Formation Volume Factor
Definition - What does Formation Volume Factor mean?
Formation Volume Factor is the ratio of the volume of dissolved gases and oil at reservoir pressure to the temperature at the surface. As most of the measurements of gas and oil production are carried out at the surface the volume factor is required for converting the surface volumes measured to reservoir conditions. The factor is almost always larger than 1.0 as the oil in the formation generally consists of dissolved gas which comes out from the solution in the borehole with low pressure.
Petropedia explains Formation Volume Factor
Formation Volume Factor is developed to facilitate the material balance calculations and aid the use of the low equations in the reservoir engineering. It is necessary to define the conditions when the volumes are reported, as volume of the phases differs a lot with temperature and pressure. These conditions are called base or standard conditions. The Formation Volume Factor is different for oil and gas:
Oil formation volume factor – Relates to the oil volume at the stock tank conditions with the oil volume at elevated temperature and pressure in reservoirs.
Gas formation volume factor – A useful relationship used for relating the volume of gases in reservoir to the produced gas volume at standard conditions.