Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Predicting reservoir system quality and performance

  | chapter = Predicting reservoir system quality and performance

  | frompg  = 9-1

  | frompg  = 9-142

  | topg    = 9-156

  | topg    = 9-143

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

==Reservoir character==

==Reservoir character==

[[file:predicting-reservoir-system-quality-and-performance_fig9-102.png|300px|thumb|{{figure number|1}}Crossplot of routine core porosity and permeability from Midale in an example well at Weyburn field. Copyright: Coalson et al.;<ref name=Coalson1994>Coalson, E. B., S. M. Goolsby, and M. H. Franklin, 1994, Subtle seals and fluid-flow barriers in carbonate rocks, in J. C. Dolson, M. L. Hendricks, and W. A. Wescott, eds., Unconformity Related Hydrocarbons in Sedimentary Sequences: RMAG Guidebook for Petroleum Exploration and Exploitation in Clastic and Carbonate Sediments, p. 45–58.</ref> courtesy RMAG.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-102.png|300px|thumb|{{figure number|1}}Crossplot of routine core porosity and permeability from the Midale in an example well at Weyburn field. Copyright: Coalson et al.;<ref name=Coalson1994>Coalson, E. B., S. M. Goolsby, and M. H. Franklin, 1994, Subtle seals and fluid-flow barriers in carbonate rocks, in J. C. Dolson, M. L. Hendricks, and W. A. Wescott, eds., Unconformity Related Hydrocarbons in Sedimentary Sequences: RMAG Guidebook for Petroleum Exploration and Exploitation in Clastic and Carbonate Sediments, p. 45–58.</ref> courtesy RMAG.]]

Good reservoir properties are seen in the vuggy packstone facies, congruent with the observed pore geometries. Permeabilities in rock with only 10% porosity are as high as 10 md.

Good reservoir properties are seen in the vuggy packstone facies, congruent with the observed pore geometries. Permeabilities in rock with only 10% porosity are as high as 10 md.

[[:file:predicting-reservoir-system-quality-and-performance_fig9-102.png|Figure 1]] is a crossplot of routine core [[porosity]] and [[permeability]] from Midale in an example well at Weyburn field. The diagonal lines are contours of equal [[Characterizing_rock_quality#What_is_r35.3F|r₃₅]] values. On the plot, vuggy packstone facies (group A; data points 3, 4, 6, and 8) are characterized by lower porosity but higher permeability.

[[:file:predicting-reservoir-system-quality-and-performance_fig9-102.png|Figure 1]] is a crossplot of routine core [[porosity]] and [[permeability]] from the Midale in an example well at Weyburn field. The diagonal lines are contours of equal [[Characterizing_rock_quality#What_is_r35.3F|r₃₅]] values. On the plot, vuggy packstone facies (group A; data points 3, 4, 6, and 8) are characterized by lower porosity but higher permeability.

==Nonreservoir pore geometry and pore type==

==Nonreservoir pore geometry and pore type==

[[file:predicting-reservoir-system-quality-and-performance_fig9-100.png|Figure 2]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-100.png|thumb|300px|{{figure number|2}}Petrophysical characteristics of the main nonreservoir facies in the field: lime and dolomite mudstones to wackestones.]]

In contrast to the [http://www.merriam-webster.com/dictionary/vug vuggy] [[packstone]] facies, the porous [[mudstone]] facies displays poor [[permeability]] (5 md or less), even though porosity can be as high as 30% (points 1 and 5, group B in [[:file:predicting-reservoir-system-quality-and-performance_fig9-102.png|Figure 1]]). This is because the porosity is pinpoint vugs isolated within fine intercrystalline [[Wikipedia:Mesoporous material|meso]]- to [[Wikipedia:Microporous material|microporosity]] formed by silt-sized (10μ or less) dolomite rhombs. [[Capillary pressure]] and [[Scanning electron microscopy (SEM)|SEM]] data indicate the pore throats are less than 1μ in radius, with an abundance of pore throats about 0.5μ in radius or smaller (see [[file:predicting-reservoir-system-quality-and-performance_fig9-100.png|Figure 2]]). Port size puts much of this rock in micropore type. While localized lenses of porous mudstone have as much as 30% porosity and 20 md permeability, these probably are laterally isolated from each other.

In contrast to the [http://www.merriam-webster.com/dictionary/vug vuggy] [[packstone]] facies, the porous [[mudstone]] facies displays poor [[permeability]] (5 md or less), even though porosity can be as high as 30% (points 1 and 5, group B in [[:file:predicting-reservoir-system-quality-and-performance_fig9-102.png|Figure 1]]). This is because the porosity is pinpoint vugs isolated within fine intercrystalline [[Wikipedia:Mesoporous material|meso]]- to [[Wikipedia:Microporous material|microporosity]] formed by silt-sized (10μ or less) [[dolomite]] rhombs. [[Capillary pressure]] and [[Scanning electron microscopy (SEM)|SEM]] data indicate the pore throats are less than 1μ in radius, with an abundance of pore throats about 0.5μ in radius or smaller (see [[:file:predicting-reservoir-system-quality-and-performance_fig9-100.png|Figure 2]]). Port size puts much of this rock in micropore type. While localized lenses of porous mudstone have as much as 30% porosity and 20 md permeability, these probably are laterally isolated from each other.

==See also==

==See also==

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting reservoir system quality and performance]]

[[Category:Predicting reservoir system quality and performance]]