Effective Drillstring Weight During Drilling Formula
Effective Drillstring Weight During Drilling calculates effective drillstring weight for drillstring and rig mechanics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (w_s, rho_o, rho_s) 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, w_o equals 81,679.389313 lb.
100000
12
65.5
Inputs
w_s
lbWeight of drillstring material in air
rho_o
ppgMud density
rho_s
ppgDrillstring material density
Outputs
w_o
Effective drillstring weight
w_s
Weight of drillstring material in air
rho_o
Mud density
rho_s
Drillstring material density
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 26.
Source