Difference between revisions of "Mobility Ratio"

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:<math> M > 1</math> water preferentially flows in the reservoir, unstable flow, fingering.
 
:<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>
 
:<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>
  

Revision as of 17:35, 2 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

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.

See Also

References

  1. Jump up Wolcott, Don (2009). Applied Waterflood Field DevelopmentPaid subscription required. Houston: Energy Tribune Publishing Inc.