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added Category:Treatise Handbook 3 using HotCat
| 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
| frompg = 9-1
| frompg = 9-38
| topg = 9-156
| topg = 9-39
| 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
==Horizontal and vertical k<sub>a</sub>==
==Horizontal and vertical k<sub>a</sub>==
Horizontal K<sub>a</sub> (i.e., parallel to bedding) is generally greater than vertical K<sub>a</sub> (i.e., normal to bedding) because of vertical changes in sorting and because of bedding laminations. High vertical K<sub>a</sub> generally results from fracturing or even burrowing that cuts across bedding. Most K<sub>a</sub> calculations are made from measurements of horizontal plugs.
Horizontal K<sub>a</sub> (i.e., parallel to bedding) is generally greater than vertical K<sub>a</sub> (i.e., normal to bedding) because of vertical changes in [[Core_description#Maturity|sorting]] and because of bedding laminations. High vertical K<sub>a</sub> generally results from fracturing or even burrowing that cuts across bedding. Most K<sub>a</sub> calculations are made from measurements of horizontal plugs.
==Steady-state permeability equation==
==Steady-state permeability equation==
[[file:predicting-reservoir-system-quality-and-performance_fig9-24.png|300px|thumb|{{figure number|1}}See text for explanation.]]
[[file:predicting-reservoir-system-quality-and-performance_fig9-24.png|300px|thumb|{{figure number|1}}Illustration of variables.]]
[[Permeability]] is not measured; it is calculated. The steady-state equation for calculating permeability (using an integrated form of Darcy's law) is
[[Permeability]] is not measured; it is calculated. The steady-state equation for calculating permeability (using an integrated form of Darcy's law) is
* P<sub>1</sub> = pressure at input end, atm
* P<sub>1</sub> = pressure at input end, atm
* P<sub>2</sub> = pressure at output end, atm
* P<sub>2</sub> = pressure at output end, atm
* μ = air viscosity, cp
* μ = air [[viscosity]], cp
The diagram of a plug in [[:file:predicting-reservoir-system-quality-and-performance_fig9-24.png|Figure 1]] illustrates some of these variables.
The diagram of a plug in [[:file:predicting-reservoir-system-quality-and-performance_fig9-24.png|Figure 1]] illustrates some of these variables.
==Example==
==Example==
[[file:predicting-reservoir-system-quality-and-performance_fig9-25.png|300px|thumb|{{figure number|2}}See text for explanation.]]
[[file:predicting-reservoir-system-quality-and-performance_fig9-25.png|400px|thumb|{{figure number|2}}Two flow units.]]
In [[:file:predicting-reservoir-system-quality-and-performance_fig9-25.png|Figure 2]], flow unit 1 is a sucrosic dolomite. On a face of a plug of flow unit 1, a very large number of very small pore throats (capillaries) occur, resulting in a measurable flow (Q). That Q, at a measured cross-sectional area A of the plug, yields a K<sub>a</sub> of approximately 20 md.
In [[:file:predicting-reservoir-system-quality-and-performance_fig9-25.png|Figure 2]], flow unit 1 is a sucrosic [[dolomite]]. On a face of a plug of flow unit 1, a very large number of very small pore throats (capillaries) occur, resulting in a measurable flow (Q). That Q, at a measured cross-sectional area A of the plug, yields a K<sub>a</sub> of approximately 20 md.
The sample from flow unit 2 with the same A has fewer, larger pore throats (capillaries) exposed in the face of the plug. If the Q for flow unit 2 is slightly lower than flow unit 1, then the K<sub>a</sub> will be lower (by using the same A).
The sample from flow unit 2 with the same A has fewer, larger pore throats (capillaries) exposed in the face of the plug. If the Q for flow unit 2 is slightly lower than flow unit 1, then the K<sub>a</sub> will be lower (by using the same A).
[[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]]
[[Category:Treatise Handbook 3]]