# ResToolbox3 — Petroleum Engineering Tools > Petroleum engineering calculator for PVT, nodal analysis, production forecasting, and more. (iPhone/iPad app by Mark Burgoyne.) - Source: https://appshunter.io/ios/app/restoolbox3/id6759464322 (this page in markdown: same URL + `.md`) - Developer: [Mark Burgoyne](https://appshunter.io/developer/497057811) - Category: Utilities, Productivity - Price: Free - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 13.0 · 24 MB - Languages: English - Released: 2026-03-11 - Data updated: 2026-07-09 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/restoolbox3/id6759464322/reviews.md ## What is 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 direct porosity methods, Pickett plot - Gas heating value and composition - Pipe capacities database (tubing, casing, drill pipe) - Unit converter with HC equivalents, reciprocal GOR/CGR, and density-gradient conversions DESIGNED FOR THE FIELD - iPhone-first interface with iPad responsive layouts - Oilfield and Metric unit systems with one-tap toggle - Share results and charts via email or messaging - Available in English, Norwegian, French, Chinese, Spanish, and Arabic - Works fully offline - no internet connection required - PVT properties flow between modules automatically All calculations use published, peer-reviewed methods from SPE literature and industry-standard references. No proprietary correlations, no curve-fitted shortcuts. Tabular data exports let you paste results directly into Excel or Google Sheets. ## Key features - Fluid properties (PVT) analysis - Gas hydrate prediction - Nodal analysis for wells - Production forecasting - Volumetric calculations - Well test analysis - Offline functionality ## Frequently asked questions about ResToolbox3 ### What petroleum engineering calculations can ResToolbox3 perform? ResToolbox3 offers a wide range of calculations including fluid properties (PVT), gas hydrate prediction, nodal analysis, production forecasting, volumetrics, and well testing. It covers complex scenarios like Peng-Robinson EOS for gas PVT and various correlations for oil PVT. ### Does ResToolbox3 work offline? Yes, ResToolbox3 is designed to work fully offline, requiring no internet connection. This makes it ideal for use in remote locations or areas with limited connectivity, such as rig floors or planes. ### What units does ResToolbox3 support? ResToolbox3 supports both Oilfield and Metric unit systems, with a one-tap toggle for easy switching. This ensures flexibility for engineers working with different regional standards. ### Can I share my results from ResToolbox3? Yes, you can share your results and charts directly from ResToolbox3 via email or messaging. This feature facilitates collaboration and reporting among engineering teams. ### What languages is ResToolbox3 available in? ResToolbox3 is available in English, Norwegian, French, Chinese, Spanish, and Arabic. This multilingual support enhances its accessibility for a global user base. ### Is ResToolbox3 suitable for beginners in petroleum engineering? While ResToolbox3 is a powerful tool for experienced engineers, its comprehensive features and specialized calculations are best suited for those with a foundational understanding of petroleum engineering principles. ### How often is ResToolbox3 updated? The latest version of ResToolbox3 is 3.0.5, last updated on April 19, 2026. Updates typically include improvements to calculation accuracy, new features, and expanded correlation support. ### Does ResToolbox3 have ads? No, ResToolbox3 does not contain advertisements. As a free application, it provides an uninterrupted user experience focused on engineering calculations. ## Version history (last 5 releases) ### 3.0.5 — 2026-04-19 - More accurate gas PVT at high pressures. - Improved brine water-content convergence near saturation. - Metric-mode fixes in Nodal Analysis, including non-Darcy flow. - Nodal Explorer: unit switching no longer resets outflow data. - Cleaner PVT property charts with better zoom on narrow ranges. - Stability and polish improvements throughout. ### 3.0.4 — 2026-03-23 Improvements: - Nodal analysis: Skin values clamped with Peaceman -0.75 correction - popup dialog explains the limit when values are adjusted - Nodal analysis: Injectivity denominator guard prevents division-by-zero edge cases Fixes: - Keyboard dismisses when tapping outside input fields on all screens - iOS keyboard overlay no longer obscures input fields - Resolved all Dart analyzer warnings ### 3.0.3 — 2026-03-21 New Features: - Appearance settings — choose between Auto, Light, or Dark theme mode - Dark mode support throughout the app with optimized colors and contrast Improvements: - Explorer mode: smart slider limits that scale with input values (permeability, pay height, CGR, excess GOR, FTHP) — no more clipped ranges for high-perm or thick reservoirs - FTHP slider capped at reservoir pressure in production mode; scales above Pr in injection mode - Tubing/casing ID sliders properly convert to metric units - Segmented button text contrast improved in dark mode - Localised app store descriptions and screen captures Fixes: - Unit toggle color corrected for dark theme AppBar - Dark mode text readability across all segmented controls ### 3.0.2 — 2026-03-20 What's New - PVT screens (Gas, Oil, Brine) now preserve results when switching between tabs - Standardized chart axis formatting across all screens - Improved chart tooltip readability - Methods & References section in share reports Bug Fixes - Fixed crash when running Probabilistic Volumes on iOS - Fixed layout error with notification messages ### 1.01 — 2026-03-14 - Oil PVT: Bt two-phase FVF on secondary log-scale axis - Brine PVT: pressure-sweep charts (Rsw, Bw, Cw) with saturated vs gas-free comparison - Undersaturated Co and Cw compressibility - All screens now update reactively - no Calculate button needed - Improved PVT data flow between modules - VLP performance optimisations - Bug fixes: Oil Co discontinuity, Outflow scaling, Brine Cw correction ## More apps by Mark Burgoyne - [Santos Convert](https://appshunter.io/ios/app/santos-convert/id1199279224) - [ResToolbox2](https://appshunter.io/ios/app/restoolbox2/id1252326018) All apps by Mark Burgoyne: https://appshunter.io/developer/497057811 ## Related topics [petroleum engineering](https://appshunter.io/ios/topics/petroleum-engineering) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-09.*