Page tree

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

Synonym:Modified Black Oil (MBO) fluid @model = MBO fluid @model Volatile Oil fluid @model 


Specific case of a 3-phase fluid model based on three pseudo-components  

LaTeX Math Inline
bodyC = \{ W, O, G \}
:

LaTeX Math Inline
bodyW

water pseudo-component, which may include minerals  (assuming formation water and injection water composition is the same)

LaTeX Math Inline
bodyO

dead oil pseudo-component 

LaTeX Math Inline
bodyG

dry gas pseudo-component


existing in three possible 
phases 

LaTeX Math Inline
body\alpha = \{ w, o, g \}
:

LaTeX Math Inline
bodyw

water phase, consisting of Water component only

LaTeX Math Inline
bodyo

oil phase, consisting of dead Oil pseudo-component and dissolved dry Gas pseudo-componentt (called Solution Gas)

LaTeX Math Inline
bodyg

gas phase, consisting of dry Gas pseudo-component and vaporized dead Oil pseudo-component (called volatile oil)


The volumetric phase-balance equations is:

LaTeX Math Block
anchor1
alignmentleft
s_w + s_o + s_g =1

where

LaTeX Math Inline
bodys_w = \frac{V_w}{V}

share of total fluid volume

LaTeX Math Inline
bodyV
occupied by water phase
LaTeX Math Inline
bodyV_w

LaTeX Math Inline
bodys_o = \frac{V_o}{V}

share of total fluid volume

LaTeX Math Inline
bodyV
occupied by oil phase
LaTeX Math Inline
bodyV_o

LaTeX Math Inline
bodys_g = \frac{V_g}{V}

share of total fluid volume

LaTeX Math Inline
bodyV
occupied by gas phase
LaTeX Math Inline
bodyV_g


The accountable cross-phase exchanges are illustrated in the table below:


LaTeX Math Inline
bodyw

LaTeX Math Inline
bodyo

LaTeX Math Inline
bodyg

LaTeX Math Inline
bodyW

x

LaTeX Math Inline
bodyO


xx

LaTeX Math Inline
bodyG


xx


Volatile oil fluid model is widely used to model Volatile Oil Reservoir and Pipe Flow Simulations.

...


The relations  between in-situ and surface (usually SPE Standard Conditions (STP) ) flow properties are given by following equations (see Derivation):

LaTeX Math Block
anchorqO
alignmentleft
q_O =  \frac{q_o}{B_o} + \frac{R_v \, q_g}{B_g}
LaTeX Math Block
anchorqG
alignmentleft
q_G =\frac{q_g}{B_g} + \frac{R_s \, q_o}{B_o}
LaTeX Math Block
anchorqW
alignmentleft
q_W =  \frac{q_w}{B_w}
LaTeX Math Block
anchorq_o
alignmentleft
q_o = \frac{ B_o \cdot ( q_O - R_v \, q_G) }{1- R_v \, R_s}
LaTeX Math Block
anchorq_g
alignmentleft
q_g = \frac{ B_g \cdot ( q_G - R_s \, q_O)}{1- R_v \, R_s}
LaTeX Math Block
anchorq_w
alignmentleft
q_w = B_w \cdot q_W
LaTeX Math Block
anchorrho_o
alignmentleft
\rho_o = \frac{
\dot m_o}{q_o}= \frac{\rho_O + \rho_G \, R_s}{B_o}



LaTeX Math Block
anchorrho_g
alignmentleft
\rho_g = \frac{\dot m_g}{q_g}= \frac{\rho_G + \rho_O \, R_v}{B_g}



LaTeX Math Block
anchorrho_w
alignmentleft
\rho_w =\frac{\dot m_w}{q_w}=  \frac{\rho_W}{B_w}
LaTeX Math Block
anchorm_O1
alignmentleft
\dot m_O = \rho_O \cdot q_O
LaTeX Math Block
anchorm_G1
alignmentleft
\dot m_G = \rho_G \cdot q_G
LaTeX Math Block
anchorm_W1
alignmentleft
\dot m_W = \rho_W \cdot q_W
LaTeX Math Block
anchorm_o
alignmentleft
\dot m_o = \rho_o \cdot q_o = (\rho_O + \rho_G \, R_s) \cdot \frac{ q_o}{B_o}
LaTeX Math Block
anchorm_g
alignmentleft
\dot m_g = \rho_g \cdot q_g = (\rho_G + \rho_O \, R_v) \cdot \frac{q_g }{B_g}
LaTeX Math Block
anchorm_w
alignmentleft
\dot m_w = \rho_w \cdot q_w
LaTeX Math Block
anchorm_o
alignmentleft
\dot m_o = 
\frac{(\rho_O + \rho_G \, R_s) \cdot ( q_O - R_v \, q_G) }{1- R_v \, R_s}
LaTeX Math Block
anchorm_g
alignmentleft
\dot m_g = 
\frac{ (\rho_G + \rho_O \, R_v) \cdot ( q_O - R_v \, q_G) }{1- R_v \, R_s}
LaTeX Math Block
anchorm_w
alignmentleft
\dot m_w = \rho_W \cdot \frac{q_w}{B_w} = \rho_W \cdot q_W
LaTeX Math Block
anchorm_t
alignmentleft
\dot m = \dot m_o + \dot m_g + \dot m_w = \dot m_O + \dot m_G + \dot m_G 
LaTeX Math Block
anchorqt
alignmentleft
q_t = q_o + q_g + q_w
LaTeX Math Block
anchorqt2
alignmentleft
q_t = \frac{B_o - B_g \, R_s}{1-R_v \, R_s} \cdot q_O 

+\frac{B_g - B_o \, R_v}{1-R_v \, R_s} \cdot q_G 

+ B_w \cdot q_W
LaTeX Math Block
anchorqt3
alignmentleft
q_t = \frac{B_o - B_g \, R_s}{1-R_v \, R_s } \cdot \frac{\dot m_O }{\rho_O}

+\frac{B_g - B_o \, R_v}{1-R_v \, R_s } \cdot \frac{\dot m_G }{\rho_G}

+ B_w\cdot \frac{\dot m_W}{\rho_W}
LaTeX Math Block
anchorqt2
alignmentleft
\rho = \frac{\dot m}{q_t} = \frac{\dot m_O + \dot m_G + \dot m_G}{
\frac{B_o - B_g \, R_s}{1-R_v \, R_s } \cdot \frac{\dot m_O }{\rho_O}

+\frac{B_g - B_o \, R_v}{1-R_v \, R_s } \cdot \frac{\dot m_G }{\rho_G}

+ B_w\cdot \frac{\dot m_W}{\rho_W}
}

In-situ oil-cut:

LaTeX Math Block
anchorso
alignmentleft
s_o = \frac{q_o}{q_t} = \frac{ B_o \, (q_O - R_v \, q_G)}{(B_o - B_g \, R_s) \, q_O + (Bg - B_o \, R_v) \, q_G + B_w \, (1- R_v \, R_s) \, q_W }

In-situ gas-cut:

LaTeX Math Block
anchorso
alignmentleft
s_g = \frac{q_g}{q_t} = \frac{ B_g \, (q_G - R_s \, q_O)}{(B_o - B_g \, R_s) \, q_O + (Bg - B_o \, R_v) \, q_G + B_w \, (1- R_v \, R_s) \, q_W }

In-situ water-cut:

LaTeX Math Block
anchorso
alignmentleft
s_w = \frac{q_w}{q_t} = \frac{ B_w \, (1- R_v \, R_s) \, q_W}{(B_o - B_g \, R_s) \, q_O + (Bg - B_o \, R_v) \, q_G + B_w \, (1- R_v \, R_s) \, q_W }

The total fluid density:

LaTeX Math Block
anchorrho2
alignmentleft
\rho = s_o \, \rho_o + s_g \, \rho_g + s_w \, \rho_w

The total fluid compressibility:

LaTeX Math Block
anchorc
alignmentleft
c = s_o \, c_o + s_g \, c_g + s_w \, c_w 


See Also

...

Petroleum Industry / Upstream / Subsurface E&P Disciplines / Fluid (PVT) Analysis / Fluid @model

...