1. Oil and water properties
PolyPVT
Oil and water properties
Lecturer: Marianna Dmitrieva
www. sofoil.com

2. Oil properties

3. API gravity determined from relative density
API oil gravity
The API gravity is the ratio of oil density to water density at the same temperature
API gravity determined from relative density
Conversion of barrels to tons

4. Typical API gravities Heavy Medium Light Gravity API Relative density
Specific weight, N/m3 8
1.014
1012 9
1.007
1005 10
1.000
998 15
0.966
964 20
0.934
932 25
0.904
302 30
0.876
874 35
0.850
848 40
0.825
823 45
0.802
800 50
0.780
778 55
0.759
757 58
0.747
745
Heavy
Medium
Light *

5. Bubble-point pressure
Bubble-point pressure is the pressure at which gas starts to release from liquid
Bubble-point pressure depends on
Oil to solution gas volume ratio
Oil and gas compositions
Reservoir temperature
*from PolyPVT

6. Solution gas to oil ratio
Gas-oil ratio is the ratio of the gas volume released from reservoir oil to the degassed oil volume
Rs – gas-oil ratio; Vg – gas volume; Vo surf – reservoir oil volume
Degassing
Contact
Differential

7. Gas-oil ratio vs. pressure
Gas liberation

8. Oil Formation Volume Factor
Oil Formation Volume Factor is the ratio of the reservoir oil volume to the volume of oil separated from it under standard conditions
! – for oil Bo > 1
Bo – Oil Formation Volume Factor; Vo res – reservoir oil volume; Vo surf – degassed oil volume
1/Bo is the Reciprocal Formation Volume Factor used to convert the volume of reservoir oil to oil volume at the surface
θ – Reciprocal Formation Volume Factor; Bo – Oil Formation Volume Factor

9. Formation Volume Factor vs. Pressure
Gas liberation

10. Oil compressibility Oil compressibility depends on
Oil compressibility is a property that describes how much the oil volume increases when the reservoir pressure decreases by 1 psi until it reaches the bubble-point pressure
120oC
40oC
Oil compressibility depends on
Temperature
Pressure
Oil and gas fractions
Gas-oil ratio

11. A falling-ball viscometer
Oil viscosity
Oil viscosity is a physical property that characterises oil mobility
A falling-ball viscometer
Operating principle

12. Viscosity vs. Pressure
Gas liberation

13. Water properties

14. Water salinity Dissolved salts: Salinity
Calcium chloride (magnesium/calcium chloride)
Hydrocarbonate (alkaline/sodium bicarbonate)
Salinity
Brine (> 50 g/l)
Saline (10–50 g/l)
Brackish (1–10 g/l)
Fresh (< 1 g/l)
Formation water types are defined by the ion content of dissolved salts
Anions OH-, Cl-, SO42-, CO32- and HCO3­Cations H+, K+, Na+, NH4+, Mg2+, Ca2+ and Fe3+
Microelement ions I- and Br-
Colloidal particles SiO2, Fe2O3 and Al2O3
Naphthenic acids and their salts

15. Water salinity in PolyPVT

16. Water Formation Volume Factor
The Water Formation Volume Factor relates the volume of water under reservoir conditions to that under standard conditions
Bw – water formation volume factor, Vw res – reservoir water volume, Vw surf – surface water volume
Range: 0.99–1.06

17. Formation Volume Factor vs. Pressure
Meehan

18. Water compressibility
Water compressibility is a property that shows how a unit water volume under reservoir conditions changes when the pressure changes by 1 psi
Water compressibility depends on
Temperature
Gas content
Salinity
Range: 3.7∙10-10 – 5∙10-10 Pa-1

19. Water viscosity Water viscosity mainly depends on Range: 0.2–1.5 cP
Water viscosity is a physical property that characterises water mobility
Water viscosity mainly depends on
Temperature
Salinity
Chemical composition
and to a smaller extent on
Gas content
Pressure
and to a smaller extent on
Gas content
Pressure
Range: 0.2–1.5 cP

20. Viscosity vs. Pressure
Meehan

21. THANK YOU!
www. sofoil.com