1. Chapter 10 – Properties of Black Oils - Reservoir Fluid Studies
PETE 310
Lecture # 17
Chapter 10 – Properties of Black Oils - Reservoir Fluid Studies

2. Fluid Properties for Reservoir Engineering Processes
The fluid properties of interest to the Reservoir Engineer are those that affect the mobility of fluids within the reservoirs these are used in material balance calculations
Properties at surface conditions for transportation and sales (API, viscosity, oil quality)

3. Fluid Properties for Reservoir Engineering Processes
PVT properties are determined from 5 specific lab procedures
Flash liberation tests
Differential Liberation Tests
Viscosity Measurements
Separator Tests
Compositional measurements

4. Fluid Properties Determined
Oil Properties
Bubble Point Pressure Bo Rs Bt
Co and mo
Gas properties z
Bg and mg
Compositions oil & gas

5. Oil Sampling Procedures
Bottom hole or subsurface samples
Separator Samples
SAMPLE BEFORE RESERVOIR PRESSURE DROPS BELOW Pb

6. 1.Flash Vaporization Test= b t5 t4
oil
gas Hg P 1
>> 2
> 3 4
< 5
< P
Temperature of Test = Reservoir Temperature

7. 1.Flash Vaporization Test
Properties determined Pb Co

8. Determination of Pb

9. Determination of Co

10. 2.Differential Separation Test
gas
oil Hg P 1 = b 2
< 3
< P 4 5
Gas off
Temperature of Test = Reservoir Temperature

11. 2.Differential Separation Test
Properties Determined
Oil formation volume factor at the Bubble Point pressure Bodb and below the bubble point pressure Bod
Solution gas-oil ratio at the Bubble Point pressure Rsdb and below the bubble point pressure Rsd
Isothermal compressibility (derived property)

12. 3. Separator Tests
Tests performed at a combination of different Temperature and Pressure pairs

13. 3. Separator Tests
Goals: Maximize API, minimize BoSb & RsSb

14. Optimization of Separator 2 Conditions
3160
3180
3200
3220
3240
3260
3280
3300
Solution Gas Oil Ratio at Pb (Rsb)
2.76
2.78
2.80
2.82
2.84
2.86
Formation Volume Factor at Pb (Bob) 50
100
150
200
250
300
Separator 2 Pressure (psia)
High Pressure 900 psia and T
Sep2
= 75 o F
100 ºF

15. Comparison between 1 & 2 Separators Stages (volatile oil)
3360
3380
3400
3420
3440
3460
Solution Gas Oil Ratio at Pb (Rsb)
2.90
2.92
2.94
2.96
Formation Volume Factor at Pb (Bob)
400
500
600
700
800
900
1000
Separator 1 Pressure (psia)
Low Pressure 300 psia and T
Sep1
= 160 o F
75ºF
One Separator Stage

16. Typical PVT Properties for a Black Oil and a Volatile Oil
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
Formation Volume Factor (Bo)
1000
2000
3000
4000
5000
Pressure (psia)
Black Oil
Volatile Oil
Black Oil Correlation T R
=180 o F P b

17. Typical PVT Properties for a Black Oil and a Volatile Oil
1000
2000
3000
4000
Solution Gas Oil Ratio (Rs)
5000
Pressure (psia)
Black Oil
Volatile Oil
Black Oil Correlation T R
=180 o F P b

18. Nomenclature

19. 4. Compositional Tests