pyResToolbox MCP Server

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:

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).