A Comprehensive Overview of Drill Collars and Their Applications

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DIC Oil Tools is one of the leading Suppliers of the highest-quality products for the Oil & Gas Industry. All products are tested numerous times under technical guidance and constructed from the highest-quality materials. We can also provide custom-designed equipment as per customer requirements.

We supply a full range of high-quality Drill Collar. DIC Oil Tools is Brand by a Dedicated Impex Company.


Drill collars are one of the components of a drill string. Drills for collars are meant to provide weight for drilling purposes. Drill collars are thick-walled tube like pieces made from solid steel bars, although they are often made from plain carbon steel or non-magnetic alloys of copper and steel or other premium alloys that are non-magnetic. Drill collars consist of solid steel bars that are drilled from one end to the other to provide a path for pumping drilling fluid through the collar.

Collars available for drilling have an outside diameter that is made of steel and may be slightly machine-perfected to ensure roundness. Drill collars are sometimes completed with the help of spiral collars or helical shaped grooves. Drill threaded collars have connections that are male or female on one end and female on the other. These are cut into a multiple collar that can be adjusted with a screw with other downhole tools. The drill helps create a bottom hole assembly or BHA.

Purpose of Drill Collar:

(1) Add weight to the drill bit – The heavy weight of the collar provides “weight on the bit” to increase penetration rate and drilling efficiency, especially in hard rock. The higher the load the more effective the crushing and fracture formation.

(2) Stiffen the drill string – Thick walls give the collar high flexural stiffness to resist bending of the pipe. This maintains a good vertical profile and improves directional control.

(3) Prevent Buckling- The danger of the drill string helical buckling during operations is decreased by the collars’ increased bulk.

(4) Stabilize the bottom hole assembly – collars stabilize the bit and bottom of the drill string to maintain the directional trajectory.

(5) Absorb Drilling loads – Collars resist failure when subjected to axial, bending, and torsional loads during drilling.

(6) Resist Drill String Twisting – Rigidity resists pipe twisting and maintains smooth transfer of rotary power to the bit.

Drilling Collar Types:

Slick type

The thin type is the most common which is used from the beginning. It has no features. Its main function is to add weight to the bit and increase stability while drilling.

Spiral drill collar

When drilling through certain formations, large-diameter Drill collars can get stuck against the borehole. This is likely to occur when the formation is highly porous, using a large excess of mud pressure, and the wellbore deviates. One way to prevent this problem is to reduce the contact area of the collar against the wellbore. We can cut spiral grooves on the surface of the collar to reduce its surface area.


Material                                                                                                                                                             AISI4145H, 4145H Mod, non-magnetic material
               Standard                                                                                                                                                   API Spec.7-1and NS-1
                    Type                   Slick Drill Collar, Spiral Drill Collar, Short Drill Collar
Special FeatureThreads Cold Rolled; Pin Relief Groove and Box Bore Back; Elevator and Slip Recess; Hard banding

To learn more, or get a high-quality Drill Collar from DIC Oil Tools, Contact us at: info@dic-oiltools.com.

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