Detailed Drilling Cost per Foot Formula
Detailed Drilling Cost per Foot calculates cost of drilling per foot for drilling operations and economics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (C_b, C_to, C_m, T_d, T_t, T_c, C_r, C_s, C_tr, F) are known and the assumptions behind the cited drilling operations and economics 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, C_d equals 71.3 $/ft.
50000
10000
15000
40
8
4
1000
200
100
50
Inputs
C_b
$Bit cost
C_to
$Tool cost
C_m
$Mud cost
T_d
hDrilling time
T_t
hTrip time
T_c
hConnection time and extras
C_r
$/hRig rate
C_s
$/hSupport rate
C_tr
$/hTool rental rate
F
ft/hAverage footage drilled per hour
Outputs
C_d
Cost of drilling per foot
C_b
Bit cost
C_r
Rig rate
F
Average footage drilled per hour
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 468.