Difference between revisions of "Pore system shapes"

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{{merge|Pore systems}}
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{{publication  
 
{{publication  
 
  | image  = exploring-for-oil-and-gas-traps.png
 
  | image  = exploring-for-oil-and-gas-traps.png
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  | 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
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  | frompg  = 9-1
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  | frompg  = 9-19
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  | topg    = 9-156
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  | topg    = 9-19
 
  | 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
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==Archie and non-Archie rocks==
 
==Archie and non-Archie rocks==
  
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Choquette and Pray's<ref name=ch09r10>Choquette, P., W., Pray, L., C., 1970, [http://archives.datapages.com/data/bulletns/1968-70/data/pg/0054/0002/0200/0207.htm Geologic nomenclature and classification of porosity in sedimentary carbonates]: AAPG Bulletin, vol. 54, no. 2, p. 207–250. Classic reference for basic concepts regarding carbonate porosity.</ref> porosity types include two different groups of pore system shapes: petrophysically simple '''Archie porosity''' and petrophysically complex '''non-Archie porosity'''. In most cases, water saturation (S<sub>w</sub>) of rocks with Archie porosity can be predicted from log analysis using the [[Archie equation]]
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Choquette and Pray's<ref name=ch09r10>Choquette, P. W., and L. C. Pray, 1970, [http://archives.datapages.com/data/bulletns/1968-70/data/pg/0054/0002/0200/0207.htm Geologic nomenclature and classification of porosity in sedimentary carbonates]: AAPG Bulletin, vol. 54, no. 2, p. 207–250. Classic reference for basic concepts regarding carbonate porosity.</ref> porosity types include two different groups of pore system shapes: petrophysically simple '''Archie porosity''' and petrophysically complex '''non-Archie porosity'''. In most cases, water saturation (S<sub>w</sub>) of rocks with Archie porosity can be predicted from log analysis using the [[Archie equation]]
  
 
:<math>\mbox{S}_{\rm w} = \left(\frac{1}{\Phi^{\rm m}} \times \frac{\mbox{R}_{\rm w}}{\mbox{R}_{\rm t}}\right)^{\rm 1/n}</math>
 
:<math>\mbox{S}_{\rm w} = \left(\frac{1}{\Phi^{\rm m}} \times \frac{\mbox{R}_{\rm w}}{\mbox{R}_{\rm t}}\right)^{\rm 1/n}</math>
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where:
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* S<sub>w</sub> = water saturation of the uninvaded zone
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* n = saturation exponent, which varies from 1.8 to 4.0 but normally is 2.0
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* R<sub>w</sub> = formation water resistivity at formation temperature
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* Φ = [[porosity]]
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* m = cementation exponent, which varies from 1.7 to 3.0 but normally is 2.0
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* R<sub>t</sub> = true resistivity of the formation, corrected for invasion, borehole, thin bed, and other effects
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without modification. To predict water saturation in rocks with non-Archie porosity, we modify the Archie equation.
 
without modification. To predict water saturation in rocks with non-Archie porosity, we modify the Archie equation.
  
 
==Table of characteristics==
 
==Table of characteristics==
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The table below describes pore system shapes and other important characteristics of Archie and non-Archie rocks.<ref name=ch09r12>Coalson, E., B., Goolsby, S., M., Franklin, M., H., 1994, Subtle seals and fluid-flow barriers in carbonate rocks, in Dolson, J., C., Hendricks, M., L., Wescott, W., A., eds., Unconformity Related Hydrocarbons in Sedimentary Sequences: RMAG Guidebook for Petroleum Exploration and Exploitation in Clastic and Carbonate Sediments, p. 45–58.</ref>
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The table below describes pore system shapes and other important characteristics of Archie and non-Archie rocks.<ref name=ch09r12>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>
  
 
{| class = "wikitable"
 
{| class = "wikitable"
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| Mold-like  
 
| Mold-like  
 
*  Intraparticle  
 
*  Intraparticle  
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*  Moldic  
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*  [[Moldic]]
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*  Shelter
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*  [[Shelter]]
 
|-
 
|-
 
| rowspan=2 | Intercrystalline (found between angular particles)
 
| rowspan=2 | Intercrystalline (found between angular particles)
 
| Vug-like
 
| Vug-like
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*  Boring/burrow
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*  [[Bored or burrowed]]
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*  Growth-framework  
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*  [[Growth-framework]]
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*  Fenestral  
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*  [[Fenestral]]
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*  Vug/channel/cavern
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*  [[Vug]], [[channel]], [[cavern]]
 
|-
 
|-
 
| Fracture-like
 
| Fracture-like
 
*  [[Fracture]]
 
*  [[Fracture]]
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*  Shrinkage
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*  [[Shrinkage]]
 
|-
 
|-
 
| Relationship of pore shape to rock particles
 
| Relationship of pore shape to rock particles
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|-
 
|-
 
| [[Porosity]] reduction processes
 
| [[Porosity]] reduction processes
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| Grain coating or pore filling by calcite, silica, or dolomite
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| Grain coating or pore filling by [[calcite]], [[silica]], or [[dolomite]]
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| Pore or pore throat filling by clays or other minerals
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| Pore or pore throat filling by [[clay]]s or other minerals
 
|}
 
|}
  
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* [[Pore system fundamentals]]
 
* [[Pore system fundamentals]]
 
* [[Pore and pore throat sizes]]
 
* [[Pore and pore throat sizes]]
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* [[Connectivity and pore throat size]]
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* [[Pore throat size and connectivity]]
 
* [[Pore systems]]
 
* [[Pore systems]]
 
* [[Capillary pressure (Pc) curves: pore throat size determination]]
 
* [[Capillary pressure (Pc) curves: pore throat size determination]]
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[[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]]
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[[Category:Treatise Handbook 3]]

Latest revision as of 13:53, 4 April 2022

 It has been suggested that this article be merged with [[::Pore systems|Pore systems]]. (Discuss)
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

Archie and non-Archie rocks

Choquette and Pray's[1] porosity types include two different groups of pore system shapes: petrophysically simple Archie porosity and petrophysically complex non-Archie porosity. In most cases, water saturation (Sw) of rocks with Archie porosity can be predicted from log analysis using the Archie equation

where:

  • Sw = water saturation of the uninvaded zone
  • n = saturation exponent, which varies from 1.8 to 4.0 but normally is 2.0
  • Rw = formation water resistivity at formation temperature
  • Φ = porosity
  • m = cementation exponent, which varies from 1.7 to 3.0 but normally is 2.0
  • Rt = true resistivity of the formation, corrected for invasion, borehole, thin bed, and other effects


without modification. To predict water saturation in rocks with non-Archie porosity, we modify the Archie equation.

Table of characteristics

The table below describes pore system shapes and other important characteristics of Archie and non-Archie rocks.[2]

Feature Archie Non-Archie
Pore system shapes Intergranular (found between rounded particles); interparticle Mold-like
Intercrystalline (found between angular particles) Vug-like
Fracture-like
Relationship of pore shape to rock particles Negative image of particles making up matrix Relates only indirectly to particles making up matrix
Pore connectivity Pore throats connect pores into regular networks Pores are irregularly distributed and can be either poorly or very well connected
Porosity reduction processes Grain coating or pore filling by calcite, silica, or dolomite Pore or pore throat filling by clays or other minerals

See also

References

  1. ↑ Choquette, P. W., and L. C. Pray, 1970, Geologic nomenclature and classification of porosity in sedimentary carbonates: AAPG Bulletin, vol. 54, no. 2, p. 207–250. Classic reference for basic concepts regarding carbonate porosity.
  2. ↑ 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.

External links

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