1. Basic Formulas
Table of Content
- Pressure Gradient
- Hydrostatic Pressure
- Converting Pressure into Mud Weight
- Specific Gravity
- Equivalent Circulation Density
- Maximum Allowable Mud Weight
- Pump Output
- Annular Velocity
- Capacity Formulas
- Control Drilling
- Buoyancy Factor
- Hydrostatic Pressure Decrease POOH
- Loss of Overbalance Due to Falling Mud Level
- Formation Temperature
- Hydraulic Horsepower
- Drill Pipe, Drill Collar Calculation
- Pump Pressure, Pump Strokes
- Cost Per Foot
- Temperature Conversion Formulas
1.6 Maximum Allowable Mud Weight from Leak-off Test Data
ppg = (Leak-off Pressure, psi ) ÷ 0.052 ÷ (Casing Shoe TVD, ft) + (mud weight, ppg)
Example: leak-off test pressure = 1,140 psi, casing shoe TVD =
4,000 ft, and, mud weight = 10.0 ppg
ppg = 1,140 psi ÷ 0.052 ÷ 4,000 ft + 10.0 ppg
ECD = 15.48 ppg