Heavy weight drill pipes have thicker walls than standard drill pipes, and accordingly, almost twice that weight. At the same time heavy weight drill pipes have greater flexibility than Drill collars. These pipes can be installed in place of Drill collars, if the load on the hook becomes excessive.

Owing to its heavy weight these drill pipes provide higher footage rate as well as stability of Drill collars. However, they have more flexibility than Drill collars and have greater resistance to fatigue failure than standard drill pipes.

Heavy weight drill pipes should be used: 

  • in any transition zones of a drill string (e.g. the transition area between drill collars and drill pipes  from more rigid to the more flexible drill string elements); 

  • in highly deviated wells; 

  • when the drill string is operated in compressional environment. 

Standard: API Spec 7-1 

Material: AISI4145H Steel

Type: one-piece, with tool-joint

STANDARD HWDP
Nominal size* 2-7/8 3-1/2 4 4-1/2 5 5-1/2 6-5/8
Pipe Specifications
ID (inches) 2-1/8 2-1/4 2-9/16 2-13/16 3 4 4
WT (inches) 0,375 0,625 0,719 0,844 1,000 0,750 1,313
Section area (sq.inches) 2,945 5,645 7,409 9,692 12,566 11,192 21,905
Center upset diameter (inches) 3-3/8 4 4-1/2 5 5-1/2 6 7-1/8
Yield point (lbs/sq.inches) 55 000 55 000 55 000 55 000 55 000 55 000 55 000
Tensile yield point (lbs) 161 975 310 478 407 502 533 043 691 150 615 560 1 204 775
Torsion yield point (ft-lbs) 8 657 18 461 27 636 40 098 56 496 62 223 130 924
Pipe Joint Specifications
Pipe joint 2-7/8 SL-H90 NC38 NC40 NC46 NC50 5-1/2 FH 6-5/8 IF
Size   3-1/2 IF 4 FH 4 IF 4-1/2 IF    
OD (inches) 3-3/4 4-3/4 5-1/4 6-1/4 6-1/2 7-1/4 8
ID (inches) 2-1/8 2-1/4 2-9/16 2-13/16 3 4 4
Yield point (lbs/sq.inch) 110 000 110 000 110 000 110 000 110 000 100 000 100 000
Tensile yield point (lbs) 346 381 724 990 768 402 1 055 214 1 298 461 1 054 835 1 913 872
Torsion yield point (ft-lbs) 9 95 17 576 25 446 39 976 52 237 47 043 73 214
Make-up Stress (lbs/sq.inch) 56 200 62 500 62 500 62 500 62 500 62 500 62 500
MUT (ft-lbs) 5 084 9 986 14 458 22 714 29 680 29 402 45 759
Technical Specifications
Linear Weight (per ft.) 12,5 23,7 29,9 40,8 50,0 46,7 83,4
30’ Pipe Weight 376 720 912 1244 1516 1424 2501
Displacement Volume (gallon/DP section) 5,87 11,01 13,92 19,02 23,18 29,32 38,25
Displacement Volume (barrel/DP section) 0,140 0,262 0,332 0,453 0,552 0,698 0,91
Capacity (gallon/DP section) 5,62 6,2 8,04 9,264 11,025 19,6 30,59
Capacity (barrel/DP section) 0,134 0,147 0,191 0,22 0,262 0,466 0,728
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