oil_sg_from_api
Convert oil API gravity to specific gravity for petroleum engineering calculations. Use this tool to transform API degrees into dimensionless specific gravity values essential for reservoir analysis.
Instructions
Convert API gravity to oil specific gravity.
UNIT CONVERSION TOOL - Converts API gravity (degrees) to specific gravity (dimensionless, water=1.0). Specific gravity is the ratio of oil density to water density at standard conditions. Essential for calculations requiring specific gravity.
Parameters:
api (float or list, required): Oil API gravity in degrees. Valid range: 0-100. Typical: 20-50. Example: 35.0 or [30, 35, 40]. Can be scalar or array.
Conversion Formula: SG = 141.5 / (API + 131.5)
Specific Gravity Ranges:
Heavy oil: SG > 0.922 (API < 22°)
Medium oil: SG 0.850-0.922 (API 22-35°)
Light oil: SG < 0.850 (API > 35°)
Water: SG = 1.0 (API = 10°)
Returns: Dictionary with:
value (float or list): Specific gravity (dimensionless, matches input api shape)
method (str): "Standard conversion"
units (str): "dimensionless (water=1)"
inputs (dict): Echo of input parameters
Common Mistakes:
Using gas API gravity instead of oil API gravity
Confusing API gravity with specific gravity (inverse relationship)
Not understanding that lower SG = lighter oil (higher API)
Using wrong conversion formula
Example Usage:
{
"api": 35.0
}Result: SG = 141.5 / (35.0 + 131.5) ≈ 0.850 (medium gravity oil)
Note: Most PVT correlations use API gravity directly, but some require specific gravity. Use this conversion when needed. Remember: API and SG are inversely related - higher API means lower SG (lighter oil).
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| request | Yes |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||