EOU Clearance Distance for Wellbore Collision Avoidance Formula
EOU Clearance Distance for Wellbore Collision Avoidance calculates ellipse-of-uncertainty clearance distance for directional drilling workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (C_C, R_ref, R_off) are known and the assumptions behind the cited directional drilling 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, E_clear equals 37.801099 ft.
72.80109889280519
20
15
Inputs
C_C
ftCenter-to-Center Distance Between Wells
R_ref
ftReference Well Ellipse-of-Uncertainty Radius
R_off
ftOffset Well Ellipse-of-Uncertainty Radius
Outputs
E_clear
Ellipse-of-Uncertainty Clearance Distance
C_C
Center-to-Center Distance Between Wells
R_ref
Reference Well Ellipse-of-Uncertainty Radius
R_off
Offset Well Ellipse-of-Uncertainty Radius
Source and review
reviewedISCWSA Collision Avoidance Calculations - Current Common Practice; Mansouri et al. 2020 EOU distance definition.
Source