Standing Bubble Point & GOR Calculator

Petroleum reservoir fluid PVT: Determine bubble point saturation pressure (P_b), solution gas-oil ratio (R_s), and oil formation volume factor (B_o) using Standing classic empirical correlations.

Crude Oil & Solution Gas Parameters

Solution GOR R_s (SCF/STB): Dissolved gas at bubble point

Gas Specific Gravity γ_g: Relative to air (1.0)

Oil API Gravity (°API): Crude stock-tank density

Reservoir Temperature T (°F): In-situ reservoir temperature

Current Reservoir Pressure P (psia): Compare vs. Bubble Point

Correlation Type: Empirical PVT formulation

PVT Saturation & Volume Results

Bubble Point Pressure (P_b)

Oil Formation Volume Factor (B_o)

bbl / STB at P_b

Oil Specific Gravity (γ_o)

141.5 / (131.5 + °API)

Saturated Oil Density (ρ_o)

lb/cu ft in reservoir

Reservoir Saturation State

P vs. P_b comparison

Solution Gas Fraction (wt %)

Mass dissolved in oil

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Frequently Asked Questions

What does the oil formation volume factor Bo represent?

Bo represents the volume in barrels that one stock-tank barrel (STB at 60°F and 1 atm) occupies at reservoir temperature and pressure with its dissolved solution gas. Bo is always greater than 1.0 because dissolved gas and thermal expansion swell the oil volume.

What happens to Bo when reservoir pressure drops below the bubble point?

Above the bubble point (undersaturated region), Bo decreases slightly as pressure increases due to liquid compressibility. Below the bubble point, Bo decreases sharply because dissolved gas boils out of solution into the free gas phase, shrinking the remaining liquid oil.

When should Vasquez-Beggs be used instead of Standing?

Standing correlation was derived specifically from 105 experimental data points of California crude systems. Vasquez-Beggs (1980) was trained on over 6,000 global PVT data points and incorporates separate coefficient sets for heavy (API ≤ 30) and light (API > 30) crudes.