Adjusted Maximum Allowable Shut-in Casing Pressure

Maximum initial shut-in casing pressure, abbreviated as MISICP, based on the original mud weight before you start drilling ahead.  Once you drill deeper, you may increase mud weight.  With new mud weight, you are not able to use the MASICP calculated by the initial weight because higher mud weight will reduce the MASCIP.

 

Adjusted Maximum Allowable Shut-in Casing Pressure Formula The formula shows how to adjust the MASICP with new mud weight.
\( MASICP \;=\; LOP - [\; STVD \cdot (MW2 - MW1)\;] \cdot 0.052 \)
Symbol	English	Metric
\( MASICP \) = adjusted maximum allowable shut-in casing pressure (psi)	\(lbf\;/\;in^2\)	-
\( LOP \) = leak off pressure (pressure you get when you perform leak off test) (psi)	\(lbf\;/\;in^2\)	-
\( STVD \) = true vertical depth of casing shoe	\(ft\)	-
\( MW2 \) = current mud weight  (ppg)	\(lbs\;/\;gal\)	-
\( MW1 \) = origional mud weight (ppg)	\(lbs\;/\;gal\)	-