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===Petrophysical classification of carbonate pore space===

===Petrophysical classification of carbonate pore space===

The [[Archie classification]]<ref name=pt06r5>Archie, G. E., 1952, [http://archives.datapages.com/data/bulletns/1949-52/data/pg/0036/0002/0250/0278.htm Classification of carbonate reservoir rocks and petrophysical considerations]: AAPG Bulletin, v. 36, p. 278–298.</ref> was the first attempt at relating rock fabrics to petrophysical rock properties. [[Lucia classification|Lucia]]<ref name=pt06r79>Lucia, F. J., 1983, Petrophysical parameters estimated from visual descriptions of carbonate rocks—a field classification of carbonate pore space: Journal of Petroleum Technology, March, p. 629–637.</ref> improved on the Archie classification by defining the pore size distribution in relationship to the particle size and the spatial relationship of the pore space to the particles.

The [https://en.wikipedia.org/wiki/Archie's_law Archie classification]<ref name=pt06r5>Archie, G. E., 1952, [http://archives.datapages.com/data/bulletns/1949-52/data/pg/0036/0002/0250/0278.htm Classification of carbonate reservoir rocks and petrophysical considerations]: AAPG Bulletin, v. 36, p. 278–298.</ref> was the first attempt at relating rock fabrics to petrophysical rock properties. [[Lucia classification|Lucia]]<ref name=Lucia_1995>Lucia, F. J., 1995, [http://archives.datapages.com/data/bulletns/1994-96/data/pg/0079/0009/1250/1275.htm Rock-Fabric/Petrophysical Classification of Carbonate Pore Space for Reservoir Characterization]: AAPG Bulletin, v. 79, p. 1275-1300.</ref><ref name=pt06r79>Lucia, F. J., 1983, Petrophysical parameters estimated from visual descriptions of carbonate rocks—a field classification of carbonate pore space: Journal of Petroleum Technology, March, p. 629–637.</ref> improved on the Archie classification by defining the pore size distribution in relationship to the particle size and the spatial relationship of the pore space to the particles.

''[[Interparticle porosity]]''<ref name=pt06r79 /> is defined as that pore space located between grains ([[intergranular porosity]]) or between crystals ([[intercrystalline porosity]]), but which is not significantly larger than the grains or crystals. ''[[Vugular porosity|Vuggy porosity]]'' is defined as pore space larger than or within rock particles. Isolated [[vug]]s are called ''[[separate vug]]s'', while vugs that form a connected pore system on a reservoir scale are called ''[[touching vug]]s''.

''[[Interparticle porosity]]''<ref name=pt06r79 /> is defined as that pore space located between grains ([[intergranular porosity]]) or between crystals ([[intercrystalline porosity]]), but which is not significantly larger than the grains or crystals. ''[[Vugular porosity|Vuggy porosity]]'' is defined as pore space larger than or within rock particles. Isolated [[vug]]s are called ''[[separate vug]]s'', while vugs that form a connected pore system on a reservoir scale are called ''[[touching vug]]s''.

The geological [[reef]] model is a composite of the [[upward-shoaling]] [[subtidal]]-[[supratidal]] and [[karst]]-collapse reservoir models. The difference is that the [[facies tracts]] are compressed onto a carbonate [[shelf]] of limited areal extent with high relief above the seafloor and with steeply sloping sides. The [[interior shelf]] or [[lagoon]] facies ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]) located landward of the shelf edge normally contains a high percentage of mud. [[Grainstone]]s, [[packstone]]s, and [[boundstone]]s associated with the reef facies are typically found along the shelf edge.

The geological [[reef]] model is a composite of the [[upward-shoaling]] [[subtidal]]-[[supratidal]] and [[karst]]-collapse reservoir models. The difference is that the [[facies tracts]] are compressed onto a carbonate [[shelf]] of limited areal extent with high relief above the seafloor and with steeply sloping sides. The [[interior shelf]] or [[lagoon]] facies ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]) located landward of the shelf edge normally contains a high percentage of mud. [[Grainstone]]s, [[packstone]]s, and [[boundstone]]s associated with the reef facies are typically found along the shelf edge.

[[Reservoir quality#Compaction|]Compaction]] and [[Postaccumulation cementation|cementation]] typically destroy the permeability of the lagoonal muds, leaving the grain-dominated sediments and boundstones of the reef edge as reservoir rocks. However, selective [[leaching]], [[dolomitization]], and [[karst]]ing can significantly alter the [[permeability]] patterns, as discussed in previous sections. The reservoir flow units can be very complex due to the numerous possible combinations of depositional and [[Carbonate reservoir models: facies, diagenesis, and flow characterization#Diagenesis|diagenetic]] events.

[[Reservoir quality#Compaction|Compaction]] and [[Postaccumulation cementation|cementation]] typically destroy the permeability of the lagoonal muds, leaving the grain-dominated sediments and boundstones of the reef edge as reservoir rocks. However, selective [[leaching]], [[dolomitization]], and [[karst]]ing can significantly alter the [[permeability]] patterns, as discussed in previous sections. The reservoir flow units can be very complex due to the numerous possible combinations of depositional and [[Carbonate reservoir models: facies, diagenesis, and flow characterization#Diagenesis|diagenetic]] events.

==See also==

==See also==