round drill collar
There are different kinds of drill collars,including round drill collar,spiral drill collar,non-magnetic drill collar,square drill collar and so on.Ordinary drill collar is the circular cross section, the center has a water hole,the wall thickness is larger,the nozzle is smaller, the weight of per unit length is greater than the size of drill pipe almost 4- 5 times .The majority of drill collar is thread processing directly on the pipe body , but some of them also use the replaced joint.
(1)Eccentric-weight drill collar is an effective anti-deviation drilling tool,with high drill pressure used in oblique areas,rectifying oblique as well.
(2)When drilling directional wells eccentric-weight drill collar is an effective tool to reduce oblique or straighten the well hole using high drilling pressure.
(3)Eccentric-weight drill collar has the advantages of simple structure,convenient use,connected directly to common drill collar without centralizers,greatly convenient for sinking in,fishing and milling operations.
(4)Eccentric-weight drill collar runs downhole safely,danger of leakage or bit freezing hard to appear.
(5)Pay much attention to avoid mud balling and prevent effect of anti-deviation .
CHEMICAL COMPOSITION
Drill Collar Specification | ||||||||
Thread Type | O.D. | I.D. | Length | Diameter of shoulder guide Angle | Reference bending strength ratio | |||
mm | inch | mm | inch | mm | inch | |||
NC23-31 | 79.4 | 31/8 | 31.8 | 11/4 | 9150 | 30ft | 76.2 | 2.57:1 |
NC26-35(23/8IF) | 88.9 | 31/2 | 38.1 | 11/2 | 82.9 | 2.42:1 | ||
NC31-41(27/8IF) | 104.8 | 41/8 | 50.8 | 2 | 100.4 | 2.43:1 | ||
NC35-47 | 120.7 | 43/4 | 50.8 | 2 | 114.7 | 2.58:1 | ||
NC38-50(31/2IF) | 127 | 5 | 57.2 | 21/4 | 121 | 2.38:1 | ||
NC44-60 | 152.4 | 6 | 57.2 | 21/4 | 9150or9450 | 30ftor31ft | 144.5 | 2.49:1 |
NC44-60 | 152.4 | 6 | 71.4 | 213/16 | 144.5 | 2.84:1 | ||
NC44-62 | 158.8 | 61/4 | 57.2 | 21/4 | 149.2 | 2.91:1 | ||
NC46-62(4IF) | 158.8 | 61/4 | 71.4 | 213/16 | 150 | 2.63:1 | ||
NC46-65(4IF) | 165.1 | 61/2 | 57.2 | 21/4 | 154.8 | 2.76:1 | ||
NC46-65(4IF) | 165.1 | 61/2 | 71.4 | 213/16 | 154.8 | 3.05:1 | ||
NC46-67(4IF) | 171.4 | 63/4 | 57.2 | 21/4 | 159.5 | 3.18:1 | ||
NC50-67(41/2IF) | 171.4 | 63/4 | 71.4 | 213/16 | 159.5 | 2.37:1 | ||
NC50-70(41/2IF) | 177.8 | 7 | 57.2 | 21/4 | 164.7 | 2.54:1 | ||
NC50-70(41/2IF) | 177.8 | 7 | 71.4 | 213/16 | 164.7 | 2.37:1 | ||
NC50-72(41/2IF) | 184.2 | 71/4 | 71.4 | 213/16 | 169.5 | 3.12:1 | ||
NC56-77 | 196.8 | 73/4 | 71.4 | 213/16 | 185.3 | 2.70:1 | ||
NC56-80 | 203.2 | 8 | 71.4 | 213/16 | 190.1 | 3.02:1 | ||
65/8REG | 209.6 | 81/4 | 71.4 | 213/16 | 195.7 | 2.93:1 | ||
NC61-90 | 228.6 | 9 | 71.4 | 213/16 | 212.7 | 3.17:1 | ||
75/8REG | 241.3 | 91/2 | 76.2 | 3 | 223.8 | 2.81:1 | ||
NC70-97 | 247.6 | 93/4 | 76.2 | 3 | 232.6 | 2.57:1 | ||
NC70-100 | 254 | 10 | 76.2 | 3 | 237.3 | 2.81:1 | ||
85/8REG | 279.4 | 11 | 76.2 | 3 | 266.7 | 2.84:1 | ||
Note: 1.Drill collar thread type: NC-Digital IF-Internal flat type REG-Normal type | ||||||||
