## How to Calculate and Solve for Total Formation Volume Factor | The Calculator Encyclopedia

The image above represents the total formation volume factor (FVF).

To compute for the total FVF, four essential parameters are needed and these parameters are oil FVF (Bo), gas FVF (Bg), initial gas solubility (Rsi) and current gas solubility (Rs).

The formula for calculating the total FVF:

BT = Bo + (Rsi – Rs)Bg

Where;

BT = Total FVF
Bo = Oil FVF
Bg = Gas FVF
Rsi = Initial Gas Solubility
Rs = Current Gas Solubility

Let’s solve an example;
Find the total FVF when the oil FVF is 14, gas FVF is 15, initial gas solubility is 26 and current gas solubility is 17.

This implies that;

Bo = Oil FVF = 14
Bg = Gas FVF = 15
Rsi = Initial Gas Solubility = 26
Rs = Current Gas Solubility = 17

BT = Bo + (Rsi – Rs)Bg
BT = 14 + (26 – 17)15
BT = 14 + (9)15
BT = 14 + 135
BT = 149

Therefore, the total FVF is 149.

Calculating the Oil FVF when the Total FVF, Gas FVF, Initial Gas Solubility and Current Gas Solubility is Given.

Bo = BT – (Rsi – Rs)Bg

Where;

Bo = Oil FVF
BT = Total FVF
Bg = Gas FVF
Rsi = Initial Gas Solubility
Rs = Current Gas Solubility

Let’s solve an example;
Find the oil FVF when the total FVF is 44, gas FVF is 17, initial gas solubility is 21 and current gas solubility is 19.

This implies that;

BT = Total FVF = 44
Bg = Gas FVF = 17
Rsi = Initial Gas Solubility = 21
Rs = Current Gas Solubility = 19

Bo = BT – (Rsi – Rs)Bg
Bo = 44 – (21 – 19)17
Bo = 44 – (2)17
Bo = 44 – 34
Bo = 10

Therefore, the oil FVF is 10.

Calculating the Gas FVF when the Total FVF, Oil FVF, Initial Gas Solubility and Current Gas Solubility is Given.

Bg = BT – Bo / Rsi – Rs

Where;

Bg = Gas FVF
Bo = Oil FVF
BT = Total FVF
Rsi = Initial Gas Solubility
Rs = Current Gas Solubility

Let’s solve an example;
Find the gas FVF when the total FVF is 48, oil FVF is 16, initial gas solubility is 20 and current gas solubility is 12.

This implies that;

Bo = Oil FVF = 16
BT = Total FVF = 48
Rsi = Initial Gas Solubility = 20
Rs = Current Gas Solubility = 12

Bg = BT – Bo / Rsi – Rs
Bg = 48 – 16 / 20 – 12
Bg = 32 / 8
Bg = 4

Therefore, the gas FVF is 4.