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Line 16: − Variations in pore geometry have the expected effect on log responses and water saturations (S<sub>w</sub>). The Midale Vuggy in a cored field well consists of interbeds of packstone and mudstone. Below is a Pickett plot for the Midale Vuggy from an example well in Weyburn field. Data points cluster around higher resistivities for packstones (group A) and lower resistivities for mudstones (group B), reflecting the higher water saturations of the mudstones.+ − + − As shown on Figure 9-102, mudstones (B) are micro- to mesoporous; packstones (A) are meso- to macroporous. The mudstones have more pores with smaller pore throats than the packstones. This means mudstones have greater pore surface area and higher immobile S<sub>w</sub>. As a consequence, S<sub>w</sub> values for mudstones are higher at any given elevation in the oil column. − Following is a Buckles plot for the Weyburn well. The hyperbolic curves represent equal values of S<sub>w</sub> × Φ. Points from the same pore type that fall along a hyperbolic curve are at immobile S<sub>w</sub>. Curves with higher values represent higher immobile S<sub>w</sub>.+ + + + + + + − − [[file:predicting-reservoir-system-quality-and-performance_fig9-104.png|thumb|{{figure number|9-104}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
Midale water saturation and pore geometry (view source)
Revision as of 15:56, 5 February 2014
, 15:56, 5 February 2014no edit summary
==Log response and s<sub>w</sub>==
==Log response and s<sub>w</sub>==
[[file:predicting-reservoir-system-quality-and-performance_fig9-103.png|left|thumb|{{figure number|1}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
[[file:predicting-reservoir-system-quality-and-performance_fig9-103.png|thumb|{{figure number|9-103}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
Variations in pore geometry have the expected effect on log responses and water saturations (S<sub>w</sub>). The Midale Vuggy in a cored field well consists of interbeds of packstone and mudstone. [[:file:predicting-reservoir-system-quality-and-performance_fig9-103.png|Figure 1]] is a Pickett plot for the Midale Vuggy from an example well in Weyburn field. Data points cluster around higher resistivities for packstones (group A) and lower resistivities for mudstones (group B), reflecting the higher water saturations of the mudstones.
==Buckles plot==
==Buckles plot==
[[File:Predicting-reservoir-system-quality-and-performance fig9-102.png|thumbnail|{{figure number|2}}.]]
As shown on [[:File:Predicting-reservoir-system-quality-and-performance fig9-102.png|Figure 2]], mudstones (B) are micro- to mesoporous; packstones (A) are meso- to macroporous. The mudstones have more pores with smaller pore throats than the packstones. This means mudstones have greater pore surface area and higher immobile S<sub>w</sub>. As a consequence, S<sub>w</sub> values for mudstones are higher at any given elevation in the oil column.
[[file:predicting-reservoir-system-quality-and-performance_fig9-104.png|thumb|{{figure number|3}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
[[:file:predicting-reservoir-system-quality-and-performance_fig9-104.png|Figure 3]] is a Buckles plot for the Weyburn well. The hyperbolic curves represent equal values of S<sub>w</sub> × Φ. Points from the same pore type that fall along a hyperbolic curve are at immobile S<sub>w</sub>. Curves with higher values represent higher immobile S<sub>w</sub>.
On the plot, data for packstones (A), except for point 8, fall on a hyperbolic curve with a value between 100 and 300. This indicates these beds are at immobile water saturations. Point 8 is from a transition zone. Mudstones (B) also are at immobile water saturations but fall on a hyperbolic curve with higher numbers, between 1000 and 1300.
On the plot, data for packstones (A), except for point 8, fall on a hyperbolic curve with a value between 100 and 300. This indicates these beds are at immobile water saturations. Point 8 is from a transition zone. Mudstones (B) also are at immobile water saturations but fall on a hyperbolic curve with higher numbers, between 1000 and 1300.
==See also==
==See also==