Difference between revisions of "Mobility Ratio"

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==Example==
 
==Example==
 
Determine [[Mobility Ratio]] using the following data<ref name=DW/>:
 
Determine [[Mobility Ratio]] using the following data<ref name=DW/>:
 +
Core is 70% water and 30% oil saturation. Water phase permeability is 248 mD, oil phase permeability is 50 mD. Water viscosity is 1cP, oil viscosity is 3cP.
  
 
:<math> M = \frac{248/1}{50/3} =15 </math>
 
:<math> M = \frac{248/1}{50/3} =15 </math>

Revision as of 14:25, 25 March 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
:<math> \mu_o = oil viscosity, cP
 \mu_w = water viscosity, cP
 q_o = oil rate, cc/sec
 q_w = water rate, cc/sec

Example

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

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

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

See Also

References

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