GETTING STARTED
Project fluid
The one fluid every module in a project reads, where it comes from (black-oil correlations or an EOS model), and how to change it.
Overview
Each project has one project fluid. Wells, well test, material balance, decline (gas wells), the surface network, simulation, the integrated forecast and the AI Engineer all read their fluid properties from it, so they cannot disagree. You choose it on the PVT page with the Project fluid picker.
Sources
The project fluid comes from one of two sources:
| Source | Picker label | What it uses |
|---|---|---|
| Black-oil correlations | Black-oil correlations | The black-oil inputs on the PVT page (API gravity, gas gravity, GOR, reservoir temperature, water salinity) and the chosen correlation (Standing, Vasquez-Beggs, Glasø, Petrosky-Farshad or Al-Marhoun), including any tuning to lab data |
| Equation-of-state model | Equation of state: <model name> | One named compositional model from the project's model library |
A new project uses black-oil correlations. Its fluid is marked as not yet set, and the numbers behind it are typical placeholders (35 °API, gas gravity 0.75, 650 scf/STB, 200 °F). Modules that seed values from a placeholder fluid mark them with the typical-value badge.
If you import a compositional model into a project that has no fluid yet (for example one drafted from a lab report), that model becomes the project fluid automatically.
Change the project fluid
- Open PVT. The Project fluid picker is on both the black-oil and the compositional workspace.
- Choose Black-oil correlations or one Equation of state model.
- Converge confirms: "Project fluid changed. Every module now reads it."
Next to the picker, Converge shows a summary of the chosen fluid: the bubble point (or dew point for a gas condensate) and the GOR, in your unit system.
The choice is stored in the project, so it travels with saves, versions and exported project files.
What the summary holds
Every module can read these key properties of the project fluid. They are stored in field units and shown in your unit system.
| Property | Field unit | Notes |
|---|---|---|
| API gravity | °API | |
| Gas specific gravity | air = 1 | |
| Solution GOR at the bubble point | scf/STB | Separator basis. For a gas condensate, 10⁶ / CGR. |
| Reservoir temperature | °F | |
| Saturation pressure | psia | Bubble point for an oil, dew point for a gas condensate, at reservoir temperature |
| Water salinity | ppm | 30,000 ppm when none is entered |
| Saturation type | Bubble or dew |
Modules that need full properties against pressure (Bo, Rs, viscosity, Z and so on) use the full fluid model behind the summary, not the summary alone.
How modules use it
| Module | What it takes from the project fluid |
|---|---|
| Well performance | A new well's reservoir temperature and GOR; the fluid model for the well calculations |
| Well test | Use project fluid at pi: B, μ and ct follow the fluid at the initial pressure and update when pi or the fluid changes. Typing a value switches that input to manual. |
| Material balance | A PVT table built from the fluid model, from 14.7 psia up past the highest tank pressure |
| Decline & RTA | The fluid model for gas-well rate-transient analysis |
| Surface network | The fluid model for the network calculations |
| Simulation | The fluid model for the grid's PVT |
| Integrated forecast | A PVT table built from the fluid model, like material balance |
| AI Engineer | The fluid summary as project context |
Economics does not read the fluid.
If the chosen fluid cannot be built (for example an incomplete compositional model), the picker shows "cannot be built: see the PVT page" and the modules that need it report the problem instead of using a fallback.