# Maximum Initial Shut-In Casing Pressure (MISICP)

Maximum Initial Shut-In Casing Pressure (MISICP) or Maximum allowable shut in casing pressure is the initial shut-in casing pressure that will exceed formation strength at the casing shoe resulting in broken formation at the shoe.

How can we know and calculate the MISICP?

Leak Off Test (LOT) will tell you the maximum pressure which the shoe can withstand before breaking formation at the shoe. The LOT is the combination of surface pressure and hydrostatic pressure therefore you can apply this principle to calculate the MISICP.

The MISICP formula is listed below:

MISICP, psi = (LOT, ppg – Current Mud Weight, ppg) x 0.052 x TVD of shoe, ft

Please see the example demonstrating how to calculate the MISCIP by using the following information:

LOT = 15.0 ppg

Current mud weight = 10.0 ppg

Casing shoe depth = 4526’MD/4200’TVD

MISICP, psi = (15 – 10) x 0.052 x 4200

MISICP = 1,092 psi

Note: Please ensure that you use the TVD for calculating the MISICP.

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### 7 Responses to Maximum Initial Shut-In Casing Pressure (MISICP)

1. milud says:

if the casing pressure exceeds the MAASP while the influx is inside the casing, in this case could i shut in the well or carry on every is ok? please find for me the right answer. thank you.

• You should carry on. Your casing shoe may or may not be broken because the mud sometimes strengthen the shoe.
You need to reduce kill rate in order to reduce overall pressure which will help you.