Navigation:  Prospect/Field evaluation > Entering probability distributions > Input Variables > Oil Formation Volume Factor

See also 'Entering Probability Distributions'.

 

Oil formation factor Bo accounts for the volume contraction of the oil as it moves from reservoir conditions to surface conditions, caused primarily by the liberation of dissolved gas. Bo is a number greater than 1.0:

 

Bo = {volume occupied at reservoir conditions} / {volume occupied at standard (stock tank) conditions}

 

Standard correlations are available to estimate Bo. These correlations may or may not be accurate and it is always best to use real data if you have it, or to pester your friendly reservoir engineer. This is especially true if your reservoir has high pressure and temperatures, or an unusually light or heavy oil.

 

In the volumetrics equation, Bo is in the denominator: REP makes the adjustment, and you should always enter it as a number greater than 1.0.