Drill Collar and Spiral Drill collar

Drill collar is mainly used to provide bit weight to drill bit so that drill pipe is in tension. Especially drill collar can keep drill bit centralized and hole track by large rigidity. Spiral drill collar is used to reduce contact area with hole so as to avoid efficient bit stricking from differential pressure. Our drill collars are manufactured as per API spec. 7.

The Spiral Drill Collar of Lake is made from AISI 4145H modified alloy steel, and completely meets the requirement of API Spec 7-1 and SY/T5144 Standard. It is a kind of drill collar which adds three dextrogyrate spiral groove on the outer circle of ordinary drill collar when processing, and the purpose is to reduce the area of contact and friction with the well wall, which can effectively prevent the pressure sticking. The single weight of the spiral drill collar is round about 4% lighter than the ordinary drill collar with the same specification, and the shape and thread of the both ends are the same with the drill collar.

Materials:
Drill collars are manufactured from AISI 4145H modified steel, and are supplied in the "as rolled" surface finish condition. Alternative surface finishes are available.

Trepanning and Heat Treatment:

Drill collars are trepanned and drifted to API Spec 7-1. Full-length heat-treatment processes ensure that mechanical properties meet or exceed API Spec 7-1 requirements. A hardness range of 285-341, Brinell hardness and Charpy "V" notch minimum impact strength of 40 ft-lb at 70 F are guaranteed one inch below the surface.

Trace Ability:
Drill collar material and process trace ability are maintained from receipt of the mill's certified raw material to completion of manufacturing. Serial numbers are die stamped on bar bodies.

Rigid Inspection Procedures:
We inspect all our drill collars to ensure compliance with API SPEC 7-1 standards. These inspections include visual dimensional checks as well as ultrasonic inspections over the entire body of the drill collar.

Cold Rolling:
Drill collar thread roots, as well as elevator recess upper radius, are cold-rolled. Cold rolling creates a compressive recess upper radius stress condition that increases fatigue life by minimizing crack initiation.

Phosphate-coated or Copper Plating:
All connections are phosphate-coated or copper plated to improve resistance to corrosion.

Slip Groove, Elevator Groove and Size:
Saigao offers optional slip and elevator recesses to improve handling efficiency and safety. Unless otherwise specified, slip and elevator recesses are machined in compliance with API spec 7-1 guidelines.

Features of Drill Collar and Spiral Drill collar:
Eccentric-weight drill collar is an effective anti-deviation drilling tool,with high drill pressure used in oblique areas,rectifying oblique as well.

When drilling directional wells eccentric-weight drill collar is an effective tool to reduce oblique or straighten the well hole using high drilling pressure.

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.

Eccentric-weight drill collar runs downhole safely,danger of leakage or bit freezing hard to appear.

Technical Spiral Drill Collars Specifications and Spiral Drill collar:
Drill collar thread type OD ID Length (mm)

NC23-31 mm in mm in

NC26-35 ( 23/8 ″ IF ) 79.4 3 1/8 31.8 11月4日 9150

NC31- 41(27/8 ″ IF) 88.9 31/2 38.1 11月2日 9150

NC35-47 104.8 Aug-41 50.8 2 9150

NC38-50(31/2 ″ IF) 120.7 Apr-43 50.8 2 9150

NC44-60 127 5 57.2 4月21日 9150

NC44-60 152.4 6 57.2 4月21日 9150 (or) 9450

NC44-62 152.4 6 71.4 2 13/16 9150 (or) 9450

NC46-62(4 ″ IF) 158.8 Apr-61 57.2 4月21日 9150 (or) 9450

NC46-65(4 ″ IF) 158.8 Apr-61 71.4 2 13/16 9150 (or) 9450

NC46-67(4 ″ IF) 165.1 Feb-61 57.2 2 13/16 9150 (or) 9450

N50-67(4 1/2 ″ IF) 165.1 Feb-61 71.4 2 13/16 9150 (or) 9450

NC50-70(4 1/2 ″ IF) 171.4 Apr-63 57.2 2 13/16 9150 (or) 9450

NC50-70(4 1/2 ″ IF) 171.4 Apr-63 71.4 2 13/16 9150 (or) 9450

NC50-72(4 1/2 ″ IF) 177.8 7 57.2 2 1/4 9150 (or) 9450

NC50-70(4 1/2 ″ IF) 177.8 7 71.4 2 13/16 9150 (or) 9450

NC50-72(4 1/2 ″ IF) 184.2 Apr-71 71.4 2 13/16 9150 (or) 9450

NC56-77 196.8 Apr-73 71.4 2 13/16 9150 (or) 9450

NC56-80 203.2 8 71.4 2 13/16 9150 (or) 9450

6 5/8 ″ REG 209.6 Apr-81 71.4 2 13/16 9150 (or) 9450

NC61-90 228.6 9 71.4 2 13/16 9150 (or) 9450

7 5/8 ″ REG 241.3 9 1/2 76.2 3 9150 (or) 9450

NC70-97 247.6 Apr-93 76.2 3 9150 (or) 9450

NC70-100 254 10 76.2 3 9150 (or) 9450

8 5/8 ″ REG 279.4 11 76.2 3 9150 (or) 9450


Saigao Group is a professional spiral drill collar manufacturers, we provide oilfield cementing tools, circulating swage, pumping unit parts, ditch magnet drilling and etc. Want to know more? Please contact us.