STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

586 Drilling and Well Completions
C AS E "A" C A S E "E" C A S E "C"
Sheaves
S =6
L: Load; S=No. of Sheaves; N = No. of Rope Ports Supporting Load
FAST LINE TENSION = FAST LINE FACTOR X LOAD
1 2 3 4 5 6 7 8 9 10 11 le 13
Plain Bearing Sheaves
Roller Bearing Sheaves
= 109. K = 1.04.
Efficiency Fast Line Factor
e
Efficiency Fast Line Factor
case case case case CMe cw cw case case case case case
N A B C A B C A B C A B C
2 380 .807 .740 368 .620 .675 943 ,907 .E72 .530 .551 ,574
3 844 .774 .710 .395 .431 .469 .E5 .889 .855 .360 ,375 990
4 810 .743 .682 .309 836 .367 .908 373 .839 275 586 298
5 .778 .714 ,655 357 .280 805 890 356 .823 .225 234 243
6 .748 .686 .629 .223 .243 265 874 ffl0 .808 .191 .198 206
7 .719 360 .605 .I99 216 236 ,857 .824 ,793 .167 .173 .I80
8 .692 ,635 ,582 .181 ,197 215 .842 ,809 ,778 .l48 .154 .I61
9 .666 ,611 ,561 ,167 ,182 .198 .826 ,794 ,764 .135 ,140 ,145
10 ,642 .589 540 ,156 .170 .185 311 ,780 ,750 ,123 ,128 ,133
11 ,619 .568 ,521 ,147 .160 .173 .796 ,766 .736 .114 ,119 .124
12 ,597 .547 .502 ,140 .I52 .166 .782 ,752 .723 ,106 .I11 .115
13 576 .528 .485 .I33 .145 ,159 .768 ,739 ,710 .1W ,104 .IO8
14 556 ,510 ,468 .128 .140 .153 .755 ,725 ,698 ,095 .D99 .I02
15 ,537 ,493 .452 ,124 .135 .147 ,741 .713 ,685 .OW ,094 .OS7
I
EFFICIENCY = A Fast Line Factor =
K'N (K-1) N x EFFICIENCY
NOTE The above canes apply aIw where the rope is dead ended at the lower or traveling block or
demck floor after passinp over a dead sheave in the crown.
'In h tables the I( factor for sheave friction iu 1.09 for plain bearinna and 1.M for mller bearinna.
O W K factors cam bc u d if rsammmded by r(lc equipment manufacturer.
Figure 4-68. Efficiency of wire-rope reeving for multiple sheave blocks,
Cases A, B, and C [ll].
The following precautions should be observed to prevent premature wire
breakage in drilling lines.
1. Cable-tool drilling lines. Movement of wire rope against metallic parts can
accelerate wear. This can also create sufficient heat to form martensite,
causing embrittlement of wire and early wire rope removal. Such also can
be formed by friction against the casing or hard rock formation.