Changes

  | part    = Critical Elements of the Trap

  | part    = Critical Elements of the Trap

  | chapter = Predicting reservoir system quality and performance

  | chapter = Predicting reservoir system quality and performance

  | frompg  = 9-1

  | frompg  = 9-20

  | topg    = 9-156

  | topg    = 9-20

  | 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

[[file:predicting-reservoir-system-quality-and-performance_fig9-10.png|thumb|300px|{{figure number|1}}From Coalson et al.<ref name=Coalsonetal_1994>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: Rocky Mountain Association of Geologists guidebook for petroleum exploration and exploitation in clastic and carbonate sediments, p. 45-58.</ref> Courtesy RMAG.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-10.png|thumb|300px|{{figure number|1}}From Coalson et al.<ref name=Coalsonetal_1994>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: Rocky Mountain Association of Geologists guidebook for petroleum exploration and exploitation in clastic and carbonate sediments, p. 45-58.</ref> Courtesy RMAG.]]

[[:file:predicting-reservoir-system-quality-and-performance_fig9-10.png|Figure 1]] 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 microscopy (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. Erlich et al.<ref name=ch09r17>Erlich, R., Crabtree, S., J., Horkowitz, K., O., Horkowitz, J., P., 1991, [http://archives.datapages.com/data/bulletns/1990-91/data/pg/0075/0010/0000/1547.htm 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 analysis|thin section image analysis]].

[[:file:predicting-reservoir-system-quality-and-performance_fig9-10.png|Figure 1]] 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 microscopy (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. Erlich et al.<ref name=ch09r17>Erlich, R., S. J. Crabtree, K. O. Horkowitz, and J. P. Horkowitz, 1991, [http://archives.datapages.com/data/bulletns/1990-91/data/pg/0075/0010/0000/1547.htm 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 analysis|thin section image analysis]].

==Aspect ratio==

==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 (see [[Reservoir quality]]). Disparate Archie rock types such as quartz-cemented sandstones, [[Bioturbation|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.

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]] (see [[Reservoir quality]]). Disparate Archie rock types such as quartz-cemented sandstones, [[Bioturbation|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==

==See also==

* [[Pore system fundamentals]]

* [[Pore system fundamentals]]

* [[Pore system shapes]]

* [[Pore system shapes]]

* [[Connectivity and pore throat size]]

* [[Pore throat size and connectivity]]

* [[Capillary pressure (Pc) curves: pore throat size determination]]

* [[Capillary pressure (Pc) curves: pore throat size determination]]

[[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]]