STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

610 Drilling and Well Completions
Service Goal. A goal for line service in terms of ton-miles between cutoffs
should be selected. This value can initially be determined from Figures 4-84 and
4-85 and later adjusted in accordance with experience. Figure 4-86 shows a
graphical method of determining optimum cutoff frequency.
Variations in Line Service. Ton-miles of service will vary with the type and
condition of equipment used, drilling conditions encountered, and the skill used
20 22
24
:* I6 I8
20
I2
8
5
3
Explanation:
To determine (approximately) the desirable ton-miles before the first cutoff
on a new line, draw a vertical line from the derrick height to the wireline
size used. Project this line horizontally to the ton-mile figure given for the
type of drilling encountered in the area. Subsequent cutoffs should be
made at 100 ton-miles less than those indicated for 1Mn. and smaller
lines, and at 200 ton-miles less than 1%-in. and l%-in. lines.
Figure 4-84. Ton-mile derrick height and line-size relationships [l l].*
"The values for ton-miles before cutoff, as given in Figure 4-84 were calculated for improved plow
steel with an independent wire-rope core and operating at a design factor of 5. When a design
factor other than 5 is used, these values should be modified in accordance with Figure 4-85.
The values given in Figure 4-84 are intended to serve as a guide for the selection of initial
ton-mile values as explained in Par. 'Service Goal." These values are conservative, and are
applicable to all typical constructions of wire rope as recommended for the rotary drilling lines
shown in Table 4-9.