Non Spiral Drill Collars

Brand Name:ROSCHEN
Certification:API
Model Number:6.750”, 8.75", 9.5"
Minimum Order Quantity:5sets
Place of Origin:China
Price:Negotiate
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Location: Shanghai Shanghai China
Address: 65 EAST XINHUAN ROAD, SHANGHAI, CHINA
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Non-Magnetic Spiral Drill Collars


Non-magnetic drill collars:

NMDCs are generally flush (nonspiral). They are manufactured from high-quality, corrosion-resistant, stainless steel. They are used while running the magnetic survey instruments to be located in a NMDC of sufficient length to allow the measurement of the earth's magnetic field without magnetic interference. Survey instruments are isolated from magnetic disturbance caused by other steel components in the BHA.


Non-magnetic Spiral Drill Collar 6.750” NC50

Specification Tool Joint/Connection Specifications
Nominal OD6 3/4"(6.75")ConnectionNC50Bend Stress Ratio 
Nominal ID2.7/8"(2.875")OD6 3/4" (6.75")ID2 7/8"(2.875")
Material GradeP530Adjusted Weight Average Length31.00 ft
Grain SizeASTMRecommended Make Up Torque Maximum Make Up Torque 
Magnetic Permeability1.001maxSlip RecessN/AElevator RecessN/A
Drift Size3 1/8"(3.125")Fluid Displacement Fluid capacity 
HardbandingNoneInspection CriteriaNS-2Elongation18%
IPCNone 
Chemical PropertiesPhosphorus <0.05%
Sulphur <0.03%
Manufacturing CriteriaAPI Spec7-1
Drill Collar Capacities
Tensile Strength120,000 psi Minimum
827 Mpa
Yield Strength110,000 psi Minimum
758 Mpa
Impact StrengthAbove 60J
Hardness(Brinell)Minimum 285 BHN

Non-magnetic Spiral Drill Collar 8.250” 6 5/8” Reg

Specification Tool Joint/Connection Specifications
Nominal OD8 1/4"(8.25") Connection6 5/8" REGBend Stress Ratio 
Nominal ID2 13/16"(2.8125") OD8 1/4" (8.25")ID2 13/16" (2.8125")
Material GradeP530 Adjusted Weight Average Length31.00 ft
Grain SizeASTM Recommended Make Up Torque Maximum Make Up Torque 
Magnetic Permeability1.001max Slip RecessN/AElevator RecessN/A
Drift Size2 11/16"(2.6875") Fluid Displacement Fluid capacity 
HardbandingNone Inspection CriteriaNS-2Elongation20%
IPCNone 
Chemical PropertiesPhosphorus <0.05%
Sulphur <0.03%
Manufacturing CriteriaAPI Spec7-1
Drill Collar Capacities
Tensile Strength100,000 psi Minimum
689 Mpa
Yield Strength110,000 psi Minimum
758 Mpa
Impact StrengthAbove 60J
Hardness(Brinell)Minimum 285 BHN

Non-magnetic Spiral Drill Collar 9.500” 7 5/8” Reg

Specification Tool Joint/Connection Specifications
Nominal OD9 1/2"(9.5") Connection7 5/8" REGBend Stress Ratio 
Nominal ID3"(3") OD9 1/2" (9.5")ID3" (3")
Material GradeP530 Adjusted Weight Average Length31.00 ft
Grain SizeASTM Recommended Make Up Torque Maximum Make Up Torque 
Magnetic Permeability1.001max Slip RecessN/AElevator RecessN/A
Drift Size2 7/8"(2.875") Fluid Displacement Fluid capacity 
HardbandingNone Inspection CriteriaNS-2Elongation20%
IPCNone 
Chemical PropertiesPhosphorus <0.05%
Sulphur <0.03%
Manufacturing CriteriaAPI Spec7-1
Drill Collar Capacities
Tensile Strength110,000 psi Minimum
758 Mpa
Yield Strength100,000 psi Minimum
689 Mpa
Impact StrengthAbove 60J
Hardness(Brinell)Minimum 285 BHN

Drill Collar Classification


Drill collars can be simply put into three categories according to their structure and material, namely the slick drill collar, the spiral grooved drill collar and the non-magnetic drill collar.

The slick drill collar is normally a smooth thicked-wall tube, with a thickness in the range of 38 to 53, about 4 to 8 times of that of the drill pipes. It is machined into a uniform cylindrical shape and made up of plain alloy steel.


The spiral grooved drill collar is also machined from plain alloy steel, but it is normally lighter by 4 to 6 percent than the slicker drill collar. This kind of drill collar is widely used nowadays because the special spiral design largely hold back of the possibility of sticking accidents by reducing the area of contact between the wall and the collar.


The non-magnetic drill collar is manufactured from the non-magnetic alloy steel. As the magnetic measuring instruments can sense the geomagnetic field when measuring the direction of the borehole, the instruments must be kept working in a non-magnetic environment. However, in drilling process, the magnetic rigs always affect the accuracy of the measuring instrument. Therefore, the utilization of a non-magnetic drill collar can ensure a more reliable measuring result.


Drill Collars in Drilling Application

Drill collars play a vital role in drilling process. Due to the structural features, drill collars can provide weight for drilling purpose, which is drill collar’s one and foremost specialty. Gravity works on a number of drill collars to offer enough downward force needed to break rocks with the drill bit.

Apart from providing weight on the bit (WOB), drill collars also work as a shock absorber to dampen the vibration and shaking when drilling takes place. In this way, the drilling process can be carried out in a much steadier state.

Thirdly, the presence of the drill collars allows the pipelines to stay in the tensile state, while guarantees the rigidity of the drill string under great compression. Thus, the drill efficiency and quality are greatly improved.

In addition to the above applications, drill collars can help to control the direction of the bottom hole assembly, avoiding the problem of hole deviation and enhancing the performance of drilling.


For more information please contact:


Skype: ROSCHEN.TOOL , ROSCHEN_GROUP

WeChat: +86-137 6419 5009 ; +86-135 8585 5390

WhatsApp: +86-137 6419 5009 ; +86-135 8585 5390

Email: roschen@roschen.com ; roschen@roschen.net


Website: http://www.roschen.com ; http://www.roschen.net


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Non Spiral Drill Collars

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