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Grid-related Computation

(1) \epsilon = \text{1e-12}




(2) v_{\alpha\beta} = \frac{V_{\alpha\beta}}{V_{\alpha\beta} + V_{\beta\alpha}}




(3) COS2_{\alpha\beta} = \left( \bar n_{\alpha\beta} \cdot \; \bar e_{k\max} \right)^2




(4) Rg_{\alpha\beta} = R_{\alpha\beta} \cdot g \cdot \sqrt{1-COS2_{\alpha\beta}}




(5) Rk_{11\alpha\beta} =  R^{-1}_{\alpha\beta}  \cdot \left( k_{\max\alpha\beta} \cdot COS2_{\alpha\beta} + k_{\min\alpha\beta} \cdot (1 - COS2_{\alpha\beta}) \right)




(6) \tilde B_w = \tilde B_w(T,p) = B_w
(7) \tilde B_o = \tilde B_o(T,p) = \frac{B_o - R_s \cdot B_g}{1-R_s \, R_v}
(8) \tilde B_g = \tilde B_g(T,p) = \frac{B_g - R_v \cdot B_o}{1-R_s \, R_v}

(9) c_\phi(p) = \left[ \, \text{table interpolation} \, \right ]

or

Dobrynin Pore compressibility-pressure @model :


(10) \displaystyle c_\phi(p) = c_{\phi i} \cdot \frac{ \ln \left( \frac{ p_n }{p_{\rm max}} \right) }{ \ln \left( \frac{p_{ni}}{p_{\rm max}} \right) }
(11) p_n = p_{\rm min} + 1.75 \cdot \phi^{0.51} \cdot (p_{\rm max} - p)
(12) p_{ni} = p_{\rm min} + 1.75 \cdot \phi^{0.51} \cdot (p_{\rm max} - p_i)
Wide pressure range: pmin = 1 MPa < p < pmax = 200 MPa





Initialization: t = 0

(13) s^0_{w\alpha} = s_{wi\alpha}
(14) s^0_{o\alpha} = s_{oi\alpha}
(15) s^0_{g\alpha} = s_{gi\alpha}



(16) V^0_{\phi\alpha} = V_\alpha \cdot \phi^0_\alpha, \quad \phi^0_\alpha = \phi^0_{i\alpha}
(17) V^0_{w\alpha} = s^0_{w\alpha} \cdot V^0_{\phi\alpha}


(18) V^0_{o\alpha} = s^0_{o\alpha} \cdot V^0_{\phi\alpha}
(19) V^0_{g\alpha} = s^0_{g\alpha} \cdot V^0_{\phi\alpha}



(20) V^0_{W\alpha} = \frac{V^0_{w\alpha}}{B_{wi}}
(21) V^0_{O\alpha} =\frac{V^0_o}{B_{oi}} + R_{vi} \cdot \frac{V^0_g}{B_{gi}}


(22) V^0_{G\alpha} =\frac{V^0_G}{B_{gi}} + R_{si} \cdot \frac{V^0_o}{B_{oi}}



(23) I^0_{W\alpha} = \frac{V^0_{W\alpha}}{V^0_{\phi\alpha}}
(24) I^0_{O\alpha} = \frac{V^0_{O\alpha}}{V^0_{\phi\alpha}}
(25) I^0_{G\alpha} = \frac{V^0_{G\alpha}}{V^0_{\phi\alpha}}



(26) p^0_{w\alpha} = p^0_\alpha + p_{cw}(s^0_\alpha)

(27) p^0_{o\alpha} = p^0_\alpha + p_{co}(s^0_\alpha)

(28) p^0_{g\alpha} = p^0_\alpha + p_{cg}(s^0_\alpha)

(29) U^0_{W\alpha\beta} = 0
(30) U^0_{O\alpha\beta} = 0
(31) U^0_{G\alpha\beta} = 0






Progression: t → t + 1


Loop Over

Cross-Cell Face Saturation
(32) s^t_{w\alpha\beta}=s^t_{w\alpha} \cdot v_{\alpha\beta} + s^t_{w\beta}\cdot v_{\beta\alpha}
(33) s^t_{o\alpha\beta}=s^t_{o\alpha} \cdot v_{\alpha\beta} + s^t_{o\beta}\cdot v_{\beta\alpha}
(34) s^t_{g\alpha\beta}=s^t_{g\alpha} \cdot v_{\alpha\beta} + s^t_{g\beta}\cdot v_{\beta\alpha}

Cell Relative Permeability

(35) k_{rw\alpha\beta} = k_{rw}(s^t_{\alpha\beta})
(36) k_{ro\alpha\beta} = k_{ro}(s^t_{\alpha\beta})
(37) k_{rg\alpha\beta} = k_{rg}(s^t_{\alpha\beta})

Fluid Phase Viscosity

(38) \mu_{w\alpha\beta} = \mu_w(p^t_{w\alpha\beta})
(39) \mu_{o\alpha\beta} = \mu_o(p^t_{o\alpha\beta})
(40) \mu_{g\alpha\beta} = \mu_g(p^t_{g\alpha\beta})

Phase Densities




(41) \rho_{w\alpha} = {\mathring \rho_W} \, \cdot I\!B^t_{w\alpha}
(42) \rho_{o\alpha} = \left( \mathring \rho_O + \mathring \rho_G \cdot R^t_{s\alpha} \right) \cdot I\!B^t_{o\alpha}
(43) \rho_{g\alpha} = \left( \mathring \rho_G + \mathring \rho_O \cdot R^t_{v\alpha} \right) \cdot I\!B^t_{g\alpha}

Capillary and Gravity Cell Centre-to-Face Pressure Drop




(44) \delta p_{w\alpha\beta} = p_{cw}(s^t_{\alpha\beta}) - p_{cw}(s^t_{\alpha}) - \rho_{w\alpha} \cdot Rg_{\alpha\beta}
(45) \delta p_{o\alpha\beta} = p_{co}(s^t_{\alpha\beta}) - p_{co}(s^t_{\alpha}) - \rho_{o\alpha} \cdot Rg_{\alpha\beta}
(46) \delta p_{g\alpha\beta} = p_{cg}(s^t_{\alpha\beta}) - p_{cg}(s^t_{\alpha}) - \rho_{g\alpha} \cdot Rg_{\alpha\beta}

Multiphase Cross-Cell Face Pressure

(47) p^t_{\alpha\beta} = s^t_{w\alpha\beta} \cdot p^t_{w\alpha \beta} + s^t_{o\alpha\beta} \cdot p^t_{o\alpha \beta} + s^t_{g\alpha\beta} \cdot p^t_{g\alpha \beta}
(48) k_{p\alpha\beta} = k_{\alpha\beta}(\phi^t_{\alpha \beta})

or

(49) k_{p\alpha\beta} = \exp \left[ \; c_{k\alpha\beta} \cdot \left( p^t_{\alpha \beta} - p_{0\alpha \beta} \right) \; \right]
(50) kRk_{11\alpha\beta} = k_{p\alpha\beta} \cdot Rk_{11\alpha\beta}
(51) G_{W\alpha\beta} = \frac{k_{rw\alpha\beta}}{\mu_{w\alpha\beta}} \cdot kRk_{11\alpha\beta}
(52) G_{o\alpha\beta} = \frac{k_{ro\alpha\beta}}{\mu_{o\alpha\beta}} \cdot kRk_{11\alpha\beta}
(53) G_{g\alpha\beta} = \frac{k_{rg\alpha\beta}}{\mu_{g\alpha\beta}} \cdot kRk_{11\alpha\beta}

(54) T_{W\alpha\beta}  = I\!B^t_{w\alpha} \cdot G_{w\alpha\beta}
(55) T_{O\alpha\beta}  = I\!B^t_{o\alpha}  \cdot   G_{o\alpha\beta} + R_{v\alpha} \cdot I\!B^t_{g\alpha}  \cdot   G_{g\alpha\beta}
(56) T_{G\alpha\beta}  =   R_{s\alpha} \cdot I\!B^t_{o\alpha}  \cdot G_{o\alpha\beta} +  I\!B^t_{g\alpha}  \cdot   G_{g\alpha\beta}

(57) L_{W\alpha\beta} = I\!B^t_{w\alpha}  \cdot G_{w\alpha\beta} \cdot \delta p_{w\alpha\beta}
(58) L_{O\alpha\beta} = I\!B^t_{o\alpha}  \cdot   G_{o\alpha\beta} \cdot \delta p_{o\alpha\beta} \; + R_{v\alpha} \cdot I\!B^t_{g\alpha}  \cdot   G_{g\alpha\beta} \cdot \delta p_{g\alpha\beta}
(59) L_{G\alpha\beta} = R_{s\alpha} \cdot I\!B^t_{o\alpha}  \cdot G_{o\alpha\beta} \cdot \delta p_{o\alpha\beta} \; +  I\!B^t_{g\alpha}  \cdot   G_{g\alpha\beta} \cdot \delta p_{g\alpha\beta}

(60) \eta_{w\alpha\beta} = \left ( T_{w\alpha\beta} - T_{w\beta\alpha} \right)^{-1} \quad \text{if} \; |T_{w\alpha\beta} - T_{w\beta\alpha}| > \epsilon \quad \text{else} \; 0
(61) \eta_{o\alpha\beta} = \left ( T_{o\alpha\beta} - T_{o\beta\alpha} \right)^{-1} \quad \text{if} \; |T_{o\alpha\beta} - T_{o\beta\alpha}| > \epsilon \quad \text{else} \; 0
(62) \eta_{g\alpha\beta} = \left ( T_{g\alpha\beta} - T_{g\beta\alpha} \right)^{-1} \quad \text{if} \; |T_{g\alpha\beta} - T_{g\beta\alpha}| > \epsilon \quad \text{else} \; 0

Cross-Cell Face Pressure

(63) p^{t+1}_{w\alpha\beta} = \eta_{w\alpha\beta} \cdot \left( T_{w\alpha\beta} \cdot p_\alpha - T_{w\beta\alpha} \cdot p_\beta - L_{w\alpha\beta} + L_{w\beta\alpha} \right)
(64) p^{t+1}_{o\alpha\beta} = \eta_{o\alpha\beta} \cdot \left( T_{o\alpha\beta} \cdot p_\alpha - T_{o\beta\alpha} \cdot p_\beta - L_{o\alpha\beta} + L_{o\beta\alpha} \right)
(65) p^{t+1}_{g\alpha\beta} = \eta_{g\alpha\beta} \cdot \left( T_{g\alpha\beta} \cdot p_\alpha - T_{g\beta\alpha} \cdot p_\beta - L_{g\alpha\beta} + L_{g\beta\alpha} \right)

Cross-Cell Face Flux

(66) U^{t+1}_{W\alpha\beta} = T_{W\alpha\beta} \cdot \left( p^{t+1}_{w\alpha\beta} - p_\alpha \right) + L_{W\alpha\beta}
(67) U^{t+1}_{O\alpha\beta} =  T_{O\alpha\beta} \cdot \left( p^{t+1}_{o\alpha\beta} - p_\alpha \right) + L_{O\alpha\beta}
(68) U^{t+1}_{G\alpha\beta} =  T_{G\alpha\beta} \cdot \left( p^{t+1}_{g\alpha\beta} - p_\alpha \right) + L_{G\alpha\beta}

Cell Influx
(69) \delta I^{t+1}_{W \alpha} = \frac{\delta t}{V^0_{\phi_\alpha}}\cdot \left(\sum_{\beta\in\Gamma_{\alpha}}A_{\alpha\beta}\cdot U^{t+1}_{W\alpha\beta} \; + \, q^{t+1}_{W\alpha} \right)
(70) \delta I^{t+1}_{O \alpha} = \frac{\delta t}{V^0_{\phi_\alpha}}\cdot \left(\sum_{\beta\in\Gamma_{\alpha}}A_{\alpha\beta}\cdot U^{t+1}_{O\alpha\beta} \; + \, q^{t+1}_{O\alpha} \right)
(71) \delta I^{t+1}_{G \alpha} = \frac{\delta t}{V^0_{\phi_\alpha}}\cdot \left(\sum_{\beta\in\Gamma_{\alpha}}A_{\alpha\beta}\cdot U^{t+1}_{G\alpha\beta} \; + \, q^{t+1}_{G\alpha} \right)

Cell Fluid Balance


(72) I^{t+1}_{W \alpha} = I^t_{W \alpha} + \delta I^{t+1}_{W \alpha}
(73) I^{t+1}_{O \alpha} = I^t_{O \alpha} + \delta I^{t+1}_{O \alpha}
(74) I^{t+1}_{G \alpha} = I^t_{G \alpha} + \delta I^{t+1}_{G \alpha}

Handle Fluid Component Depletion

(75) \text{if} \; I^{t+1}_{W \alpha} < 0 \; \Rightarrow \; I^{t+1}_{W \alpha} = 0 \; , \; \; \delta I^{t+1}_{W \alpha} = - I^t_{W \alpha}
(76) \text{if} \; I^{t+1}_{O \alpha} < 0 \; \Rightarrow \; I^{t+1}_{O \alpha} = 0 \; , \; \; \delta I^{t+1}_{O \alpha} = - I^t_{O \alpha}
(77) \text{if} \; I^{t+1}_{G \alpha} < 0 \; \Rightarrow \; I^{t+1}_{O \alpha} = 0 \; , \; \; \delta I^{t+1}_{G \alpha} = - I^t_{G \alpha}

(78) \delta t^*_{W\alpha\beta^-} =\frac{-I_{W\alpha}^t\cdot V_{\phi_{\alpha}}^0-\delta t \cdot\sum_{\beta^+\in\Gamma^+_{\alpha}}A_{\alpha\beta^+} \cdot U^{t+1}_{W\alpha\beta^+}}{\sum_{\beta^-\in\Gamma^-_{\alpha}}A_{\alpha\beta^-}\cdot U^{t+1}_{W\alpha\beta^-} + q^{t+1}_{W\alpha}}
(79) \delta t^*_{O\alpha\beta^-} =\frac{-I_{O\alpha}^t\cdot V_{\phi_{\alpha}}^0-\delta t \cdot\sum_{\beta^+\in\Gamma^+_{\alpha}}A_{\alpha\beta^+} \cdot U^{t+1}_{O\alpha\beta^+}}{\sum_{\beta^-\in\Gamma^-_{\alpha}}A_{\alpha\beta^-}\cdot U^{t+1}_{O\alpha\beta^-} + q^{t+1}_{O\alpha}}
(80) \delta t^*_{G\alpha\beta^-} =\frac{-I_{G\alpha}^t\cdot V_{\phi_{\alpha}}^0-\delta t \cdot\sum_{\beta^+\in\Gamma^+_{\alpha}}A_{\alpha\beta^+} \cdot U^{t+1}_{G\alpha\beta^+}}{\sum_{\beta^-\in\Gamma^-_{\alpha}}A_{\alpha\beta^-}\cdot U^{t+1}_{G\alpha\beta^-} + q^{t+1}_{G\alpha}}

(81) \tilde q^{t+1}_{W\alpha} = q^{t+1}_{W\alpha} \cdot \delta t^*_{W\alpha\beta^-}/\delta t
(82) \tilde U^{t+1}_{W\alpha\beta^-} = U^{t+1}_{W\alpha\beta^-} \cdot \delta t^*_{W\alpha\beta^-}/\delta t
(83) \tilde U^{t+1}_{W\beta^-\alpha} = \tilde U^{t+1}_{W\alpha\beta^-}
(84) \tilde q^{t+1}_{O\alpha} = q^{t+1}_{O\alpha} \cdot \delta t^*_{O\alpha\beta^-}/\delta t
(85) \tilde U^{t+1}_{O\alpha\beta^-} = U^{t+1}_{O\alpha\beta^-} \cdot \delta t^*_{O\alpha\beta^-}/\delta t
(86) \tilde U^{t+1}_{O\beta^-\alpha} = \tilde U^{t+1}_{O\alpha\beta^-}
(87) \tilde q^{t+1}_{G\alpha} = q^{t+1}_{G\alpha} \cdot \delta t^*_{G\alpha\beta^-}/\delta t
(88) \tilde U^{t+1}_{G\alpha\beta^-} = U^{t+1}_{G\alpha\beta^-} \cdot \delta t^*_{G\alpha\beta^-}/\delta t
(89) \tilde U^{t+1}_{G\beta^-\alpha} = \tilde U^{t+1}_{G\alpha\beta^-}

 Reservoir Pressure

(90) \tilde B_w \left( p^{t+1}_\alpha + p_{cw}(s^t_\alpha) \right) \cdot I^{t+1}_{W\alpha} \, + \, \tilde B_o \left( p^{t+1}_\alpha + p_{co}(s^t_\alpha) \right) \cdot I^{t+1}_{O\alpha} \, + \, \tilde B_g \left( p^{t+1}_\alpha + p_{cg}(s^t_\alpha) \right) \cdot I^{t+1}_{G\alpha} - \exp \left( c_{\phi_\alpha}(p^{t+1}_\alpha) \cdot (p^{t+1}_\alpha - p^0_\alpha) \right) = 0
(91) p^{t+1}_{w\alpha} = p^{t+1}_\alpha + p_{cw}(s^t_\alpha)
(92) p^{t+1}_{o\alpha} = p^{t+1}_\alpha + p_{co}(s^t_\alpha)
(93) p^{t+1}_{g\alpha} = p^{t+1}_\alpha + p_{cg}(s^t_\alpha)


PVT properties
(94) B^{t+1}_{w\alpha} = B_w ( T^{t+1}_\alpha, \, p^{t+1}_{w\alpha})
(95) B^{t+1}_{o\alpha} = B_o ( T^{t+1}_\alpha, \, p^{t+1}_{o\alpha})
(96) B^{t+1}_{g\alpha} = B_g ( T^{t+1}_\alpha, \, p^{t+1}_{g\alpha})
(97) I\!B^{t+1}_{w\alpha} = \left[ B^{t+1}_{w\alpha} \right]^{-1}
(98) I\!B^{t+1}_{o\alpha} = \left[ B^{t+1}_{o\alpha} \right]^{-1}
(99) I\!B^{t+1}_{g\alpha} = \left[ B^{t+1}_{g\alpha} \right]^{-1}


(100) R^{t+1}_{v\alpha} = R_v(p^{t+1}_\alpha)
(101) R^{t+1}_{s\alpha} = R_s(p^{t+1}_\alpha)
(102) RR^{t+1}_{\alpha} =  1 - R^{t+1}_{v\alpha} \, R^{t+1}_{s\alpha}
(103) BB^{t+1}_{o\alpha} =  \frac{B^{t+1}_{o\alpha}}{RR^{t+1}_{\alpha}}
(104) BB^{t+1}_{g\alpha} =  \frac{B^{t+1}_{g\alpha}}{RR^{t+1}_{\alpha}}
(105) \tilde B^{t+1}_{w\alpha} = \tilde B_w (T^{t+1}_\alpha, p^{t+1}_{w\alpha})
(106) \tilde B^{t+1}_{o\alpha} = \tilde B_o (T^{t+1}_\alpha, p^{t+1}_{o\alpha})
(107) \tilde B^{t+1}_{g\alpha} = \tilde B_{g} (T^{t+1}_\alpha, p^{t+1}_{g\alpha})
Fluid Component Volumes
(108) V^{t+1}_{W\alpha} = V^0_{\phi\alpha} \cdot I^{t+1}_{W\alpha}
(109) V^{t+1}_{O\alpha} = V^0_{\phi\alpha} \cdot I^{t+1}_{O\alpha}
(110) V^{t+1}_{G\alpha} = V^0_{\phi\alpha} \cdot I^{t+1}_{G\alpha}

Reservoir Phase Volumes

(111) V^{t+1}_{w\alpha} = B_w(p^{t+1}_\alpha) \cdot V^{t+1}_{W\alpha}
(112) V^{t+1}_{o\alpha} = BB^{t+1}_{o\alpha} \cdot \left( \, V^{t+1}_{O\alpha} - R^{t+1}_{v\alpha} \cdot V^{t+1}_{G\alpha} \, \right)
(113) V^{t+1}_{g\alpha} = BB^{t+1}_{g\alpha} \cdot \left(\, V^{t+1}_{G\alpha} - R^{t+1}_{s\alpha} \cdot V^{t+1}_{O\alpha} \, \right)


(114) V^{t+1}_{\phi\alpha} = V^{t+1}_{w\alpha} + V^{t+1}_{o\alpha} + V^{t+1}_{g\alpha}

Reservoir Saturation

(115) s^{t+1}_{w\alpha} = \frac{V^{t+1}_{w\alpha}}{V^{t+1}_{\phi\alpha}}
(116) s^{t+1}_{o\alpha} = \frac{V^{t+1}_{o\alpha}}{V^{t+1}_{\phi\alpha}}
(117) s^{t+1}_{g\alpha} = \frac{V^{t+1}_{g\alpha}}{V^{t+1}_{\phi\alpha}}




See Also


Petroleum Industry / Upstream / Subsurface E&P Disciplines / Dynamic Flow Model Reservoir Flow Model (RFM) / Modified Black Oil Reservoir Flow @model / Modified Black Oil Reservoir Flow Grid Computation @model

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

Petroleum Industry / Upstream / Production / Subsurface Production / Well & Reservoir Management / Formation pressure / Multiphase formation pressure



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