Difference between revisions of "Mobility Ratio"

Revision as of 14:20, 25 March 2022

Mobility Ratio determines the relative rate of one fluid to another (etc. water to oil).

M \le 1

oil is dominant flowing phase, stable flow.

M > 1

water preferentially flows in the reservoir, unstable flow, fingering.

M = \frac{k_w/ \mu_w}{k_o/ \mu_o}=\frac{k_{rw}/ \mu_w}{k_{ro}/ \mu_o}=\frac{q_w B_w}{q_o B_o}

where^[1]

\mu_o

= oil viscosity, cP

\mu_w

= water viscosity, cP

B_o

= oil formation volume factor, m3/m3

B_w

= water formation volume factor, m3/m3

k_{rw}

= relative water phase permeability, function of the phase saturation, fraction

k_o

= oil phase permeability, function of the phase saturation, fraction

k_o

= relative oil phase permeability, function of the phase saturation, mD

k_w

= water phase permeability, function of the phase saturation, mD

q_o

= oil rate, cc/sec

q_w

= water rate, cc/sec

Dimensionless injected pore volume:

W_{iD} = \frac{W_i * B_{wi}}{PV} = \frac{W_i * B_{wi}}{A * h * \phi}

Injected movable pore volume:

MOPV_{inj} = \frac{W_i * B_{wi}}{MOPV} = \frac{W_i * B_{wi}}{A * h * \phi *(1-S_{wc}-S_{orw})}

where

S_{wc}

= Connate water saturation, fraction

S_{orw}

= Residual oil saturation to water, fraction

↑ Wolcott, Don (2009). Applied Waterflood Field Development. Houston: Energy Tribune Publishing Inc.

@@ Line 12: / Line 12: @@
 where<ref name=DW/>
-:<math> A </math> = Area, m2
+:<math> \mu_o </math> = oil viscosity, cP
-:<math> B_{wi} </math> = Injected water formation oil factor, m3/m3
+:<math> \mu_w </math> = water viscosity, cP
-:<math> h </math> = Net pay, oil saturated thickness, m
+:<math> B_o </math> = oil formation volume factor, m3/m3
-:<math> HCPV </math> = Hydrocarbon pore volume, m3
+:<math> B_w </math> = water formation volume factor, m3/m3
-:<math> HCPV_{inj} </math> = Injected hydrocarbon pore volumes, fraction
+:<math> k_{rw} </math> = relative water phase permeability, function of the phase saturation, fraction
-:<math> W_i </math> = Cumulative water injection volume, m3
+:<math> k_o </math> = oil phase permeability, function of the phase saturation, fraction
-:<math> \phi </math> = Porosity, fraction
+:<math> k_o </math> = relative oil phase permeability, function of the phase saturation, mD
-:<math> S_o </math> = Oil saturation, fraction
+:<math> k_w </math> = water phase permeability, function of the phase saturation, mD
+:<math> q_o </math> = oil rate, cc/sec
+:<math> q_w </math> = water rate, cc/sec
 ===Related definitions===