GETTING STARTED
Units
Field and Metric unit systems, how Converge converts values, the units each quantity uses, and why pressure is always absolute.
Overview
Converge has two unit systems: Field and Metric. Pick one with the Field / Metric switch in the top bar, or set it per project. Every input, table, chart and engine message follows the choice. Pressure is always absolute: psia in Field, bara in Metric.
How the choice works
- The top-bar switch changes the display at once. It is remembered in this browser.
- Project settings → Unit system stores a unit system with the project. When that project opens, the app switches to it. Not set keeps the top-bar choice.
- Switching units never changes your data. Converge stores every value in field units and converts only for display.
When you type a value in Metric, Converge converts it to field units before storing it. When it shows a stored value, it converts it to your unit system. Engine warnings that quote a value ("5053 psia", "2,000 ft") are rewritten into Metric too.
Saved projects, exported project files, the REST API and the scripting SDK hold field units only.
Units by quantity
| Quantity | Field | Metric | Factor (Field to Metric) |
|---|---|---|---|
| Pressure | psia | bara | × 0.0689476 |
| Pressure difference (drawdown, Δp) | psi | bar | × 0.0689476 |
| Temperature | °F | °C | (°F − 32) × 5/9 |
| Liquid rate | STB/d | Sm³/d | × 0.158987 |
| Gas rate | Mscf/d | kSm³/d | × 0.0283168 |
| Length, depth | ft | m | × 0.3048 |
| Diameter | in | mm | × 25.4 |
| Liquid volume | MMSTB | MSm³ | × 0.158987 |
| Gas volume | Bscf | MSm³ | × 28.3168 |
| Gas-oil ratio | scf/STB | Sm³/Sm³ | × 0.178108 |
| Oil formation volume factor | rb/STB | m³/Sm³ | × 1 |
| Gas formation volume factor | rb/scf | m³/Sm³ | × 5.614583 |
| Compressibility | 1/psi | 1/bar | × 14.5038 |
| Density | lbm/ft³ | kg/m³ | × 16.0185 |
| Viscosity | cp | mPa·s | × 1 |
| Wellbore storage | bbl/psi | m³/bar | × 2.30592 |
These quantities are the same in both systems: permeability (md), time (days), fractions, and money ($MM). A quantity built from others, such as a productivity index, converts from its parts (STB/d/psi becomes Sm³/d/bar).
Pressure basis
Every pressure input and result in Converge is absolute. Field shows psia, Metric shows bara. Pressure differences (drawdown, Δp, slope per log cycle) show psi or bar with no suffix.
Gauge pressures in imported data
When you paste or import tables, Converge reads the unit from the column header and converts gauge pressures to absolute.
- Data import reads psia, psig, bara, barg, kPa and MPa (gauge or absolute) from headers. Gauge values are converted with the Atmospheric pressure setting, 14.696 psia by default. Change it if your field's atmosphere differs.
- Material balance and Decline & RTA data tabs read the unit written in the header, for example
p (psia),pwf (barg),Pressure [psia]. They accept psia, psig, bara, barg and kPa (Material balance also MPa); gauge values are converted with 14.696 psia. - A column with no unit is read in the page's unit system: psia in Field, bara in Metric.
Number and date format
How numbers and dates look (digit grouping, date order) is separate from units. Set it in Project settings → Date and number format; it applies to this browser. Numbers always use a point as the decimal mark, so an input never misreads a value.