## Free Online PVT Calculator

Calculate the properties of petroleum reservoir fluids with a reliable, simple PVT calculator. Use the Vazquez-Beggs oil density calculator.

# Oil Density

Vazquez-Beggs (1980)
First-stage separator gas specific gravity
Stock-tank oil specific gravity
Solution gas-oil ratio at bubble point pressure

N.B. At pressures less than bubble point pressure, the Vazquez-Beggs (1980) correlations for the solution gas-oil ratio and the saturated oil formation volume factor are used to calculate the saturated oil density. At pressures greater than bubble point pressure, the Vazquez-Beggs (1980) correlation for the under-saturated oil compressibility is used to calculate the under-saturated oil density.

Want more details? Discover Vazquez-Beggs (1980) correlations.

## Fluid Property Behavior

### Oil Density

In this section, I would like to make sure that you can easily describe the behavior of your oil density at any reservoir pressure. Therefore, I will give you brief technical notes by answering three questions.
Why the oil density is maximum at the bubble point pressure?
When the pressure decreases above the bubble point pressure, the solution gas-oil ratio remains constant. As a result, the single-phase oil starts expanding, becoming relatively less dense, until the pressure reaches the bubble point pressure. On the other hand, when the pressure decreases below the bubble point pressure, more gas is liberating from the liquid phase, making the oil much denser. Actually, almost all the black oil properties respond differently to the decrease in reservoir pressure.
What are the black oil PVT properties that are affecting the value estimated for the oil density?
The oil density is strongly dependent on the values estimated for the bubble point pressure, the solution gas-oil ratio, the oil formation volume factor, and the oil compressibility.
What are the black oil PVT properties that depend on the value estimated for the oil density?
Actually, there is no black oil property that depends on the value estimated for the oil density.

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