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=== Tipe porositas geologis ===
;Porositas primer: porositasPorositas utama atau awal dari sistem porositas di dalam [[bebatuan]] atau deposit [[aluvial]].
;Porositas sekunder: porositasPorositas lanjutan atau terpisah dari sistem porositas di dalam bebatuan, umumnya meningkatkan porositas total bebatuan. Porositas ini dapat dihasilkan dari pelapukan kimiawi atau rekahan. Porositas sekunder dapat menggantikan porositas primer sepenuhnya atau mendampingi.
:Porositas rekahan: Porositas ini terkait dengan sistem rekahan atau patahan yang membentuk porositas sekunder yang dapat menjadi tempat penyimpanan reservoir.
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;Porositas ''vuggy'': Porositas sekunder yang dihasilkan dari pelarutan komponen besar yang terdapat di dalam bebatuan (seperti fosil dan material organik) dan meninggalkan lubang kecil sampai terciptanya [[gua]].
;Fracture porosity: This is porosity associated with a fracture system or faulting. This can create secondary porosity in rocks that otherwise would not be reservoirs for hydrocarbons due to their primary porosity being destroyed (for example due to depth of burial) or of a rock type not normally considered a reservoir (for example igneous intrusions or metasediments).
;[[Porositas efektif]] (disebut juga porositas terbuka): Fraksi dari volume total di mana aliran [[dinamika fluida|fluida dinamis]] dapat menempati ruang walau terdapat jalan buntu di dalamnya. Fluida dapat tetap mengalir karena variasi kondisi termal di dalamnya yang menyebabkan perubahan tekanan dan volume<ref>[http://www.epgeology.com/petrophysics-f11/what-the-difference-between-secondary-primary-porosity-t252.html Effective and Ineffective Porosity] at [http://www.epgeology.com/ E&P Geology.com]</ref> di dalam pori-pori yang terhubung.
;Vuggy porosity: This is secondary porosity generated by dissolution of large features (such as macrofossils) in [[carbonate rock]]s leaving large holes, [[vug]]s, or even [[cave]]s.
;Porositas inefektif (disebut juga porositas tertutup): Merupakan fraksi volume total di mana fluida atau gas ada di dalam namun tidak dapat mengalir.
;[[Effective porosity]] (also called ''open porosity''): Refers to the fraction of the total volume in which [[Fluid dynamics|fluid flow]] is effectively taking place and includes [[Caternary]] and [[Cul-de-sac|dead-end]] (as these pores cannot be flushed, but they can cause fluid movement by release of pressure like gas expansion<ref>[http://www.epgeology.com/petrophysics-f11/what-the-difference-between-secondary-primary-porosity-t252.html Effective and Ineffective Porosity] at [http://www.epgeology.com/ E&P Geology.com]</ref>) pores and excludes closed pores (or non-connected cavities). This is very important for groundwater and petroleum flow, as well as for solute transport.
;Porositas ganda: Merupakan ide konseptual di mana dua reservoir yang saling berhimpitan saling berinteraksi. Dalam akuifer bebatuan yang memiliki rekahan, massa bebatuan dan rekahan seringkali disimulasikan berhimpitan namun merupakan badan yang terpisah.
;Ineffective porosity (also called ''closed porosity''): Refers to the fraction of the total volume in which fluids or gases are present but in which [[Fluid dynamics|fluid flow]] can not effectively take place and includes the closed pores. Understanding the morphology of the porosity is thus very important for groundwater and petroleum flow.
;Porositas makro: Merujuk pada pori-pori yang berdiameter lebih besar dari 50 [[nanometer|nm]].
;Dual porosity: Refers to the conceptual idea that there are two overlapping reservoirs which interact. In fractured rock aquifers, the rock mass and fractures are often simulated as being two overlapping but distinct bodies. Delayed yield, and leaky aquifer flow solutions are both mathematically similar solutions to that obtained for dual porosity; in all three cases water comes from two mathematically different reservoirs (whether or not they are physically different).
;Porositas menengah: Pori-pori yang berukuran antara 2 nm sampai 50 nm.
;[[Macropore|Macro porosity]]: Refers to pores greater than 50 [[nanometer|nm]] in diameter. Flow through macropores is described by bulk diffusion.
;Porositas mikro: Pori-pori yang berukuran lebih kecil dari 2 nm.
;[[Mesoporous material|Meso porosity]]: Refers to pores greater than 2 nm and less than 50 nm in diameter. Flow through mesopores is described by Knudsen diffusion.
;[[Microporous material|Micro porosity]]: Refers to pores smaller than 2 nm in diameter. Movement in micropores is by activated diffusion.
== Porositas tekstil atau porositas aerodinamik ==
==Porosity of fabric or aerodynamic porosity==
Adalah rasio lubang yang dapat "dilalui oleh angin".
== Pengukuan porositas ==
The ratio of holes to solid that the wind "sees". Aerodynamic porosity is less than visual porosity, by an amount that depends on the constriction of holes.
[[Berkas:Porosity thin section GP.jpg|thumb|Metode optis dalah mengukur porositas bebatuan [[eolianite]] jaman [[Pleistocene]] dari [[pulau San Salvador]], Bahamas.]]
Beberapa metode dapat digunakan untuk mengukur porositas:
==Measuring porosity==
*Metode langsung dengan mengukur volume bahan curah dan lalu mengukur volume komponen per bagian. Hanya bisa dilakukan pada benda berukuran cukup besar dengan komponen individu tidak memiliki pori-pori.
[[File:Porosity thin section GP.jpg|thumb|Optical method of measuring porosity: [[thin section]] under gypsum plate shows porosity as purple color, contrasted with carbonate grains of other colors. [[Pleistocene]] [[eolianite]] from [[San Salvador Island]], Bahamas. Scale bar 500 microns.]]
*Metode optis dengan menggunakan mikroskop.<ref name="Dul"/>
Several methods can be employed to measure porosity:
*Metode tomografi komputer, menggunakan pemindaian CT untuk membuat pencitraan tiga dimensi dari geometri eksternal dan internal, termasuk ruang kosong di dalamnya.
* Direct methods (determining the bulk volume of the porous sample, and then determining the volume of the skeletal material with no pores (pore volume = total volume - material volume).
*[[Imbibisi]] yaitu menenggelamkan bahan berpori ke dalam fluida yang dilakukan di dalam ruang vakum.<ref name="Dul"/> Fluida yang dipilih adalah fluida yang mampu membasahi bahan secara mendalam dan tidka bereaksi dengan bahan.
* Optical methods (e.g., determining the area of the material versus the area of the pores visible under the microscope). The "areal" and "volumetric" porosities are equal for porous media with random structure.<ref name="Dul"/>
*Metode pengurapan air
* Computed tomography method (using [[industrial CT scanning]] to create a 3D rendering of external and internal geometry, including voids. Then implementing a defect analysis utilizing computer software)
*Intrusi raksa
* [[Imbibition]] methods,<ref name="Dul"/> i.e., immersion of the porous sample, under vacuum, in a fluid that preferentially wets the pores.
* Metode Gasekspansi expansion methodgas.<ref name="Dul">F.A.L. Dullien, "Porous Media. Fluid Transport and Pore Structure", [[Academic Press]], 1992.</ref> <!--A sample of known bulk volume is enclosed in a container of known volume. It is connected to another container with a known volume which is evacuated (i.e., near vacuum pressure). When a valve connecting the two containers is opened, gas passes from the first container to the second until a uniform pressure distribution is attained. Using [[ideal gas]] law, the volume of the pores is calculated as ▼** Water saturation method (pore volume = total volume of water - volume of water left after soaking).
* Water evaporation method (pore volume = (weight of saturated sample - weight of dried sample)/density of water)
* Mercury intrusion [[porosimetry]] (several non-mercury intrusion techniques have been developed due to toxicological concerns, and the fact that mercury tends to form amalgams with several metals and alloys).
▲* Gas expansion method.<ref name="Dul">F.A.L. Dullien, "Porous Media. Fluid Transport and Pore Structure", [[Academic Press]], 1992.</ref> A sample of known bulk volume is enclosed in a container of known volume. It is connected to another container with a known volume which is evacuated (i.e., near vacuum pressure). When a valve connecting the two containers is opened, gas passes from the first container to the second until a uniform pressure distribution is attained. Using [[ideal gas]] law, the volume of the pores is calculated as
:<math>V_V = V_T-V_a-V_b {P_2 \over {P_2-P_1}}</math>,
where
}}</ref>
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==See also==
* [[Petrofisik]]
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