ResToolbox3

ResToolbox3 is a petroleum engineering calculator built for engineers who need answers fast - on a rig floor, in a meeting, or on a plane. PVT analysis, nodal analysis, gas hydrate prediction, production forecasting, volumetric calculations, and well testing, all from your iPhone or iPad.

FLUID PROPERTIES (PVT)
- Gas PVT: Z-factor, viscosity, compressibility, pseudo-pressure, water content, and thermal properties via 5-component Peng-Robinson EOS. Handles CO2, H2S, N2, H2, and hydrocarbon mixtures including pure and high-concentration cases
- Oil PVT: Bubble point, solution GOR, formation volume factor, viscosity, and compressibility using Valko-McCain and Velarde correlations. Three solve modes with scaling factors for GOR and viscosity
- Brine & Rock: Soreide-Whitson mutual solubility with Spivey brine correlations. Gas composition from Gas PVT flows through automatically

GAS HYDRATES
- Hydrate formation prediction via Motiee and Towler-Mokhatab correlations
- Thermodynamic inhibitor dosing for MEG, DEG, TEG, methanol, and ethanol
- Interactive P-T stability curves with inhibited and uninhibited envelopes
- Water content mass balance between reservoir and operating conditions

NODAL ANALYSIS
- Gas and oil well inflow performance (IPR) with non-Darcy flow and Vogel
- Outflow performance (VLP) via four methods: Woldesemayat-Ghajar, Hagedorn-Brown, Beggs & Brill, and Gray
- 3x3 sensitivity matrix or real-time Explorer mode with interactive sliders
- Water cut modelling with physics-based two-phase flow
- Injection well support

PRODUCTION FORECASTING
- Single-well decline profiles: hyperbolic, exponential, and harmonic
- Two-stage decline with continuous slope matching
- Multi-well field development with drilling schedule, plateau constraints, and abandonment rate

VOLUMETRICS
- Deterministic OGIP and OOIP with combined gas/oil mode
- Monte Carlo probabilistic analysis with Normal, Log-Normal, and Triangular distributions
- Exceedance probability curves with P90, P50, and P10 reporting

WELL TEST & TOOLS
- Choke flow: gas mode (Gilbert, Norsok, TAM, SLB) and oil mode (Gilbert, Ros, Baxendell, Achong)
- AGA-3 orifice metering for gas and ISO 5167 for liquid
- Gas flowline pressure drop: 30-segment Darcy-Weisbach with PR-EOS properties at each segment, plus Weymouth and Panhandle B empirical methods
- Petrophysics: Archie equation with density, sonic, and dir