Drilling Formulas Calculations are not difficult to perform, and after downloading this free spreadsheet, you will find how easy they are. In this spreadsheet you will find that it is divided into many sections:

- Applied Drilling Formulas
- Basic Drilling Formulas
- Directional Drilling Calculation
- Drilling Fluid Formulas
- Engineering Formulas
- Hydraulics Formulas
- Well Control Formulas
- Drill String Design
- Cementing

## Applied Drilling Formulas Calculations Spreadsheet

This section includes the following formulas:

- Drill Collar Weight Calculation
- Effective Mud Density
- Equivalent Circulating Density (ECD) Using drilling mud Yield Point for MW less than or equal to 13 ppg
- Equivalent Circulating Density (ECD) Using Yield Point for MW more than 13 ppg
- Lag time
- Light weight spot fill to balance formation pressure
- Loss of hydrostatic pressure due to filling water into the annulus in case of circulation lost return
- Margin of Over Pull (MOP)
- Maximum ROP Before Fracturing Formation
- Pipe Elongation Due to Temperature
- The Pressure required to break circulation
- Mud Pump output calculations (both duplex and triplex pump)
- Pump Pressure and Pump Stroke Relationship
- Stuck Pipe Calculation ( check also free point calculation for stuck pipe)
- Ton Miles Calculation
- Volume of Cutting Generated While Drilling

## Basic Drilling Formulas

In this Basic Drilling Formulas calculations, you shall find the following:

- BOP Accumulator Capacity
- Amount of cuttings drilled per foot of hole drilled
- Annular Volume Capacity Calculations
- Annular Velocity (AV)
- Buoyancy Factor (BF)
- Buoyancy Factor (BF) with different fluid weights inside and outside
- Convert Temperature Unit
- Converting Pressure into Mud Weight
- Coring Cost Per Footage Recovered
- Depth of drill pipe washout
- D-Exponent and D-Exponent Corrected
- Displacement of plain pipe such as casing, tubing, etc.
- Drilling Cost Per Foot
- Equivalent Circulating Density (ECD)
- Formation Integrity Test (FIT) & Leak off Test
- Formation Temperature
- How many feet of drill pipe are pulled to lose a certain amount of hydrostatic pressure (psi)
- Hydrostatic Pressure (HP)
- Hydrostatic Pressure (HP) Decrease When POOH
- Inner Capacity of open holes inside cylindrical objects
- Leak Off Test (LOT)
- Pressure and Force
- Pressure Gradient
- Slug Calculation
- Specific Gravity (SG)
- Total Bit Revolution in downhole drilling Mud Motor

## Directional Drilling Calculation

Drilling Formulas website also didn’t forget to add the directional drilling calculations which contain the following:

- Directional Survey Calculation – 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 the Radius of Curvature Method
- Dogleg Severity Calculation based on the Tangential Method

## Drilling Fluid Formulas

We have gathered the drilling fluids calculations in our previous articles; we recommend visiting them first for more information. This free download spreadsheet section includes the following drilling formulas calculations:

- Bulk Density of Cuttings by using Mud Balance
- Decrease oil-water ratio
- Determine the oil-water ratio from a retort analysis
- Determine the density of the oil/water mixture.
- Dilution to control LGS
- Increase mud weight by adding Barite in drilling mud
- Increase mud weight by adding Calcium Carbonate
- Increase mud weight by adding Hematite
- Increase the oil-water ratio.
- Mixing Fluids of Different Densities with Pit Space Limitation
- Mixing Fluids of Different Densities without Pit Space Limitation
- Plastic Viscosity (PV) and Yield Point (YP) from mud test
- Reduce mud weight by dilution
- Solid Density From Retort Analysis

## Engineering Formulas

- Annular Pressure Loss
- Critical RPM
- Calculate Equivalent Circulating Density with Engineering Formula
- Bottom Hole Pressure from Wellhead Pressure in a Dry Gas Well

## Hydraulic Formulas

Previously in our drilling hydraulics section, we have discussed all drilling hydraulics calculations and we also provided drilling hydraulics calculators to be used by drilling engineers. This section also include the following drilling formulas calculations:

- Bit Nozzle Velocity
- Bit Aggressiveness
- Bit Hydraulic Horsepower
- Bit Hydraulic Horsepower Per Area of Dril Bit (HSI)
- Critical Flow Rate
- Cross Flow Velocity Under a Drilling Bit
- Cutting Carrying Index
- Cutting Slip Velocity Method#1
- Cutting Slip Velocity Method#2
- Effective Viscosity
- Hydraulic Horse Power (HPP)
- Impact Force of Jet Nozzles on Bottom Hole
- Mechanical Specific Energy
- Minimum Flow Rate PDC bit
- Optimum Flow Rate for basic system
- Power Law Constant
- Pressure Drop Across Bit
- Pressure Loss Annulus
- Pressure Loss Annulus With Tool Joint Correction
- Pressure Loss Drillstring
- Pressure Loss Drillstring With Tool Joint Correction
- Pressure Loss in Surface Equipment
- Reynold Number
- Surge and Swab Pressure Method#1
- Surge and Swab Pressure Method#2
- Total Flow Area Table

## Well Control Drilling Formulas Calculations

We recommend visiting our well control section first, that have a full explanation of drilling kicks, how to deal with them, and the killing procedures ( driller method – Wait & weight killing method)

- Actual gas migration rate in a shut-in well
- Adjusted maximum allowable shut-in casing pressure for new mud to calculate Influx Height
- Estimate gas migration rate with an empirical equation
- Estimate the type of influx
- Final Circulating Pressure (FCP)
- Formation pressure from kick analysis
- Hydrostatic Pressure Loss Due to Gas-Cut Mud
- Increase in Casing Pressure due to Kick Penetration
- Initial Circulating Pressure (ICP)
- Kick tolerance factor (KTF)
- Kill Weight Mud
- Lube Increment
- Maximum formation pressure (FP)
- Maximum influx height
- Maximum Initial Shut-In Casing Pressure (MISICP)
- Maximum pit gain from gas kick in water-based mud
- Maximum Surface Pressure from Gas Influx in Water-Based Mud
- Maximum surface pressure from kick tolerance information
- Mud Increment

## Free Download Formulas & Calculations For Drilling Operations

Thanks to the drilling formulas team that prepared this spreadsheet