Defining fluid correlations
Fluid correlations are used to determine properties that are based on pressure, temperature, and fluid composition. Examples of some of these properties are: formation volume factor, density, and viscosity. For more information, see well fluid properties. Unlike pressure loss correlations, fluid correlation settings cannot be entered individually in the Well editor.
To define your fluid correlations:
1. Click the Properties menu and select Correlations.
The Correlations dialog box opens.
2. Click the Fluid Correlations tab.
3. To calculate hydrocarbon phase change, select the Calculate Phase Volume checkbox.
Select phase volume calculations for oil, or liquids-rich gas condensate systems.
4. If you selected Calculate Phase Volume in step 3, select a Phase Volume Correlation. Otherwise, continue to step 5.
The following data must be entered based on your selected phase volume correlation. This data can be entered in either the Defaults or Well editors, or both the Defaults and Well editors.
| Phase Volume Correlation | Required Data |
|---|---|
| Black Oil |
|
| Peng-Robinson or Wilson |
|
Data entered in the Defaults editor is applied globally to all wells. Data entered in the Well editor applies to each individual well. For further information on entering well fluid data, see well fluid properties.
For further information on phase volume correlations, see phase volume correlations.
5. Select the Gas PVT Correlation.
The Gas PVT Correlation field is selectable based on the Phase Volume Correlation selected in step 4, and requires additional data to be entered as follows:
| Correlation | Data for selected Gas PVT Correlation | ||
|---|---|---|---|
| Phase Volume Correlation | Gas PVT Correlation |
Benedict-Webb Rubin (B.W.R.) (Table), B.W.R. (8-constant), B.W.R. (11-constant) |
Piper Detail |
| No Phase Volume Correlation (i.e., not calculating phase volume) | can be selected |
Required- gas gravity | Required - C1 - C7+ detail composition. |
| Black Oil | can be selected | Required- gas gravity | n / a |
| Wilson | can be selected |
|
|
| Peng-Robinson | not selectable, properties are a direct output of Peng-Robinson |
|
|
If it exists, optional data that can be entered for all phase volume / gas PVT correlation combinations includes: H2S, N2, and CO2 volume percent impurities. For more information, see gas PVT correlations.
6. Select the Gas Viscosity Correlation.
No additional data entries are required for gas viscosity correlation options.
For more information, see gas viscosity correlations.
7. Select a Gas Type:
- Dry gas — for dry gas. This option corresponds to the miscellaneous gases curve in gas PVT correlations.
- Wet gas — select this option for most gas wells. This option corresponds to the condensate well fluids curve in gas PVT correlations.
Note: Gas Type is only available if you are not calculating phase volume. It requires no additional data entry.
8. Select your Oil PVT correlation and Oil Viscosity Correlation.
The Oil PVT and Viscosity Correlation fields are selectable based on the Phase Volume Correlation selected in step 4, and require additional data to be entered as follows:
| Correlation | |||
|---|---|---|---|
| Phase Volume Correlation | Oil PVT Correlation | Oil Viscosity Correlation | Required Data |
| No Phase Volume Correlation (i.e., not calculating phase volume) | can be selected |
can be selected | API gravity. |
| Black Oil | can be selected | can be selected | API gravity. |
| Peng-Robinson | not selectable, default is Peng-Robinsson | not selectable, default is Lorenz, Bray and Clark |
|
| Wilson | can be selected | not selectable, default is Lorenz, Bray and Clark |
|
For more information, see oil PVT correlations and oil viscosity correlations.
Only one PVT correlation for water exists and therefore it is automatically selected. The only data entry required is water specific gravity. Optionally, salinity can be entered in terms of parts per million.
9. Click OK.