Drilling EngineeringWell Control
Final Circulating Pressure Formula
Final circulating pressure estimates circulating pressure after kill-weight mud reaches the bit at the planned kill rate.
How engineers use this formula
Use it with initial circulating pressure to build a well-control pressure schedule during a kill operation.
Assumptions
- Slow circulating pressure is measured at the kill rate.
- Mud weights are in the same unit system.
- Pump speed and hydraulics remain comparable during the schedule.
Limitations
- Does not model dynamic choke response, gas expansion, or changing annular friction.
- Must be checked against the approved well-control method.
Common mistakes
- Using ICP where FCP should be used after kill mud reaches the bit.
- Mixing mud weight units.
- Ignoring planned kill-rate changes.
Default example
Using the default inputs, FCP equals 1,030.754717 psi.
SCRPpsi
900
KWMppg
12.14
OMWppg
10.6
Inputs
SCRP
psiSlow Circulating Rate Pressure
KWM
ppgKill Weight Mud
OMW
ppgOriginal Mud Weight
Outputs
FCP
psi
Final Circulating Pressure
SCRP
psi
Slow Circulating Rate Pressure
KWM
ppg
Kill Weight Mud
OMW
ppg
Original Mud Weight
Source and review
reviewedDrilling Manual. Well Control Formulas & Illustrated Examples.
Source