Gas Formation Volume Factor

Gas formation volume factor, abbreviated as \(B_g\), is the volume of gas at reservoir conditions (high pressure and high temperature) to the volume of gas at standard conditions (usually 14.7 psi and 60°F).

Importance

• Volumetric Calculations  -  This is used to convert gas volumes measured at reservoir conditions to standard conditions.  This conversion is essential for estimating reserves and for various calculations involving reservoir performance and production forecasting.
• Reservoir Engineering  -  It helps in understanding and modeling the behavior of gas in the reservoir, which is important for optimizing recovery and managing the reservoir effectively.

Practical Use

In practice, \(B_g\) values are often obtained from tables, charts, or software that use empirical correlations and measured data to provide accurate values under various reservoir conditions.  These resources are based on extensive experimental data and theoretical models.

 

Gas Formation Volume Factor formula
\( B_g \;=\;  0.005032 \; z \; T \;/\; p  \)     (Gas Formation Volume Factor) \( z \;=\;  B_g \; p \;/\; 0.005032 \; T  \) \( T \;=\;   B_g \; p \;/\; 0.005032 \; z  \) \( p \;=\;  0.005032 \; z \; T \;/\; B_g  \)
Symbol	English	Metric
\( B_g \) = gas formation volume factor	\(cu^3 \;/\; bbl\)	-
\( z \) = gas deviation factor	\(dimensionless\)	-
\( T \) = temperature	\(R\)	-
\( p \) = pressure (psi)	\(lbf \;/\; in^2\)	-