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Line 40: − [[: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.+ Line 79:
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==Interpreting a relative permeability curve==
==Interpreting a relative permeability curve==
[[file:predicting-reservoir-system-quality-and-performance_fig9-27.png|thumb|{{figure number|2}} Modified.]]
[[file:predicting-reservoir-system-quality-and-performance_fig9-27.png|thumb|{{figure number|2}} Modified from Arps.<ref name=Arps_1964>Arps, J. J. 1964, [http://archives.datapages.com/data/bulletns/1961-64/data/pg/0048/0002/0150/0157.htm Engineering concepts useful in oil finding]: AAPG Bulletin, v. 48, no. 2, p. 943-961.</ref>]]
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>.
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>.
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==
==See also==
==See also==
* [[Pore–fluid interaction]]
* [[Pore-fluid interaction]]
* [[Hydrocarbon expulsion, migration, and accumulation]]
* [[Hydrocarbon expulsion, migration, and accumulation]]
* [[Characterizing rock quality]]
* [[Characterizing rock quality]]
* [[Converting Pc curves to buoyancy, height, and pore throat radius]]
* [[Converting Pc curves to buoyancy, height, and pore throat radius]]
* [[What is permeability?]]
* [[What is permeability?]]
==References==
{{reflist}}
==External links==
==External links==