Changes

==Nonreservoir pore geometry and pore type==

==Nonreservoir pore geometry and pore type==

[[file:predicting-reservoir-system-quality-and-performance_fig9-100.png|thumb|300px|{{figure number|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.