Difference between revisions of "Midale water saturation and pore geometry"
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==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| | + | 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== | ||
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| − | + | [[File:Predicting-reservoir-system-quality-and-performance fig9-102.png|thumbnail|{{figure number|2}}.]] | |
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| + | 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. | ||
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| + | [[file:predicting-reservoir-system-quality-and-performance_fig9-104.png|thumb|{{figure number|3}}. Copyright: Coalson et al., 1994; courtesy RMAG.]] | ||
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| + | [[: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. | ||
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==See also== | ==See also== | ||
Revision as of 15:56, 5 February 2014
| Exploring for Oil and Gas Traps | |
| |
| Series | Treatise in Petroleum Geology |
|---|---|
| Part | Predicting the occurrence of oil and gas traps |
| Chapter | Predicting reservoir system quality and performance |
| Author | Dan J. Hartmann, Edward A. Beaumont |
| Link | Web page |
| Store | AAPG Store |
Log response and sw
Variations in pore geometry have the expected effect on log responses and water saturations (Sw). The Midale Vuggy in a cored field well consists of interbeds of packstone and mudstone. 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
As shown on 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 Sw. As a consequence, Sw values for mudstones are higher at any given elevation in the oil column.
Figure 3 is a Buckles plot for the Weyburn well. The hyperbolic curves represent equal values of Sw × Φ. Points from the same pore type that fall along a hyperbolic curve are at immobile Sw. Curves with higher values represent higher immobile Sw.
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
- Evaluation of trap type
- Weyburn field location and trap problem
- Middle lithofacies and distribution
- Midale porosity, pore geometries, and petrophysics
- Weyburn seal capacity
- Seal capacity and trap type
External links
| find literature about Midale water saturation and pore geometry |
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