Drilling EngineeringDrillstring and Rig Mechanics
Maximum Equivalent Derrick Load Formula
Maximum Equivalent Derrick Load calculates maximum equivalent derrick load for drillstring and rig mechanics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (F_h, n) are known and the assumptions behind the cited drillstring and rig mechanics relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, F_de equals 150,000 lb.
F_hlb
100000
ndimensionless
8
Inputs
F_h
lbLoad hoisted
n
dimensionlessLines strung between crown block and traveling block
Outputs
F_de
lb
Maximum equivalent derrick load
F_h
lb
Load hoisted
n
dimensionless
Lines strung between crown block and traveling block
Source and review
reviewed501 Solved Problems and Calculations for Drilling Operations, Robello, S.E. (2015)
Samuel, E. Robello. 501 Solved Problems and Calculations for Drilling Operations, Sigma Quadrant, Houston, Texas, 2015, Page 11.
Source