Comparison

i vs ResToolbox3

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

i

Features
Read full description

i-CTL is a splicing visual display and control solution developed by Guangdong AVCiT Technology Holding Co., Ltd. i-CTL has all basic intuitive & visualized functions, includes but not limited to real time content preview, virtual video wall layout, instantaneously drag/drop/zoom, grounding map, preset recalling, RTSP decoding, audio de-embedding, volume control, favourite folder, scheduled playing, and so on. It provide pixel perfect image over your existing network infrasture, with simplified cabling, and reduced IT infrastructure costs.

About

ResToolbox3

This petroleum engineering calculator provides rapid answers for engineers in the field or office. It offers comprehensive tools for fluid properties, gas hydrate prediction, nodal analysis, production forecasting, volumetrics, and well testing, all accessible offline.

Highlights
  • Fluid properties (PVT) analysis
  • Gas hydrate prediction
  • Nodal analysis for wells
  • Production forecasting
  • Volumetric calculations
  • Well test analysis
  • Offline functionality
Features
Read full description

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.

Screenshots

i4 screens
ResToolbox34 screens

Verdict

The call

The clearest difference is update cadence: ResToolbox3 at every 6 days against i's every 2 months. i's advantage is iOS requirement (9.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

i ships an update every 2 months, ResToolbox3 every 6 days. The most recent releases landed on October 4, 2026 and October 8, 2026 respectively.

Scorecard2 real differences · 7 level
i versus ResToolbox3: the parameters behind the verdict, then further details
ParameteriResToolbox3
PriceFreeFree
Rating—5.0 (2 ratings) — better
Number of ratings—2 — better
Update frequencyEvery 2 monthsEvery 6 days — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS9.0 — better15.0
Further details — not scored
Size26 MB25 MB
Age rating4+4+
DeveloperGuangdong AVCiT Technology Holding Co.,Ltd.MobileReservoir

In-app purchases

None

i

No in-app purchases

None

ResToolbox3

No in-app purchases

Questions

Is i free?
i is free to download, with no in-app purchases.
Is ResToolbox3 free?
ResToolbox3 is free to download, with no in-app purchases.
Do i or ResToolbox3 have ads?
Neither i nor ResToolbox3 shows ads.
Which is updated more often, i or ResToolbox3?
i ships an update every 2 months, and ResToolbox3 every 6 days. Most recently, i was updated on October 4, 2026 and ResToolbox3 on October 8, 2026.

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