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Pore and pore throat sizes (view source)
Revision as of 17:03, 31 January 2014
, 17:03, 31 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Predicting reservoir system quality and performance
| frompg = 9-1
| topg = 9-156
| author = Dan J. Hartmann, Edward A. Beaumont
| link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Pore and pore throat sizes have two defining parameters
* Absolute size
* Aspect ratio
==Absolute size==
Absolute size of a pore throat is the radius of a circle drawn perpendicular to fluid flow and fitting within its narrowest point. Absolute size of a pore is the radius of the largest sphere that will fit inside it. The cross-sectional shape of fluids moving through intergranular [[porosity]] is roughly circular. Both pores and pore throats can be divided into petrophysically significant size ranges.
==Measuring pore and pore throat sizes==
The figure below illustrates the concepts of pore size and pore throat size determined by measuring the radius of a sphere in the pore and the radius of a disk in the pore throat. Pore size can be estimated visually by using an SEM (scanning electron microscope), for example. Pore throat sizes for a rock can be measured using [[capillary pressure]]–mercury injection tests, which can be converted to a distribution or profile of pore throat sizes for a sample (see later sections in this chapter for more detailed discussions of pore throat size measurement). Erlich et al.<ref name=ch09r17>Erlich, R., Crabtree, S., J., Horkowitz, K., O., Horkowitz, J., P., 1991, Petrography and reservoir physics, 1: objective classification of reservoir porosity: AAPG Bulletin, vol. 75, no. 10, p. 1547–1563.</ref> describe a procedure for estimating pore and pore throat size from thin section image analysis.
[[file:predicting-reservoir-system-quality-and-performance_fig9-10.png|thumb|{{figure number|9-10}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
==Aspect ratio==
Aspect ratio is the ratio of pore size to pore throat size. Geometrical reasoning and limited experimental data suggest that aspect ratios have small ranges in intergranular and intercrystalline pore systems. Disparate Archie rock types such as quartz-cemented sandstones, bioturbated sandstones, and sucrosic dolomites have aspect ratios that range between 5:1 and 10:1. Non-Archie rock types have even larger variations in aspect ratios.
==See also==
* [[Classifying pore systems]]
* [[Pore system fundamentals]]
* [[Pore system shapes]]
* [[Connectivity and pore throat size]]
* [[Classifying pore systems]]
* [[Determining pore throat size from Pc curves]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Predicting reservoir system quality and performance]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Predicting reservoir system quality and performance
| frompg = 9-1
| topg = 9-156
| author = Dan J. Hartmann, Edward A. Beaumont
| link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Pore and pore throat sizes have two defining parameters
* Absolute size
* Aspect ratio
==Absolute size==
Absolute size of a pore throat is the radius of a circle drawn perpendicular to fluid flow and fitting within its narrowest point. Absolute size of a pore is the radius of the largest sphere that will fit inside it. The cross-sectional shape of fluids moving through intergranular [[porosity]] is roughly circular. Both pores and pore throats can be divided into petrophysically significant size ranges.
==Measuring pore and pore throat sizes==
The figure below illustrates the concepts of pore size and pore throat size determined by measuring the radius of a sphere in the pore and the radius of a disk in the pore throat. Pore size can be estimated visually by using an SEM (scanning electron microscope), for example. Pore throat sizes for a rock can be measured using [[capillary pressure]]–mercury injection tests, which can be converted to a distribution or profile of pore throat sizes for a sample (see later sections in this chapter for more detailed discussions of pore throat size measurement). Erlich et al.<ref name=ch09r17>Erlich, R., Crabtree, S., J., Horkowitz, K., O., Horkowitz, J., P., 1991, Petrography and reservoir physics, 1: objective classification of reservoir porosity: AAPG Bulletin, vol. 75, no. 10, p. 1547–1563.</ref> describe a procedure for estimating pore and pore throat size from thin section image analysis.
[[file:predicting-reservoir-system-quality-and-performance_fig9-10.png|thumb|{{figure number|9-10}}. Copyright: Coalson et al., 1994; courtesy RMAG.]]
==Aspect ratio==
Aspect ratio is the ratio of pore size to pore throat size. Geometrical reasoning and limited experimental data suggest that aspect ratios have small ranges in intergranular and intercrystalline pore systems. Disparate Archie rock types such as quartz-cemented sandstones, bioturbated sandstones, and sucrosic dolomites have aspect ratios that range between 5:1 and 10:1. Non-Archie rock types have even larger variations in aspect ratios.
==See also==
* [[Classifying pore systems]]
* [[Pore system fundamentals]]
* [[Pore system shapes]]
* [[Connectivity and pore throat size]]
* [[Classifying pore systems]]
* [[Determining pore throat size from Pc curves]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Predicting reservoir system quality and performance]]