sentence examples for drill collars from inspiring English sources

At the bottom end of the drill pipe are extra-heavy sections called drill collars, which serve to concentrate the weight on the rotating bit.

Drill collars.

The number of drill collars used in drill string.

A drill string on a drilling rig is primarily composed of drill pipe, drill collars and drill bit.

The drillstring rotates during drilling, and this may lead to violent lateral vibrations of the drill collars, an effect analogous to the whirling motion of an unbalanced rotor.

In addition to pulling and running drill string, trip time also includes mud circulation before trip out for cleaning the hole and well observation at the bottom hole, casing shoe, and in above of drill collars.

Drill collar length 530 ft Drill collar diameter (OD) 6.25 in.

Unstable drill collar motion can be periodic or chaotic.

So drill collar with double shoulder thread could be an efficient way to solve the fatigue failure problems of drill collar in gas drilling.

However, drill collar failures have often occurred under high weight on bit (WOB) during gas drilling.

The computed results reveal the early drill collar fatigue failures in gas drilling.