oil_bubble_point
Calculate bubble point pressure for oil reservoirs using API gravity, temperature, and gas-oil ratio to determine when gas evolves from solution, essential for reservoir analysis and production planning.
Instructions
Calculate oil bubble point pressure (Pb).
CRITICAL PVT PROPERTY - The bubble point is the pressure at which gas first begins to evolve from solution in oil. Essential for all oil reservoir calculations.
Parameters:
api (float, required): Oil API gravity in degrees. Valid range: 0-100. Typical values: 20-50. Example: 35.0 for medium gravity crude.
degf (float, required): Reservoir temperature in degrees Fahrenheit. Valid range: -460 to 1000. Typical: 100-300°F. Example: 180.0.
rsb (float, required): Solution gas-oil ratio at bubble point in scf/stb. Must be ≥ 0. Typical: 100-3000 scf/stb. Example: 800.0.
sg_g (float, optional, default=0.0): Gas specific gravity (air=1.0). Valid range: 0-3. Typical: 0.6-1.2. Example: 0.75 for associated gas.
method (str, optional, default="VALMC"): Correlation method. Options: "STAN", "VALMC", "VELAR". VALMC recommended for wider applicability.
Method Selection:
VALMC (Valko-McCain 2003): Recommended. Best for wide range of conditions. Use for: Most applications, high GOR oils, wide temperature ranges.
STAN (Standing 1947): Classic correlation. Use for: Standard conditions, quick estimates, compatibility with older methods.
VELAR (Velarde 1997): Alternative method. Use for: Specific regional correlations, comparison studies.
Returns: Dictionary with:
value (float): Bubble point pressure in psia
method (str): Method used
units (str): "psia"
inputs (dict): Echo of input parameters
Common Mistakes:
Using separator temperature instead of reservoir temperature
Confusing rsb (solution GOR at bubble point) with separator GOR
Using gas gravity from wrong separator stage
Temperature in Celsius instead of Fahrenheit
Example Usage:
{
"api": 35.0,
"degf": 180.0,
"rsb": 800.0,
"sg_g": 0.75,
"method": "VALMC"
}Expected result: Pb ≈ 3000-4000 psia for typical oil.
Note: If Pb > reservoir pressure, reservoir is undersaturated (no free gas). If Pb < reservoir pressure, reservoir is saturated (gas cap present).
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| request | Yes |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||