Torque and drag calculator
Field units
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Pick-up, slack-off and rotating hook loads and off-bottom torque for a build-and-hold well. Every equation and assumption is listed under the answer.
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Build-and-hold soft-string
| End of build | 6,900 ft MD | |
| Pick-up hook load | 162.7 klbf | |
| Rotating off-bottom | 108.6 klbf | |
| Slack-off hook load | 51.4 klbf | |
| Off-bottom rotating torque | 8,295 ft·lbf |
- Soft-string model (Johancsik et al. 1984): ΔF = wΔL cosθ ± μN, N = |FΔθ + wΔL sinθ|, ΔM = μNr, 10 ft steps, no azimuth change.
- Uniform pipe, one friction factor, no WOB, no block weight, no tool joints or stiffness. Friction factor is your assumption — calibrate it to a measured hook load.