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  = 9-144

  | topg    = 9-156

  | topg    = 9-144

  | 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

==Log response and S_w==

==Log response and S_w==

Variations in pore geometry have the expected effect on log responses and [[water saturation]]s (S_w). 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 construction|Pickett plot]] for the Midale Vuggy from an example well in Weyburn field. Data points cluster around higher [[Basic_open_hole_tools#Resistivity|resistivities]] for packstones (group A) and lower resistivities for mudstones (group B), reflecting the higher water saturations of the mudstones.

Variations in pore geometry have the expected effect on log responses and [[water saturation]]s (S_w). The Midale vuggy beds in a cored field well consist of interbeds of [[packstone]] and [[mudstone]]. [[:file:predicting-reservoir-system-quality-and-performance_fig9-103.png|Figure 1]] is a [[Pickett plot construction|Pickett plot]] for the Midale vuggy beds from an example well in Weyburn field. Data points cluster around higher [[Basic_open_hole_tools#Resistivity|resistivities]] for packstones (group A) and lower resistivities for mudstones (group B), reflecting the higher water saturations of the mudstones.

==Buckles plot==

==Buckles plot==

<gallery mode=packed heights=200px widths=200x>

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predicting-reservoir-system-quality-and-performance_fig9-103.png|{{figure number|1}}Pickett plot for the Midale Vuggy from an example well in 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.

predicting-reservoir-system-quality-and-performance_fig9-103.png|{{figure number|1}}Pickett plot for the Midale vuggy beds from an example well in 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.

Predicting-reservoir-system-quality-and-performance fig9-102.png|{{figure number|2}}Illustration of (A) mudstones that are  meso- to macroporous and (B) micro- to mesoporous packstones. From Coalson et al.;<ref name=Coalson1994 /> courtesy RMAG.

Predicting-reservoir-system-quality-and-performance fig9-102.png|{{figure number|2}}Illustration of (A) packstones that are  meso- to macroporous and (B) micro- to mesoporous mudstones. From Coalson et al.;<ref name=Coalson1994 /> courtesy RMAG.

predicting-reservoir-system-quality-and-performance_fig9-104.png|{{figure number|3}}Buckles plot for the Weyburn well. Copyright: Coalson et al.;<ref name=Coalson1994 /> courtesy RMAG.

predicting-reservoir-system-quality-and-performance_fig9-104.png|{{figure number|3}}Buckles plot for the Weyburn well. Copyright: Coalson et al.;<ref name=Coalson1994 /> courtesy RMAG.

</gallery>

</gallery>

As shown on [[:File:Predicting-reservoir-system-quality-and-performance fig9-102.png|Figure 2]], mudstones (A) are micro- to mesoporous; packstones (B) are [[Wikipedia:Mesoporous material|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_w. As a consequence, S_w values for mudstones are higher at any given elevation in the oil column.

As shown on [[:File:Predicting-reservoir-system-quality-and-performance fig9-102.png|Figure 2]], mudstones (B) are [[Wikipedia:Microporous material|micro]]- to [[Wikipedia:Mesoporous material|mesoporous]]; packstones (A) are meso- to [http://en.wiktionary.org/wiki/macroporous 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_w. As a consequence, S_w values for mudstones are higher at any given elevation in the oil column.

[[: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_w × Φ. Points from the same pore type that fall along a hyperbolic curve are at immobile S_w. Curves with higher values represent higher immobile S_w.

[[: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_w × porosity (Φ). Points from the same pore type that fall along a hyperbolic curve are at immobile S_w. Curves with higher values represent higher immobile S_w.

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 [http://petrowiki.org/Glossary%3AIrreducible_water_saturation immobile (irreducible) 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==

[[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]]