1. Basic Formulas

Table of Content

1. Pressure Gradient
2. Hydrostatic Pressure
3. Converting Pressure into Mud Weight
4. Specific Gravity
5. Equivalent Circulation Density
6. Maximum Allowable Mud Weight
7. Pump Output
8. Annular Velocity
9. Capacity Formulas
10. Control Drilling
11. Buoyancy Factor
12. Hydrostatic Pressure Decrease POOH
13. Loss of Overbalance Due to Falling Mud Level
14. Formation Temperature
15. Hydraulic Horsepower
16. Drill Pipe, Drill Collar Calculation
17. Pump Pressure, Pump Strokes
18. Cost Per Foot
19. Temperature Conversion Formulas

1.11 Buoyancy Factor (BF)

Buoyancy factor using mud weight, ppg

$\mathrm{BF}=\frac{65.5-\mathrm{mud\; weight,\; ppg}}{65.5}$

Example: Determine the buoyancy factor for a 15.0 ppg fluid:
$\mathrm{BF}=\frac{65.5-\mathrm{15.0}}{65.5}$
BF = 0.77099

Buoyancy factor using mud weight, lb/ft³

$\mathrm{BF}=\frac{489-{\mathrm{mud\; weight,\; lb/ft}}^3}{489}$

Example: Determine the buoyancy factor for a 120 lb/ft³ fluid:
$\mathrm{BF}=\frac{489-\mathrm{120}}{489}$
BF = 0.7546

⬆ Table of Content