Difference between revisions of "Relative Permeability"

From wiki.pengtools.com
Jump to: navigation, search
(Example)
Line 38: Line 38:
 
Same core at 70% water and 30% oil and qw=0.332 cc/sec and qo=0.0184 cc/sec:
 
Same core at 70% water and 30% oil and qw=0.332 cc/sec and qo=0.0184 cc/sec:
  
:<math> k_w = \frac{0.332*1*1*3}{2*2} = 0.249 D = 249 mD </math>
+
:<math> k_w(S_w=0.7)= \frac{0.332*1*1*3}{2*2} = 0.249 D = 249 mD </math>
:<math> k_o = \frac{0.0184*1.2*3*3}{2*2} = 0.049 D = 50 mD </math>
+
:<math> k_o(S_w=0.7)= \frac{0.0184*1.2*3*3}{2*2} = 0.049 D = 50 mD </math>
  
  

Revision as of 16:46, 30 March 2022

Brief

Relative Permeability is the ratio of the effective permeability to base oil permeability measured at connate water saturation[1].

 k_{ro} = k_o/k_{oS_{wc}}
 k_{rw} = k_w/k_{oS_{wc}}

where

 k_{ro} = Oil relative permeability, fraction
 k_{rw} = Water relative permeability, fraction
 k_o = Effective water permeability, mD
 k_w = Effective water permeability, mD
 k_{oS_{wc}} = Effective oil permeability at irreducible oil saturation, mD
 S_{wc} = Connate water saturation, fraction

Related definitions

Effective permeability - oil, water, gas phase permeability when more than one phase is present. Depends on fluids saturations.

Absolute permeability - permeability of the core sample when saturated with one liquid. Independent of fluid. Dependent on pore throat sizes.

Example

Determine the Relative Permeability using the following data[1]:
Core dimensions: A=2 cm2, L=3 cm. PVT: water viscosity = 1 cP, oil viscosity = 3 cP, Bw=1 cc/cc, Bo=1.2 cc/cc.

Core is at 100% water and qw=0.553 cc/sec:

Using Darcy's law:

 k_{abs} = \frac{0.553*1*1*3}{2*2} = 0.415 D = 415 mD

Same core at 100% oil and qo=0.154 cc/sec:

 k_{abs} = \frac{0.154*1.2*3*3}{2*2} = 0.415 D = 415 mD

Same core at 70% water and 30% oil and qw=0.332 cc/sec and qo=0.0184 cc/sec:

 k_w(S_w=0.7)= \frac{0.332*1*1*3}{2*2} = 0.249 D = 249 mD
 k_o(S_w=0.7)= \frac{0.0184*1.2*3*3}{2*2} = 0.049 D = 50 mD


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

See Also

References

  1. Jump up to: 1.0 1.1 Wolcott, Don (2009). Applied Waterflood Field DevelopmentPaid subscription required. Houston: Energy Tribune Publishing Inc.