Basic Formulas
Capacities and Volumes for Downhole
Capacities
Volumes per Section
Capacities and Volumes of Tanks
Vertical Cylindrical Tanks
Rectangular Tanks
Horizontal Cylindrical Tanks
Content From Volume (Horiz. Tanks)
Pump Output and Rate Formulas
Pump Outputs
Pump Rates
Pumping Spotting Displacing
Pump Pressure Relationship
New Pump Pressure For Rate Change
New Pump Pressure For Density Change
Equivalent Circulating Density
Equivalent Circulating Density Using Pressure Loss
Equivalent Circulating Density Using Yield Point for MW <= 1.3 ppg
Equivalent Circulating Density Using Yield Point for MW > 1.3 ppg
Trip Calculations
Trip margin
Slug Mud Weight for a given Length of Dry Pipe
Slug Volume for a given Length of Dry Pipe
Pit Gain From Slug
Depth Slug Falls
Hydraulic Pressure Drop per Vertical Foot when Pulling Dry Pipe
Hydraulic Pressure Drop per Vertical Foot when Pulling Wet Pipe
Length of Dry Pipe Pulled Before Fill Up for Desired Pressure Drop 
Length of Wet Pipe Pulled Before Fill Up for Desired Pressure Drop 
Pressure and Gradient Formula
Fluid Gradient
Hydrostatic Pressure
Kick Related Formulas
Kick Sheet Calculations
Kill Weight From Original Mud Weight 
Initial Circulating Pressure 
Final Circulating Pressure 
Strokes To Bit
Strokes For KWM To Shoe
Strokes For KWM To Surface
Time For KWM To Bit
Time For KWM To Shoe
Time For KWM To Surface
Kick Related Formulas
Length Of Influx
Expected Pit Gain MPG With a Gas Kick in Water Based Mud System 
Expected Surface Pressure MSP From a Gas Kick In Water Based Mud System
Maximum Allowable Mud Weight 
Maximum Allowable Shut In Casing Pressure
Kick Tolerance With Influx
Estimated Kick Density
Kick Gradient
Gas Migration Distance
Rate Of Gas Migration
Kick Related Engineering
Bottom Hole Pressure While Circulating on The Choke
Equivalent Mud Weight At Bottom Hole While Circulating Out a Kick
Shut In Casing Pressure
Formation Pressure
pct Reduction in Hydrostatic Pressure Due To Gas Cut Mud For Water Based Mud
Leak Off Test Pressure And Equivalent Mud Weight At Shoe
Formation Integrity Test Pressure And Equivalent Mud Weight At Shoe
Maximum Formation Pressure That Can Be Controled With a Well Shut In
Maximum Kick Height Possible not To Exceed MASP
Maximum Kick Volume Possible not To Exceed MASP
Volumetric Method Calculations
Initial Pressure Build Increment
Cycle Pressure Build Increment
Hydrostatic Pressure Loss per Barrel of Mud in Upper Annulus
Bleed Volume Per Cycle
Lubricate and Bleed Calculations
Cycle Hydrostatic Pressure Gain per Barrel of Mud Pumped in Upper Annulus
Cycle Hydrostatic Pressure Increase or lubricated Volume To Be Bleed Off
Symple Formula
BullHeading Calculations
Kill Weight Mud
Formation Integrity Pressure at Perfs Depth
Hydraulic Pressure In Depth DrillPipe
Initial Maximum DrillPipe Pressure
Hydrostatic Pressure From KWM
Final Maximum DrillPipe Pressure
Stripping / Snubbing
BreakOver Point Between Stripping and Snubbing
Influx Height Gain From Stripping Info
Casing Pressure Increase From Stripping Into an Flux
Mud Volume To Bleed To Maintain Constant Bottom Hole Pressure
SubSea Formula
Riser Differential
Riser Margin
Pump StartUp Pressure on Casing Side
Initial Circulating Pressure
Final Circulating Pressure
Accumulator Sizing
Fluid Volume Required
Accumulator Usable Fluid Volume
Mud Cement Formula
Barite (100lb sx) per 100 bbl Required to Weight Up
Hematite (100lb sx) per 100 bbl Required to Weight Up
Pit Volume Increase per 100 bbl due to Weight Up With Barite
Final Mud Weight When Mixing Two Densities of Mud
Initial Mud Volume Required To Build a Final Volume of Mud With Barite
Cement Required (94lb sx)
Mix Fluid Required
Balanced Plug (Cement, Barite etc)
Hydraulics Formula
Annular Velocity 
Hydraulic HorsePower
Estimating and Rules Of Thumb
Tripping Rules of Thumb
Tripping Rules of Thumb
Stuck Pipe
Stuck Pipe
Free Point and Stretch Estimates
Free Point and Stretch Estimates
Estimating Teperature Drop Across a Choke or Orifice
Estimating Teperature Drop Across a Choke or Orifice
Bit Nozzle Pressure Loss
Bit Nozzle Pressure Loss
Estimating Gas Well Flow Rates
Estimating Gas Well Flow Rates
Area of Circle
Area of Circle
Force and Pressure
Force and Pressure
Weight of Spiral Drill Collars
Weight of Spiral Drill Collars
Buoyancy Factor (BF)
Buoyancy Factor (BF)
Surface and Bottom Hole Pressure in Full Gas Column
Surface and Bottom Hole Pressure in Full Gas Column
Pipe Elongation Due to Temperature
Pipe Elongation Due to Temperature
Applied Drilling Formula
Lag time
Light weight spot fill to balance formation pressure
Loss of hydrostatic pressure due to filling water into annulus in case of lost return
Pressure required to break circulation
Pump out (both duplex and triplex pump)
Pump Pressure and Pump Stroke Relationship 
Sutck Pipe Calculation
Ton Miles Calculation
Basic Formula
Accumulator capacity
Amount of cuttings drilled per foot of hole drilled
Annular Capacity 
Annular Velocity (AV)
Buoyancy Factor (BF)
Converting Pressure into Mud Weight
Drilling Cost Per Foot
D-Exponent and D-Exponent Corrected
Depth of washout
Displacment of plain pipe such as casing, tubing, etc.
Equivalent Circulating Density (ECD)
Formation Integrity Test (FIT)
Leak Off Test (LOT)
Formation Temperature
How many feet of drill pipe pulled to lose certain amount of hydrostatic pressure (psi)
Hydrostatic Pressure (HP)
Hydrostatic Pressure (HP) Decrease When POOH
Inner Capacity of open hole, inside cylindrical objects 
Pressure Gradient
Slug Calculation
Specific Gravity (SG)
Drilling Fluid
Bulk Density of Cuttings by using Mud Balance
Decrease oil water ratio
Determine oil water ratio from a retort analysis
Determine the density of oil/water mixture 
Dilution to control LGS
Increase mud weight by adding Barite
Increase mud weight by adding Calcium Carbonate
Increase mud weight by adding Hematite
Increase oil water ratio
Mixing Fluids of Different Densities with Pit Space Limitation
Mixing Fluids of Different Densities without Pit Space Limitation
Reduce mud weight by dilution
Engineering Formula
Annular Pressure Loss
Critical RPM
Calculate Equivalent Circulating Density with Engineering Formula
Well Control Formula
Adjusted maximum allowable shut-in casing pressure for new mud weight
Estimate gas migration rate with an empirical equation
Actual gas migration rate in a shut in well
Estimate type of inlux
Formaton pressure from kick analysis
Kick tolerance factor (KTF)
Maximum Initial Shut-In Casing Pressure (MISICP)
Maximum formation pressure (FP)
Maximum influx height
Maximum suface pressure from kick tolerance information
Trip margin
Directional Drilling Calculation
Directional Survey - Angle Averaging Method
Directional Survey - Radius of Curvature Method
Directional Survey - Balanced Tangential Method
Directional Survey - Minimum Curvature Method
Directional Survey - Tangential Method
Dogleg Severity Calculation based on Radius of Curvature Method
Dogleg Severity Calculation based on Tangential Method
Hydraulic Formula
Hydraulic Horse Power (HPP)