Difference between revisions of "Mobility Ratio"

Latest revision as of 09:02, 4 April 2022

Brief

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.

Equation

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

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

M

= mobility ratio, fraction

\mu_o

= oil viscosity, cP

\mu_w

= water viscosity, cP

q_o

= oil rate, cc/sec

q_w

= water rate, cc/sec

Rule of thumb:

M = 0.333 \mu_o

Example

Determine the Mobility Ratio using the following data^[1]:
Core is at 70% water and 30% oil saturation. Water phase permeability is 248 mD, oil phase permeability is 50 mD. Water viscosity is 1 cP, oil viscosity is 3 cP.

M = \frac{248/1}{50/3} =15

In this case the mobility of water is 15 times higher than the mobility of water.

References

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

[DW-1] Wolcott, Don (2009). Applied Waterflood Field Development. Houston: Energy Tribune Publishing Inc.

[1]

@@ Line 7: / Line 7: @@
 :<math> M > 1</math> water preferentially flows in the reservoir, unstable flow, fingering.
-===Equation===
+==Equation==
 :<math> 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}</math>
-where<ref name=DW/>
+where
-:<math> A </math> = Area, m2
+:<math> B_o </math> = oil formation volume factor, m3/m3
-:<math> B_{wi} </math> = Injected water formation oil factor, m3/m3
+:<math> B_w </math> = water formation volume factor, m3/m3
-:<math> h </math> = Net pay, oil saturated thickness, m
+:<math> k_{rw} </math> = relative water phase permeability, function of the phase saturation, fraction
-:<math> HCPV </math> = Hydrocarbon pore volume, m3
+:<math> k_o </math> = oil phase permeability, function of the phase saturation, fraction
-:<math> HCPV_{inj} </math> = Injected hydrocarbon pore volumes, fraction
+:<math> k_o </math> = relative oil phase permeability, function of the phase saturation, mD
-:<math> W_i </math> = Cumulative water injection volume, m3
+:<math> k_w </math> = water phase permeability, function of the phase saturation, mD
-:<math> \phi </math> = Porosity, fraction
+:<math> M </math>= mobility ratio, fraction
-:<math> S_o </math> = Oil saturation, fraction
+:<math> \mu_o </math> = oil viscosity, cP
+:<math> \mu_w </math> = water viscosity, cP
+:<math> q_o </math> = oil rate, cc/sec
+:<math> q_w </math> = water rate, cc/sec
-===Related definitions===
+Rule of thumb:
-Dimensionless injected pore volume:
+:<math> M = 0.333 \mu_o</math>
-:<math> W_{iD} = \frac{W_i * B_{wi}}{PV} = \frac{W_i * B_{wi}}{A * h * \phi}</math>
-Injected movable pore volume:
+==Example==
-:<math> MOPV_{inj} = \frac{W_i * B_{wi}}{MOPV} = \frac{W_i * B_{wi}}{A * h * \phi *(1-S_{wc}-S_{orw})}</math>
+Determine the [[Mobility Ratio]] using the following data<ref name=DW/>:<BR>
+Core is at 70% water and 30% oil saturation. Water phase permeability is 248 mD, oil phase permeability is 50 mD. Water viscosity is 1 cP, oil viscosity is 3 cP.
-where
+:<math> M = \frac{248/1}{50/3} =15 </math>
-:<math> S_{wc} </math> = Connate water saturation, fraction
+In this case the mobility of water is 15 times higher than the mobility of water.
-:<math> S_{orw} </math> = Residual oil saturation to water, fraction
 ==See Also==

Navigation menu

Navigation

Categories

Products