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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 |
− | | frompg = 9-1 | + | | frompg = 9-23 |
− | | topg = 9-156 | + | | topg = 9-25 |
| | 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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| :<math>\mbox{P}_{\rm c} = \frac{2\gamma \cos \Theta}{\mbox{r}}</math> | | :<math>\mbox{P}_{\rm c} = \frac{2\gamma \cos \Theta}{\mbox{r}}</math> |
| | | |
− | This expression assumes the capillary phenomenon occurs within a tube with a circular cross section. Real pores only approximate this, and then only if they are intergranular or inter crystalline.<ref name=CoalsonPC>Coalson, personal communication, 1997</ref> | + | This expression assumes the capillary phenomenon occurs within a tube with a circular [[cross section]]. Real pores only approximate this, and then only if they are intergranular or inter crystalline.<ref name=CoalsonPC>Coalson, personal communication, 1997</ref> |
| | | |
| ==Capillary test procedure== | | ==Capillary test procedure== |
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| :<math>\mbox{r} = \frac{2\gamma \cos \Theta}{\mbox{P}_{\rm c}}</math> | | :<math>\mbox{r} = \frac{2\gamma \cos \Theta}{\mbox{P}_{\rm c}}</math> |
| | | |
− | Capillary pressure for a given S<sub>w</sub> can also be converted to an approximation of height above free water (''h'') within a reservoir system. From a capillary pressure curve at a given S<sub>w</sub>, we read the capillary pressure and multiply it by a factor that converts P<sub>c</sub> to [[buoyancy pressure]] (P<sub>b</sub>). If the conversion factor is not known, we use 0.4 for gas and 0.7 for oil. | + | Capillary pressure for a given S<sub>w</sub> can also be converted to an approximation of height above [[free water level|free water]] (''h'') within a reservoir system. From a capillary pressure curve at a given S<sub>w</sub>, we read the capillary pressure and multiply it by a factor that converts P<sub>c</sub> to [[buoyancy pressure]] (P<sub>b</sub>). If the conversion factor is not known, we use 0.4 for gas and 0.7 for oil. |
| | | |
| ==Using p<sub>c</sub> to estimate ''h'' and ''r''== | | ==Using p<sub>c</sub> to estimate ''h'' and ''r''== |
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| {| class = "wikitable" | | {| class = "wikitable" |
| |- | | |- |
− | ! To estimate | + | ! To estimate || Follow this procedure |
− | ! Follow this procedure
| |
| |- | | |- |
| | Pore throat size ( ''r'' ) from S<sub>w</sub> | | | Pore throat size ( ''r'' ) from S<sub>w</sub> |
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| [[file:predicting-reservoir-system-quality-and-performance_fig9-13.png|300px|thumb|{{figure number|3}}Example of a mercury capillary pressure test.]] | | [[file:predicting-reservoir-system-quality-and-performance_fig9-13.png|300px|thumb|{{figure number|3}}Example of a mercury capillary pressure test.]] |
| | | |
− | Using the curve in [[:file:predicting-reservoir-system-quality-and-performance_fig9-13.png|Figure 3]], if S<sub>w</sub> = 20% (point 1), then the mercury capillary pressure (P<sub>c</sub>) that must be overcome to enter pore throats at that point on the curve is [[pressure::200 psi]] (point 2). Converting mercury P<sub>c</sub> to hydrocarbon column height (''h''): | + | Using the curve in [[:file:predicting-reservoir-system-quality-and-performance_fig9-13.png|Figure 3]], if S<sub>w</sub> = 20% (point 1), then the mercury capillary pressure (P<sub>c</sub>) that must be overcome to enter pore throats at that point on the curve is [[pressure::200 psi]] (point 2). Converting mercury P<sub>c</sub> to [[hydrocarbon column]] height (''h''): |
| | | |
| :<math>\mbox{h} = 200 \mbox{ psi} \times 0.7 = 140 \mbox{ ft of oil column}</math> | | :<math>\mbox{h} = 200 \mbox{ psi} \times 0.7 = 140 \mbox{ ft of oil column}</math> |
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| * [[Pore system shapes]] | | * [[Pore system shapes]] |
| * [[Pore and pore throat sizes]] | | * [[Pore and pore throat sizes]] |
− | * [[Connectivity and pore throat size]] | + | * [[Pore throat size and connectivity]] |
| | | |
| ==References== | | ==References== |
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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]] |
| + | [[Category:Treatise Handbook 3]] |