Standard: API Spec 7
Material: AISI 4145H Alloy Steel or Non-magnetic material
Specification: OD: 3 1/8”-11”
Length: 10’-32’
Usage: The Drill Collar is used between the drill pipe and the bit in the drill stem. It is used to put weight on the bit so that the bit can drill.
Description:
Slick Drill Collars
Drill collars are made of AISI 4145 H or 4145 H modified alloy steel, which are trepanned and drifted to API Spec. 7. Full-length heat-treatment processes ensure that mechanical properties meet or exceed API Spec. 7 requirements. A hardness range of 285-341 Brinell Hardness and Charpy “V” notch minimum impact strength of 40ft-lb at 70F are guaranteed one inch below the surface.
Spiral Drill Collars
We manufactures not only slick Drill Collars, but also spiral Drill Collars with Slip, Elevator recesses and hardbanding. Our drill collars are available in lengths from 10 to 32 feet and outside diameter from 3-1/8" to 11".
Spiral drill collars are complete product line. Spiral grooves let mud circulate freely around the drill collar to equalize pressure and prevent a seal from forming. The reduces the occurrence of differential sticking without spiral.
Spiral collars are wide used because of their maintenance features. The special grooves decrease the volume of the contact between the well side and the pipe, it leads to the decrease of the “tack” of the pipe and to turning of the drill pipe string.
The weight of round drill collars will be reduced approximately 4-6% by spiral conversion.
Non-magnetic Drill Collars
Materials of the Non-magnetic drill collars are from chrome manganese, low carbon alloy obtained by combining a proprietary chemical analysis and a rotary hammer process. The material is resistant to stress corrosion cracking, with high machine ability and no tendency to galling.
The non-magnetic drill collar exhibit the mechanical properties indicated below along their entire length. The table is derived from test samples of steel taken from a point 1” below the surface.
Magnetic permeability (when MPS=1105 /4 Nm)
Relative max: 1.010 average: Ur≥1.005
Magnetic field gradient (hot spots)
Max: B 0.05micro tesla/100mm
With excellent lower Magnetic permeability, high strength of mechanical properties and outstanding resistant to stress corrosion cracking and no tendency to galling.
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Drill Collar Specification |
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|
Style of Connection |
OD |
ID |
Lmm |
Shoulder bevel edge Diameter |
Bending Strength Ratio |
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|
mm |
in |
mm |
in |
DF(mm) |
|||
|
NC23-31 |
79.4 |
3 1/8 |
31.8 |
1 1/4 |
9150 |
76.2 |
2.57:1 |
|
NC26-35(2 3/8IF) |
88.9 |
3 1/2 |
38.1 |
1 1/2 |
9150 |
82.9 |
2.42:1 |
|
NC31-41(2 7/8IF) |
104.8 |
4 1/8 |
50.8 |
2 |
9150 |
100.4 |
2.43:1 |
|
NC35-47 |
120.7 |
4 3/4 |
50.8 |
2 |
9150 |
114.7 |
2.58:1 |
|
NC3850(3 1/2IF) |
127 |
5 |
57.2 |
2 1/4 |
9150 |
121 |
2.38:1 |
|
NC44-60 |
152.4 |
6 |
57.2 |
2 1/4 |
9150or9450 |
144.5 |
2.49:1 |
|
NC44-62 |
158.8 |
6 1/4 |
57.2 |
2 1/4 |
9150or9450 |
149.2 |
2.91:1 |
|
NC46-62(4IF) |
158.8 |
6 1/4 |
71.4 |
2 13/16 |
9150or9450 |
150 |
2.63:1 |
|
NC46-65(4IF) |
165.1 |
6 1/2 |
57.2 |
2 1/4 |
9150or9450 |
154.8 |
2.76:1 |
|
NC46-65(4IF) |
165.1 |
6 1/2 |
71.4 |
2 13/16 |
9150or9450 |
154.8 |
3.05:1 |
|
NC46-67(4IF) |
171.4 |
6 3/4 |
57.2 |
2 1/4 |
9150or9450 |
159.5 |
3.18:1 |
|
NC50-67(4 1/2IF) |
171.4 |
6 3/4 |
71.4 |
2 13/16 |
9150or9450 |
159.5 |
2.37:1 |
|
NC50-70(4 1/2IF) |
177.8 |
7 |
57.2 |
2 1/4 |
9150or9450 |
164.7 |
2.54:1 |
|
NC50-70(4 1/2IF) |
177.8 |
7 |
71.4 |
2 13/16 |
9150or9450 |
164.7 |
2.73:1 |
|
NC50-72(4 1/2IF) |
184.2 |
7 1/4 |
71.4 |
2 13/16 |
9150or9450 |
169.5 |
3.12:1 |
|
NC50-77 |
196.8 |
7 3/4 |
71.4 |
2 13/16 |
9150or9450 |
185.3 |
2.70:1 |
|
NC50-80 |
203.2 |
8 |
71.4 |
2 13/16 |
9150or9450 |
190.1 |
3.02:1 |
|
6 5/8REG |
209.6 |
8 1/4 |
71.4 |
2 13/16 |
9150or9450 |
195.7 |
2.93:1 |
|
NC61-90 |
228.6 |
9 |
71.4 |
2 13/16 |
9150or9450 |
212.7 |
3.17:1 |
|
7 5/8REG |
241.3 |
9 1/2 |
76.2 |
3 |
9150or9450 |
223.8 |
2.81:1 |
|
NC70-97 |
247.6 |
9 3/4 |
76.2 |
3 |
9150or9450 |
232.6 |
2.57:1 |
|
NC70-100 |
254 |
10 |
76.2 |
3 |
9150or9450 |
237.3 |
2.81:1 |
|
8 5/8REG |
279.4 |
11 |
76.2 |
3 |
9150or9450 |
266.7 |
2.84:1 |
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Mechanical Property of Drill Collar |
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|
OD |
Yield Strength |
Tensile Strength |
Elongation |
Brinell Hardness HB |
Charpy |
|
|
mm |
in inch |
σ 0.2 Mpa |
σ b Mpa |
4% |
AKVJ |
|
|
79.4-171.4 |
3 1/8-6 3/4 |
≥758 |
≥965 |
≥13 |
285-341 |
≥54 |
|
177.8-279.4 |
7-11 |
≥689 |
≥930 |
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Stress Relief Groove for Thread Connection |
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|
Style of Connection |
Length between Inner Thread Shoulder and the last Dens |
Diameter of Inner Thread |
Taper of the Hole nest to inner Thread |
Outer Thread Diameter |
Length between alternative Inner Thread Shoulder and Stress Relief Groove |
|
±1.59mm |
Dcb+0.40,-0 |
±20.83 |
DRG+0 -0.79 |
LRG +0 -3.18 |
|
|
mm |
mm/m |
mm |
mm |
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|
NC35 |
82.6 |
82.15 |
166.67 |
82.15 |
85.73 |
|
NC38(3 1/2IF) |
88.9 |
88.11 |
166.67 |
89.3 |
92.08 |
|
NC44 |
101.6 |
101.6 |
166.67 |
106.36 |
104.78 |
|
NC46(4IF) |
101.6 |
106.76 |
166.67 |
109.93 |
104.78 |
|
NC50(4 1/2IF) |
101.6 |
117.48 |
166.67 |
120.65 |
104.78 |
|
NC56 |
114.3 |
121.84 |
250 |
134.14 |
117.48 |
|
NC61 |
127 |
132.95 |
250 |
149.25 |
130.18 |
|
NC70 |
139.7 |
152 |
250 |
171.05 |
142.88 |
|
6 5/8REG |
114.3 |
134.14 |
166.67 |
137.72 |
117.48 |
|
7 5/8REG |
120.7 |
133.35 |
250 |
162.72 |
123.83 |
|
8 5/8REG |
123.8 |
149.25 |
250 |
184.94 |
127 |
|
Note: The connection of NC23、26、31 and 2 3/8IF are without stress relief groove mould for their thin wall. |
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