This is the 3rd part of **well control formulas**.

**Annulus Capacity Factor (ACF),bbl/ft**

**Final Circulating Pressure (FCP), psi**

**Surface To Bit Strokes, strokes**

This is the 3rd part of **well control formulas**.

**Annulus Capacity Factor (ACF),bbl/ft**

**Final Circulating Pressure (FCP), psi**

**Surface To Bit Strokes, strokes**

These are some formulas used in well control operation. I will spit all content into several parts ^_^

**Equivalent Circulating Density (ECD) , ppg**

**Equivalent Circulating Density (ECD) ,ppg = (annular pressure loss, psi) ÷ 0.052 ÷ true vertical depth (TVD), ft + (current mud weight, ppg)**

**Leak-off Test Equivalent Mud Weight (LOT), ppg**

**Leak off test (ppg) = (Leak off test pressure in psi) ÷ 0.052 ÷ (Casing Shoe TVD in ft) + (Mud Weight used for LOT in ppg)**

**Maximum Initial Shut-In Casing Pressure (MISICP), psi**

This calculation is based on shoe fracture which is equal to Leak Off Test Pressure.

**MISICP (psi) = [LOT (ppg) – Current Mud Weight (ppg)] x 0.052 x Shoe TVD (ft)**

**Kill Mud Weight to Balance Formation (KMW), ppg**

**KWM (ppg) = [Shut In Drill Pipe Pressure (SIDP), psi ÷ (0.052x True Vertical Depth (TVD) of the well, ft)] + Original Mud Weight (ppg)**

**Slow Circulation Rate (SCR), psi**

**SCR (psi) = Initial Circulating Pressure (psi) – Shut In Drill Pipe Pressure (psi)**

**Ref book: ** **Formulas and Calculations for Drilling, Production and Workover, Second Edition**

Well Control Books

I would like to share with you about well control formulas that might be advantageous for you in the future. I seperate into several parts for you to easy to follow.

Before going into all calculations, I would like to emphasize about **rounding rules** that we will use for well control calculation.

**1. Kill Mud Density: **We must round up to one decimal place from a calculated kill mud density. For example, if we have the calculated kill mud density of 13.32 ppg, we will round it up to 13.4 ppg.

**2. Leak Off Test (LOT): **We must round down to one decimal place from a calculated Leak Off Test value. For example if we have the theoretical LOT of 15.57 ppg, we will round down to 15.5 ppg.

When any of the above values have been calculated, the rounded numbers must be used in subsequent calculations.

**Pressure (P) – psi**

**Pressure (psi) = Force (lb) / Area in Square Inch (in ^{2})**

**Pressure Gradient (G) – psi/ft**

**Mud Gradient ( Psi/ft ) = Mud weight ( PPG) x 0.052**