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Drilling Engineering
14 in-depth calculators
Annular Velocity from Pump Output
Annular velocity from pump output estimates the average drilling-fluid velocity in the annulus from flow rate and annular area.
Annular Volume Capacity of Pipe
Annular Volume Capacity of Pipe calculates annular volume capacity for drilling hydraulics workflows in drilling engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Equivalent Circulating Density
Equivalent circulating density converts annular pressure loss into an effective mud-weight value at depth during circulation.
Equivalent Mud Weight from Surface Pressure
Equivalent Mud Weight from Surface Pressure calculates equivalent mud weight for well control workflows in drilling engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Final Circulating Pressure
Final circulating pressure estimates circulating pressure after kill-weight mud reaches the bit at the planned kill rate.
Hydrostatic Pressure from Mud Weight
Hydrostatic pressure from mud weight calculates the pressure exerted by a drilling-fluid column at true vertical depth using the standard oilfield 0.052 conversion factor.
Hydrostatic Pressure in Annulus Due to Slug
Hydrostatic Pressure in Annulus Due to Slug calculates hydrostatic pressure for well control workflows in drilling engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Initial Circulating Pressure
Initial circulating pressure estimates the pump pressure required at the start of a well-control circulation using slow circulating pressure and shut-in drillpipe pressure.
Kill Weight Mud Determination - Moore Equation
Kill weight mud determination estimates the mud density required to balance formation pressure after a kick using original mud weight, shut-in drillpipe pressure, and true vertical depth.
Maximum Allowable Annular Surface Pressure from Shoe EMW
Maximum allowable annular surface pressure estimates the casing-shoe pressure limit by comparing shoe equivalent mud weight with current mud hydrostatic pressure.
Maximum Drilling Rate for Larger Holes
Maximum Drilling Rate for Larger Holes calculates maximum drilling rate for drilling hydraulics workflows in drilling engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Pore Pressure Gradient - Rehm and McClendon
The Rehm and McClendon pore pressure gradient relationship estimates formation pore-pressure gradient from drilling or formation-evaluation indicators used in well planning.
Stuck Pipe Free Point from Pipe Stretch - Method 1
Stuck Pipe Free Point from Pipe Stretch - Method 1 calculates estimated free pipe length for drillstring and rig mechanics workflows in drilling engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Velocity of Fluid in Annulus
Fluid velocity in an annulus converts circulating flow rate and concentric annular geometry into an average linear velocity between the hole or casing and the drillpipe or tubing.
Geomechanics and Fracturing
6 in-depth calculators
Failure Criteria - Mohr-Coulomb Stress Components
Failure Criteria - Mohr-Coulomb Stress Components calculates shear stress on the plane for in-situ stress and rock mechanics workflows in geomechanics and fracturing. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Fracture Gradient - Zoback and Healy
Fracture gradient estimates the pressure gradient required to initiate or propagate a fracture under a stated stress model.
Minimum Hoop Stress at the Wellbore Wall
Minimum Hoop Stress at the Wellbore Wall calculates minimum hoop stress at the wellbore wall for in-situ stress and rock mechanics workflows in geomechanics and fracturing. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Normal Hoop Stress at the Wellbore Wall
Normal Hoop Stress at the Wellbore Wall calculates hoop stress at the wellbore wall for in-situ stress and rock mechanics workflows in geomechanics and fracturing. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Shale Compaction
Shale Compaction calculates compacted shale porosity for in-situ stress and rock mechanics workflows in geomechanics and fracturing. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Tangential Stress Extremes at a Deviated Wellbore
Tangential Stress Extremes at a Deviated Wellbore calculates maximum tangential stress for in-situ stress and rock mechanics workflows in geomechanics and fracturing. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Petrophysics
3 in-depth calculators
Archie Water Saturation from Resistivity Logs
Archie water saturation estimates formation water saturation from resistivity-log measurements, porosity, formation-water resistivity, and Archie exponents.
Indonesian Water Saturation from Shaly Sand Logs
The Poupon-Leveaux Indonesian equation estimates water saturation in shaly formations by combining formation-water and shale conductivity terms with effective porosity, shale volume, true resistivity, and saturation exponents.
Sonic Porosity Raymer-Hunt-Gardner Method
Sonic Porosity Raymer-Hunt-Gardner Method calculates sonic porosity for rock properties workflows in petrophysics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Phase Behavior and Thermodynamics
11 in-depth calculators
Beggs-Robinson Live Oil Viscosity Correlation
The Beggs-Robinson live-oil correlation estimates saturated oil viscosity from dead-oil viscosity and solution gas-oil ratio through correlation coefficients that capture the viscosity-reducing effect of dissolved gas.
Formation Water Salinity from Density
Formation Water Salinity from Density calculates water salinity or solids concentration for fluid properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Kinematic Viscosity for Saybolt Viscosimeter Measurements
Kinematic Viscosity for Saybolt Viscosimeter Measurements calculates kinematic viscosity for fluid properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
McCain Brine Gas-Solubility Salinity Correction
McCain Brine Gas-Solubility Salinity Correction calculates brine gas-solubility salinity correction factor for fluid properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Papay Gas Z-Factor Correlation
Papay Gas Z-Factor Correlation calculates gas compressibility factor for gas properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Real Gas Density
Real gas density estimates gas density at pressure and temperature using gas molecular weight or gravity and the real-gas z-factor.
Real Gas Isothermal Compressibility with Z-Factor Derivative
Real Gas Isothermal Compressibility with Z-Factor Derivative calculates real gas isothermal compressibility for gas properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Real Gas Pseudopressure Difference for Constant Mu-Z
Real Gas Pseudopressure Difference for Constant Mu-Z calculates real gas pseudopressure difference for gas properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Solution Gas-Oil Ratio - Standing Correlation
Solution Gas-Oil Ratio - Standing Correlation calculates solution gas-oil ratio for pvt properties workflows in phase behavior and thermodynamics. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Standing Oil Formation Volume Factor
Standing oil formation volume factor estimates the reservoir-barrel volume occupied by stock-tank oil and dissolved gas at reservoir pressure and temperature.
Vasquez-Beggs Solution Gas-Oil Ratio from Pressure
The Vasquez-Beggs correlation estimates solution gas-oil ratio from pressure, temperature, oil API gravity, gas specific gravity, and the coefficient set selected for the oil-gravity range.
Production Engineering
14 in-depth calculators
API RP 14E Erosional Velocity
The API RP 14E erosional velocity equation divides an empirical C factor by the square root of flowing mixture density to produce a screening velocity for gas-liquid production piping.
API RP 14E Two-Phase Flowline Pressure Drop
API RP 14E Two-Phase Flowline Pressure Drop calculates two-phase flowline pressure drop per 100 ft for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Carter Leakoff Volume for Hydraulic Fracturing
The Carter leakoff equation estimates hydraulic-fracturing fluid volume lost to the formation from leakoff area, Carter leakoff coefficient, exposure time, and instantaneous spurt-loss thickness.
Gas Deliverability Pressure-Squared Drawdown
Gas Deliverability Pressure-Squared Drawdown calculates pressure-squared drawdown for inflow performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Horizontal Separator Length for Liquid Retention
Horizontal Separator Length for Liquid Retention calculates required liquid settling section length for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Liquid-Liquid Vessel Retention Time
Liquid-Liquid Vessel Retention Time calculates retention time for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Productivity Index and Straight-Line IPR
Productivity index relates stabilized liquid production rate to reservoir-to-wellbore pressure drawdown and defines a straight-line inflow-performance relationship for a producing well.
Range of Load - Sucker Rod Pump
Range of Load - Sucker Rod Pump calculates range of load for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Rawlins-Schellhardt Gas Deliverability Rate
Rawlins-Schellhardt Gas Deliverability Rate calculates gas flow rate for inflow performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Separator Gas Capacity at Standard Conditions
Separator Gas Capacity at Standard Conditions calculates gas capacity at standard conditions for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Skin Factor Due to Reduced Crushed-Zone Permeability
Skin Factor Due to Reduced Crushed-Zone Permeability calculates skin factor due to reduced crushed-zone permeability for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Treatment Fracture Gradient - Hydraulic Fracturing
Treatment fracture gradient estimates the pressure gradient associated with hydraulic-fracturing treatment pressure at depth.
Velocity of Fluid in Pipe
Velocity of Fluid in Pipe calculates velocity of fluid in pipe for well performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Vogel Inflow Performance Relationship
The Vogel IPR estimates oil well inflow rate under two-phase flow conditions using flowing bottomhole pressure and average reservoir pressure.
Reservoir Engineering
24 in-depth calculators
API Gravity
API gravity converts oil specific gravity into the API gravity scale used to classify crude oil density in petroleum engineering workflows.
Buckley-Leverett Breakthrough Pore Volumes
Buckley-Leverett Breakthrough Pore Volumes calculates dimensionless breakthrough time for permeability and flow workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Capillary Number
Capillary number compares viscous forces with capillary forces and is commonly used as a rock-fluid screening parameter in displacement and recovery calculations.
Characteristic Time for Linear Diffusion in Reservoirs
Characteristic Time for Linear Diffusion in Reservoirs calculates characteristic diffusion time for pvt and rock-fluid properties workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Craft and Hawkins Vertical Well Critical Coning Rate
Craft and Hawkins Vertical Well Critical Coning Rate calculates critical oil rate without coning for well performance workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Cumulative Gas Production – Tarner’s Method
Cumulative Gas Production – Tarner’s Method calculates cumulative gas production for material balance and production workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Cumulative Oil Production – Undersaturated Oil Reservoirs
Cumulative Oil Production – Undersaturated Oil Reservoirs calculates cumulative oil production for pvt and rock-fluid properties workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Darcy's Law for Linear Single-Phase Flow
Darcy's law for linear single-phase flow estimates volumetric flow rate through porous rock from permeability, flow area, pressure drop, viscosity, and flow length.
Dimensionless Pressure for Linear Flow Constant Rate General Case
Dimensionless Pressure for Linear Flow Constant Rate General Case calculates dimensionless linear flow pressure for pressure transient analysis workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Fracture Conductivity During Bilinear Flow
Fracture Conductivity During Bilinear Flow calculates fracture conductivity for pressure transient analysis workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Gas Expansion Factor from Formation Volume Factor
Gas Expansion Factor from Formation Volume Factor calculates gas expansion factor for pvt properties workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Gas Formation Volume Factor
Gas formation volume factor converts gas volume between reservoir conditions and standard surface conditions using pressure, temperature, and gas z-factor.
Gas Produced by Gas Expansion
Gas Produced by Gas Expansion calculates gas produced by gas expansion for material balance and production workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Joshi Horizontal Well Productivity Index
The Joshi horizontal well productivity index estimates steady-state oil deliverability for a centered horizontal well by combining horizontal and vertical flow resistance, drainage geometry, anisotropy, well length, fluid properties, and skin.
Original Gas in Place - Volumetric Method
Original Gas in Place - Volumetric Method calculates original gas in place for reservoir volumetrics workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Original Oil in Place from General Oil Material Balance
Original oil in place from general oil material balance estimates OOIP by reconciling produced fluids, pressure change, expansion terms, and water influx in a reservoir material-balance relationship.
Pseudosteady-State Dimensionless Pressure Drop for Horizontal Well
Pseudosteady-State Dimensionless Pressure Drop for Horizontal Well calculates wellbore dimensionless pressure drop for pressure transient analysis workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Radial Pressure Distribution in Single-Phase Liquid Flow
Radial Pressure Distribution in Single-Phase Liquid Flow calculates pressure at radial position for fluid flow in porous media workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Radius of Investigation
Radius of Investigation calculates radius of investigation for pressure transient analysis workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Skin Factor from Pressure Transient Semilog Analysis
Skin Factor from Pressure Transient Semilog Analysis calculates skin factor for pressure transient analysis workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Steady-State Radial Liquid Flow Rate
Steady-state radial liquid flow rate estimates oil or liquid inflow toward a well from permeability, thickness, pressure drawdown, viscosity, formation volume factor, drainage radius, wellbore radius, and skin.
Tight Gas Pore Volume from Squared-Pressure Decline
Tight Gas Pore Volume from Squared-Pressure Decline calculates pore volume for unconventional reservoirs workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
van Everdingen-Hurst Single-Step Water Influx
van Everdingen-Hurst Single-Step Water Influx calculates cumulative water influx for pressure step for material balance workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Water Influx Constant for van Everdingen-Hurst Aquifer
Water Influx Constant for van Everdingen-Hurst Aquifer calculates water influx constant for material balance workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.