Oil Formation Volume Factor at saturation conditions

[PetEng]

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Homework Statement

Given the following data I need to find the oil formation volume factor at the saturation conditions;

A single flash separation of Angolan reservoir oil gave a stabilised (for stock tank) oil gravity of 37.19’ API and a gas gravity of 1.015. The GOR (gas oil ratio) of the separation measured as 1899 scf/stb. From a separation experiment (constant mass study) the density of reservoir oil at saturation pressure 3790psia and reservoir temperature 250F was determined to be 559.4kg/m3.
What is the oil formation volume factor at the saturation conditions?

oil gravity = 37.19API
gas gravity = 1.015
GOR = 1899 scf/stb
saturated reservoir oil density = 559.4 kg/m3

Homework Equations

The Attempt at a Solution

I used this method;

Bo = [ ρ(oil) + ρ(gas)*GOR(stb/stb)] / ρ(reservoir)
= [838.8 + 1.243*338] / 559.4

BO = 2.25 rb/stb

ρ(oil) = density of oil at surface (from 37.91 API)
ρ(gas) = density of gas at surface (using SGgas=1.015 to find MWgas and ideal gas equation PV=nRT to find density)
GOR (STB/STB) = 1899/5.615 = 338
ρ(reservoir) = density of reservoir oil at saturation = 559.4 kg/m3

Have I done this correctly?

 

[KataKoniK]

Yes, you have correctly calculated the oil formation volume factor at saturation conditions using the given data. Your method is correct and the resulting value of 2.25 rb/stb is accurate. It is important to carefully consider the units and conversion factors when using equations to solve problems in oil and gas reservoir engineering. Keep up the good work!