Enter the hydrostatic pressure of the mud in the annulus (psi), the hydrostatic pressure of the influx (psi), and the shut-in casing pressure (psi) into the Formation Pressure Calculator. The calculator will evaluate the Formation Pressure. 

Formation Pressure Formula

The following formula is used to calculate the Formation Pressure. 

FP = HSPM + HSPI + SICP

Variables:

  • FP is the Formation Pressure (psi)
  • HSPM is the hydrostatic pressure of the mud in the annulus (psi) 
  • HSPI is the hydrostatic pressure of the influx (psi) 
  • SICP is the shut-in casing pressure (psi) 

How to Calculate Formation Pressure?

The following steps outline how to calculate the Formation Pressure.


  1. First, determine the hydrostatic pressure of the mud in the annulus (psi).
  2. Next, determine the hydrostatic pressure of the influx (psi). 
  3. Next, determine the shut-in casing pressure (psi). 
  4. Next, gather the formula from above = FP = HSPM + HSPI + SICP.
  5. Finally, calculate the Formation Pressure.
  6. After inserting the variables and calculating the result, check your answer with the calculator above. 

Example Problem:

Use the following variables as an example problem to test your knowledge.

hydrostatic pressure of the mud in the annulus (psi) = 100

hydrostatic pressure of the influx (psi) = 230

shut-in casing pressure (psi) = 10

FP = HSPM + HSPI + SICP =  ?