Reservoir Fluids Characteristics

Transcription

1 Properties of Reservoir Fluids (PGE 362) Reservoir Fluids Characteristics BY DR. MOHAMMED A. KHAMIS

2 Specific Gravity (γ o ): γ o = ρ o ρ w API = γ o γ o = API

3 Specific Gravity (γ o ): Example 8-1 (McCain book, page 225): Solution:

4 Oil Formation Volume Factor (Bo): Gas out of Solution Surface (Ps,Ts) Reservoir (P,T)

5 Oil Formation Volume Factor (Bo): The volume of reservoir oil required to produce one barrel of oil in the stock tank. B o = volume of oil + dissolved gas leaving reservoir at reservoir conditions volume of oil entering stock tank at standard conditions Units: res bbl/stb Factors affecting oil volume change: 1. Gas evolution 2. Pressure reduction 3. Temperature reduction

6 Oil Formation Volume Factor (Bo): Typical shape (Bo vs. Pressure): When the value of Bo = 1.0 res bbl/stb? b o = 1 B o? Search for: The temperature effect on Bo! (to be discussed next class)

7 Oil Formation Volume Factor (Bo): Example 8-2 (McCain book, page 226): Solution: B o = 400 res cc 274 ST cc = 1.46 res bbl STB

8 Oil Formation Volume Factor (Bo): Correlation: Black Oil Properties

9 Solution Gas Oil Ratio (Rs): The quantity of gas dissolved in oil at reservoir conditions. It is the amount of gas that evolves from the oil as the oil is transported from the reservoir to the surface conditions. R s = volume of gas produces at the surface at standard conditions volume of oil entering stock tank at standard conditions scf STB

10 Solution Gas Oil Ratio (Rs): Typical shape (Rs vs. Pressure): Search for: The temperature effect on Rs! (to be discussed next class)

11 Solution Gas Oil Ratio (Rs): Correlation: Black Oil Properties

12 Solution Gas Oil Ratio (Rs): Example 8-3 (McCain book, page 229): Calculate the solution gas oil ratio of the reservoir liquid of the previous example (Example 8-2). Solution: R s = volume of gas produces at the surface at standard conditions volume of oil entering stock tank at standard conditions scf STB R s = 1.21 scf 274 ST cc bbl/cc = 702 scf STB

13 Total Formation Volume Factor (B t ):

14 Total Formation Volume Factor (B t ): Also two-phase formation volume factor. B t = B o + B g R sb R s Units: bbl/stb + bbl/scf (scf/stb) = bbl/stb

15 Total Formation Volume Factor (B t ): Typical shape (B t vs. Pressure): Search for: The temperature effect on B t! (to be discussed next class)

16 Total Formation Volume Factor (B t ): Example 8-4 (McCain book, page 230): Solution: B t =???

17 The Coefficient of Isothermal Compressibility of Oil (Co): The instantaneous change of volume with pressure at constant temperature. Also called Oil Compressibility. C o = 1 V V P T With molar volume: C o = 1 V M Or; V M P T C o = 1 B o B o P T

18 The Coefficient of Isothermal Compressibility of Oil (Co): Above bubble point pressure: C o = 1 V V P T C o P 2 P 1 = ln V 2 V 1 V 2 = V 1 e C 0 P 1 P 2

19 The Coefficient of Isothermal Compressibility of Oil (Co): Above bubble point pressure Example 8-4 (McCain book, page 233): Solution: C o P 2 P 1 = ln V 2 V 1, C o = ln V 2 V 1 P 2 P 1 C o = ln = psi 1

20 The Coefficient of Isothermal Compressibility of Oil (Co): Below bubble point pressure: C o = 1 B o B o P T + B g B o R s P T

21 Oil Viscosity (µ o ): The measure of the resistance to flow exerted by a fluid. Dynamic viscosity: Units: (centipoise = g mass / 100 sec cm) Kinematic viscosity: viscosity / density Units: centistokes = centipoise /g/cc

22 Oil Viscosity (µ o ): Typical shape (µ o vs. Pressure): Search for: The temperature effect on B t! (to be discussed next class)

23 Oil Viscosity (µ o ): Importance: Calculation of two-phase flow Gas-lift and pipeline design Calculation of oil recovery either from natural depletion or from recovery techniques such as water flooding and gas-injection processes

24 Oil Viscosity (µ o ): Importance: Black Oil Properties

25 Oil Viscosity (µ o ): Importance: Black Oil Properties