Differential Hydrostatic Pressure Between Cement Annulus and Mud in Casing Formula
Differential Hydrostatic Pressure Between Cement Annulus and Mud in Casing calculates total pressure differential for mud and cementing workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (h_w, h_f, h_l, h_t, w_m, w_l, w_t) are known and the assumptions behind the cited mud and cementing 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, P_d equals 316.992 psi.
10000
80
3000
500
12
13.5
15.8
Inputs
h_w
ftWell Depth
h_f
ftFloat Collar Height Above Shoe
h_l
ftLead Slurry Depth
h_t
ftTail Slurry Depth
w_m
lb/galMud Weight
w_l
lb/galLead Slurry Weight
w_t
lb/galTail Slurry Weight
Outputs
P_a
Total Pressure in Annulus
P_c
Total Pressure in Casing
P_d
Total Pressure Differential
Source and review
reviewedFormulas and Calculations for Drilling, Production and Workover, Lyons, W.C., Carter, T., Lapeyrouse, N.J. (2012)
Lyons, W.C., Carter, T., and Lapeyrouse, N.J. 2012. Formulas and Calculations for Drilling, Production and Workover, 3rd Edition, Gulf Professional Publishing, Page 84.