01 / DRILLING
Hydrostatic Pressure
Estimate wellbore hydrostatic pressure from fluid density and true vertical depth.
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LIVE WELLBORE MODEL / 01 MODEL ACTIVE
HYDROSTATIC PRESSURE28.25 MPa
ANNULAR CAPACITY21.68 L/m
ANNULAR VELOCITY0.96 m/s
Illustrative calculations only. Uniform fluid, concentric geometry, and simplified annular flow assumptions.
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02 / RESERVOIR
Volumetric Estimation
Set up a reservoir volumetric workflow using area, thickness, porosity, and saturation.
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Production Rate Tools
Convert common flow-rate units and prepare production data for analysis.
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Completion Reference
Organize common completion parameters, units, and design reference values.
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Petrophysics Toolkit
Build toward porosity, water saturation, and formation evaluation calculations.
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Engineering Unit Converter
Switch between common field and SI units with instant results.
Convert units ↗07 / DRILLING
Annular Velocity
Estimate average fluid velocity in the annulus from flow rate and diameters.
Open calculator ↗08 / DRILLING
Equivalent Circulating Density
Estimate ECD using mud weight, annular pressure loss, and TVD.
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Pump Hydraulics
Estimate theoretical/actual pump flow and hydraulic horsepower.
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Pressure Loss
Calculate straight-pipe friction loss with the Darcy–Weisbach equation.
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Darcy Flow
Estimate single-phase linear flow using permeability and fluid properties.
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Water Cut & GOR
Calculate water cut and gas-oil ratio from daily production rates.
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Shale Volume (Vsh)
Estimate linear gamma-ray shale volume from clean and shale endpoints.
Open calculator ↗14 / COMPLETIONS
Cement Volume
Estimate annular cement volume with an optional excess allowance.
Open calculator ↗15 / FLUIDS
API Gravity & SG
Convert API gravity and specific gravity at the standard 60°F reference.
Open calculator ↗16 / RESERVOIR
Recovery Factor & Reserves
Estimate recoverable oil from an in-place volume and an assumed recovery factor.
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Inputs → Formula → ResultUnits are converted internally to a consistent base system.For education and preliminary estimation only. These tools do not replace approved well-control procedures, validated engineering software, or field-specific review.
DRILLING / TOOLKIT
ReadyHydrostatic pressure
ESTIMATED HYDROSTATIC PRESSURE28,252.8 kPa
✓Calculation summary
| Fluid density | 1,200 kg/m³ |
|---|---|
| Vertical depth | 2,400 m |
| Formula | P = ρ × g × TVD |
Assumes a uniform static fluid column and standard gravity (9.80665 m/s²). Does not include friction, dynamic effects, or other corrections.
RESERVOIR · PRODUCTION · COMPLETIONS · PETROPHYSICS
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RESERVOIR / VOLUMETRICS
ReadySTOIIP estimate
STOCK TANK OIL INITIALLY IN PLACE1.97 MMSTB
ƒxCalculation summary
| Formula | 7758 × A × h × φ × (1 − Sw) / Bo |
|---|
Volumetric estimate only. Assumes representative average properties and consistent field units; excludes uncertainty and recovery factor.
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Hydrostatic pressure
P = ρ × g × TVD
ρ in kg/m³, g = 9.80665 m/s², TVD in metres; result in pascals. Assumes a static, uniform fluid column.
Annular velocity
Vann = 24.51 × Q / (Dh² − Dp²)
Q in US gpm and diameters in inches; result in ft/min. Uses concentric circular geometry and average velocity.
Equivalent circulating density
ECD = MW + ΔPann / (0.052 × TVD)
MW in ppg, annular pressure loss in psi, TVD in ft; result in ppg. The friction pressure loss must be independently established.
STOIIP volumetrics
N = 7758 × A × h × φ × (1 − Sw) / Bo
A in acres, net pay in ft, porosity and saturation as fractions, Bo in rb/STB; result in STB.
Productivity index
J = qo / (Pr − Pwf)
Oil rate in STB/day and pressures in psi; result in STB/day/psi. Assumes a representative single-point operating condition.
Water cut and GOR
Water cut = qw / (qo + qw) × 100%; GOR = qg / qo
Rates must share the same reporting period; GOR here is scf/STB using gas and oil rates at consistent standard conditions.
Archie water saturation
Sw = [(a × Rw) / (φᵐ × Rt)]^(1/n)
Porosity as a fraction; Rw and Rt in consistent resistivity units. Archie assumptions are most suitable for clean formations with limited clay conductivity.
Darcy–Weisbach pressure loss
ΔP = f × (L/D) × ρ × v² / 2
Use the Darcy friction factor, consistent SI units, and a suitable factor for the flow regime. The tool excludes fittings and local losses.
API gravity
°API = 141.5 / SG(60°F) − 131.5
Specific gravity is referenced to water at 60°F. This is not a temperature-correction procedure for field density measurements.
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