Siam Engy
Engineering calculations — right in your pocket
SiamEngy combines interactive formulas, a unit converter, and an illustrated reference guide for the oil & gas industry. According to user reviews — the best app in its category.
Google Play
App Store
20,000+
downloads — across two platforms, iOS and Android
4.9 out of 5
average user rating in the app stores
50+
formulas — an interactive calculator for equations across seven field categories
100+
units of measurement — 20+ categories of quantities for conversion
Three tools in one
One screen — everything you need in the field or at school
The app is split into three logical blocks — each covers one task, with no need to switch between different programs and websites.
Formulas
An interactive calculator for 50+ equations across seven categories. Built-in numerical optimization algorithms find the unknown in the formula — no need to manually rearrange the variable.
Converter
Unit conversion for the most common field parameters. Pressure, temperature, rate, density, permeability, viscosity — no tables or searching needed.
Reference guide
Concise, illustrated articles about the parameters and processes behind the calculations. Context for every formula — at your fingertips, no textbook needed.
Flexible calculations
Any parameter — from any formula
The equation is calculated directly — analytically, like a regular calculator. To find any other parameter, a built-in optimizer picks its value so the equation balances.
- Instant calculation — forward and reverse calculations run without delay.
- Solution tuning — drag the parameter slider and see how it affects the result.
- Units on the fly — switch right in the calculation interface, without leaving the formula.
- Convergence check — every reverse calculation is verified with a direct calculation; if the result doesn't match, the app warns you.
- Multiple solutions — if a parameter has several possible values, the solver will warn you about it.
Seven formula categories
Equations for core field engineering tasks
Classical formulas
Dupuit's equation for steady-state and pseudo-steady-state flow, inflow calculations, hydraulics, fluid properties and other common calculations.
Production
ESP and SRP operating parameters, inflow calculations from fluid level and pressure, hydrostatics for static and dynamic fluid levels, intermittent well rate and dynamometer-based rate, pressure-to-depth conversion.
Gas wells
Gas properties, productivity of vertical and horizontal wells, bottomhole pressure, back-pressure testing, choke sizing, liquid loading and hydrate formation conditions.
Well testing
Productivity and average reservoir pressure evaluation, Vogel's equation, skin factor, wellbore storage effect and radius of investigation, time to pseudo-steady state.
Geology
Reservoir properties, oil density at reservoir conditions, geothermal gradient intersection point.
Drilling
Bit parameters and buoyancy factor, drilling mud density and weighting, annular flow hydraulics.
Well workover
Kill fluid density and volume, hydrochloric acid solution preparation, weight and volume of the rod string.
Interface
What SiamEngy looks like
Reviews
What users say
App Store · 61 ratings
Google Play · 145 reviews
The best app for an oil & gas engineer
Great app!!! I recommend it to everyone in the field. Much better and simpler than the "Oilman's Handbook" app
Great app! Special thanks for improving it based on comments and requests
Great app, probably the best I've come across for the oil industry!
The best thing out there for the oil industry...
Definitely 5 stars, thank you very much for this app
Great calculator for the oil industry
Good app, good luck with further development
This app really helps! Respect to the authors, it streamlined my team's work) recommend it!
A modern, intuitive interface with maximum functionality! Very convenient, especially the action history log and favorites.
Cool app, lets you quickly find the theory you need and also run calculations. For calculations there's also an option to choose different units of measurement
Great app
Great app! Convenient functionality and an extensive reference guide. You can keep the info and formulas you need in favorites and not waste time searching for them every time. Beginners will appreciate it)
Great app. Very convenient interface
The best app for an oil & gas engineer
Great app!!! I recommend it to everyone in the field. Much better and simpler than the "Oilman's Handbook" app
Great app! Special thanks for improving it based on comments and requests
Great app, probably the best I've come across for the oil industry!
The best thing out there for the oil industry...
Definitely 5 stars, thank you very much for this app
Great calculator for the oil industry
Good app, good luck with further development
This app really helps! Respect to the authors, it streamlined my team's work) recommend it!
A modern, intuitive interface with maximum functionality! Very convenient, especially the action history log and favorites.
Cool app, lets you quickly find the theory you need and also run calculations. For calculations there's also an option to choose different units of measurement
Great app
Great app! Convenient functionality and an extensive reference guide. You can keep the info and formulas you need in favorites and not waste time searching for them every time. Beginners will appreciate it)
Great app. Very convenient interface
Incredible how much work went into this. I actually started learning programming myself to build something similar. But then I stumbled on your app by accident — you can't even find it in search, which is a shame.
Thanks for such a useful app, hope you keep improving it!
Cool app! Thanks to the dev team
Great app.
Great app! Guys, don't stop here, keep going. There aren't many apps like this today — others charge a subscription and don't develop further. You could also expand the geology, production, and workover supervision sections. You're from Tomsk, and Tomsk's school has always been top-notch. I'd also tweak the design a bit.
Good app, intuitive and clear menu.
Best calculator 👍🤝
Cool... Very practical app. One request — add a gas rate calculation formula via a choke (DIKT)
A very convenient, easy-to-use app with a beautiful design. 👍
Great functionality and look. Everything is convenient and accessible.
A convenient and useful app!
Useful app, nice interface, everything is clear and informative! An indispensable tool for work!
Really liked the app. Simple, convenient, nothing extra, a large reference guide, plenty of useful formulas.
Incredible how much work went into this. I actually started learning programming myself to build something similar. But then I stumbled on your app by accident — you can't even find it in search, which is a shame.
Thanks for such a useful app, hope you keep improving it!
Cool app! Thanks to the dev team
Great app.
Great app! Guys, don't stop here, keep going. There aren't many apps like this today — others charge a subscription and don't develop further. You could also expand the geology, production, and workover supervision sections. You're from Tomsk, and Tomsk's school has always been top-notch. I'd also tweak the design a bit.
Good app, intuitive and clear menu.
Best calculator 👍🤝
Cool... Very practical app. One request — add a gas rate calculation formula via a choke (DIKT)
A very convenient, easy-to-use app with a beautiful design. 👍
Great functionality and look. Everything is convenient and accessible.
A convenient and useful app!
Useful app, nice interface, everything is clear and informative! An indispensable tool for work!
Really liked the app. Simple, convenient, nothing extra, a large reference guide, plenty of useful formulas.
Contains most of the equations you need
Recommend it to everyone in the industry)
A good helper for oil workers
Convenient app, everything is intuitively clear, awesome!
Super app
Fire app 👍
Why didn't I find this sooner
Beautiful, convenient, clear) a great app for people working in this field!)
Great app.
Great app, convenient and easy to use. Lets you quickly find the information you need. Recommend it.
Really cool app 5/5
Light, convenient app, I haven't seen a single ad and there are no hidden charges, hope the developers don't go down that road and monetize everything.
This is a real find! From the pleasant look to the functionality. Convenient and easy to use. Useful, makes calculations so much easier 💪
Contains most of the equations you need
Recommend it to everyone in the industry)
A good helper for oil workers
Convenient app, everything is intuitively clear, awesome!
Super app
Fire app 👍
Why didn't I find this sooner
Beautiful, convenient, clear) a great app for people working in this field!)
Great app.
Great app, convenient and easy to use. Lets you quickly find the information you need. Recommend it.
Really cool app 5/5
Light, convenient app, I haven't seen a single ad and there are no hidden charges, hope the developers don't go down that road and monetize everything.
This is a real find! From the pleasant look to the functionality. Convenient and easy to use. Useful, makes calculations so much easier 💪
The best app for an oil & gas engineer
Incredible how much work went into this. I actually started learning programming myself to build something similar. But then I stumbled on your app by accident — you can't even find it in search, which is a shame.
Contains most of the equations you need
Great app!!! I recommend it to everyone in the field. Much better and simpler than the "Oilman's Handbook" app
Thanks for such a useful app, hope you keep improving it!
Recommend it to everyone in the industry)
Great app! Special thanks for improving it based on comments and requests
Cool app! Thanks to the dev team
A good helper for oil workers
Great app, probably the best I've come across for the oil industry!
Great app.
Convenient app, everything is intuitively clear, awesome!
The best thing out there for the oil industry...
Great app! Guys, don't stop here, keep going. There aren't many apps like this today — others charge a subscription and don't develop further. You could also expand the geology, production, and workover supervision sections. You're from Tomsk, and Tomsk's school has always been top-notch. I'd also tweak the design a bit.
Super app
Definitely 5 stars, thank you very much for this app
Good app, intuitive and clear menu.
Fire app 👍
Great calculator for the oil industry
Best calculator 👍🤝
Why didn't I find this sooner
Good app, good luck with further development
Cool... Very practical app. One request — add a gas rate calculation formula via a choke (DIKT)
Beautiful, convenient, clear) a great app for people working in this field!)
This app really helps! Respect to the authors, it streamlined my team's work) recommend it!
A very convenient, easy-to-use app with a beautiful design. 👍
Great app.
A modern, intuitive interface with maximum functionality! Very convenient, especially the action history log and favorites.
Great functionality and look. Everything is convenient and accessible.
Great app, convenient and easy to use. Lets you quickly find the information you need. Recommend it.
Cool app, lets you quickly find the theory you need and also run calculations. For calculations there's also an option to choose different units of measurement
A convenient and useful app!
Really cool app 5/5
Great app
Useful app, nice interface, everything is clear and informative! An indispensable tool for work!
Light, convenient app, I haven't seen a single ad and there are no hidden charges, hope the developers don't go down that road and monetize everything.
Great app! Convenient functionality and an extensive reference guide. You can keep the info and formulas you need in favorites and not waste time searching for them every time. Beginners will appreciate it)
Really liked the app. Simple, convenient, nothing extra, a large reference guide, plenty of useful formulas.
This is a real find! From the pleasant look to the functionality. Convenient and easy to use. Useful, makes calculations so much easier 💪
Great app. Very convenient interface
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