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Line 25: − The diagram below shows relationships between relative permeability curves (drainage and imbibition), [[capillary pressure]], and fluid distribution in a homogeneous section of a reservoir system. The reservoir system rock has a [[porosity]] of 30% and a permeability of 10 md (r<sub>35</sub> = 1.1μ). Laboratory single-phase air permeability is typically used to represent absolute permeability (K<sub>a</sub> when determining relative permeability to oil or water at a specific S<sub>w</sub>. − + + + + + Line 37:
Line 40: − Figure 9-27 is an example of “drainage” relative permeability of a water-wet reservoir. It shows changes in K<sub>ro</sub> and K<sub>rw</sub> as S<sub>w</sub> decreases, as in a water-drive reservoir during hydrocarbon fill-up. “Imbibition” K<sub>ro</sub> and K<sub>rw</sub> have a different aspect, being measured while S<sub>w</sub> increases, as it does during production in a reservoir with a water drive.+ − − [[file:predicting-reservoir-system-quality-and-performance_fig9-27.png|thumb|{{figure number|9-27}}Modified.]]
Relative permeability (view source)
Revision as of 17:09, 19 February 2014
, 17:09, 19 February 2014→Interpreting a relative permeability curve
==Interpreting a relative permeability curve==
==Interpreting a relative permeability curve==
The figure below depicts three relative permeability curves:
[[file:predicting-reservoir-system-quality-and-performance_fig9-27.png|thumb|{{figure number|2}} Modified.]]
The diagram in [[:file:predicting-reservoir-system-quality-and-performance_fig9-27.png|Figure 2]] shows relationships between relative permeability curves (drainage and imbibition), [[capillary pressure]], and fluid distribution in a homogeneous section of a reservoir system. The reservoir system rock has a [[porosity]] of 30% and a permeability of 10 md (r<sub>35</sub> = 1.1μ). Laboratory single-phase air permeability is typically used to represent absolute permeability (K<sub>a</sub> when determining relative permeability to oil or water at a specific S<sub>w</sub>.
[[: [[:file:predicting-reservoir-system-quality-and-performance_fig9-27.png|Figure 2]] depicts three relative permeability curves:
* Water (K<sub>rw</sub>)—similar for both drainage and imbibition tests
* Water (K<sub>rw</sub>)—similar for both drainage and imbibition tests
Consider points A–D below. Point A, at S<sub>w</sub> = 100%, is the original condition of the sample. Here K<sub>rw</sub> ≈ K<sub>a</sub> (10 md). At point B (S<sub>w</sub> ≈ 90%, S<sub>0</sub> = 10%), oil breaks through the sample, representing the [[migration]] saturation of the sample; K<sub>ro</sub> = 1.0. At point C (S<sub>w</sub> ≈ 50%, S<sub>o</sub> ≈ 10%), K<sub>rw</sub> is less than 1% of K<sub>a</sub> and water, now confined to only the smallest ports, ceases to flow while oil flow approaches its maximum. At point D on the K<sub>ro-D</sub> curve (S<sub>w</sub> ≈ 20%, S<sub>o</sub> ≈ 80%), relative permeability is approaching 1.0 (~ 10 md).
Consider points A–D below. Point A, at S<sub>w</sub> = 100%, is the original condition of the sample. Here K<sub>rw</sub> ≈ K<sub>a</sub> (10 md). At point B (S<sub>w</sub> ≈ 90%, S<sub>0</sub> = 10%), oil breaks through the sample, representing the [[migration]] saturation of the sample; K<sub>ro</sub> = 1.0. At point C (S<sub>w</sub> ≈ 50%, S<sub>o</sub> ≈ 10%), K<sub>rw</sub> is less than 1% of K<sub>a</sub> and water, now confined to only the smallest ports, ceases to flow while oil flow approaches its maximum. At point D on the K<sub>ro-D</sub> curve (S<sub>w</sub> ≈ 20%, S<sub>o</sub> ≈ 80%), relative permeability is approaching 1.0 (~ 10 md).
[[:file:predicting-reservoir-system-quality-and-performance_fig9-27.png|Figure 2]] is an example of “drainage” relative permeability of a water-wet reservoir. It shows changes in K<sub>ro</sub> and K<sub>rw</sub> as S<sub>w</sub> decreases, as in a water-drive reservoir during hydrocarbon fill-up. “Imbibition” K<sub>ro</sub> and K<sub>rw</sub> have a different aspect, being measured while S<sub>w</sub> increases, as it does during production in a reservoir with a water drive.
==Drainage vs. imbibition curves==
==Drainage vs. imbibition curves==