The drill collar is located in the lower part of the drill column and is the main part of the BHA. The main features are large wall thickness, high gravity, and rigidity. In order to facilitate the start-up and down-drilling, a crane slot and a tile slot can be processed on the outer surface of the internal thread of the drill collar.
drill collars
Types of drill collars
(1)Spiral drill collar has three right-handed spiral grooves machined on the outer cylindrical surface of the round drill collar to reduce the contact area with the good wall and effectively prevent differential pressure from jamming the drill
(2)Non-magnetic drill collar is mainly used for monitoring during oil drilling, and its structure is the same as that of an integral drill collar.
(3) The integral drill collar is a smooth, thick-walled round tube with connection threads machined at both ends.
Role of drill collar
(1) Ensure the necessary pressure strength
(2) To control the slope of the well
(3) To apply drilling pressure to the drill bit
(4) Reduce the vibration, oscillation, and runout of the drill bit, and make the drill bit work smoothly
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