Craft and Hawkins Vertical Well Critical Coning Rate Formula
Craft and Hawkins Vertical Well Critical Coning Rate calculates critical oil rate without coning for well performance workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (b, r_w, h, k_o, p_ws, p_wf, mu_o, B_o, r_e) are known and the assumptions behind the cited well performance 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, q_o equals 643.734212 STB/day.
0.5
0.328
50
100
3000
2500
2
1.2
1000
Inputs
b
dimensionlessPenetration Ratio, h_p / h
r_w
ftWellbore Radius
h
ftOil Column Thickness
k_o
mDEffective Oil Permeability
p_ws
psiStatic Well Pressure at Producing Interval Midpoint
p_wf
psiFlowing Well Pressure at Producing Interval Midpoint
mu_o
cPOil Viscosity
B_o
RB/STBOil Formation Volume Factor
r_e
ftDrainage Radius
Outputs
q_o
Critical Oil Rate without Coning
PR
Productivity Ratio
k_o
Effective Oil Permeability
p_ws
Static Well Pressure at Producing Interval Midpoint
p_wf
Flowing Well Pressure at Producing Interval Midpoint
Source and review
reviewedJoshi, S.D. 1991. Horizontal Well Technology, Chapter 8, vertical-well critical-rate correlations.
Source