Difference between revisions of "Hydrocarbon column: calculation of maximum height"

From AAPG Wiki
Jump to navigation Jump to search
(Initial import)
 
Line 15: Line 15:
 
}}
 
}}
 
==Calculation==
 
==Calculation==
 
+
The maximum column of hydrocarbons that can accumulate under a seal occurs when ''P''<sub>b</sub> equals ''P''<sub>d</sub>. If ''P''<sub>b</sub> exceeds ''P''<sub>d</sub>, the hydrocarbons will leak through the seal. If ''P''<sub>b</sub> is less than ''P''<sub>d</sub>, it would be possible to seal a greater column of hydrocarbons.
The maximum column of hydrocarbons that can accumulate under a seal occurs when P<sub>b</sub> equals P<sub>d</sub>. If P<sub>b</sub> exceeds P<sub>d</sub>, the hydrocarbons will leak through the seal. If P<sub>b</sub> is less than P<sub>d</sub>, it would be possible to seal a greater column of hydrocarbons.
 
  
 
Therefore, for the maximum hydrocarbon column
 
Therefore, for the maximum hydrocarbon column
  
:<math>\mbox{P}_{\rm b}  = \mbox{P}_{\rm d}</math>
+
:<math>P_{\rm b}  = P_{\rm d}</math>
:<math>(\rho_{\rm w} - \rho_{\rm h}) \mbox{gh} &= \frac{2\gamma \cos \theta}{\mbox{R}}\\\mbox{h} &= \frac{\left(\displaystyle\frac{2\gamma \cos \theta}{\mbox{R}}\right)}{(\rho_{\rm w} - \rho_{\rm h})}\mbox{g}</math>
+
:<math>(\rho_{\rm w} - \rho_{\rm h}) \mbox{g} h = \frac{2\gamma \cos \theta}R</math>
 +
:<math>h = \frac{\left(\displaystyle\frac{2\gamma \cos \theta} R \right)}{(\rho_{\rm w} - \rho_{\rm h})\mbox{g}}</math>
  
 
or, in mixed units,
 
or, in mixed units,
  
:<math>\mbox{h} = \left(\frac{\mbox{P}_{\rm d}}{\rho_{\rm w} - \rho_{\rm h}}\right) 0.433</math>
+
:<math>h = \left(\frac{P_{\rm d}}{\rho_{\rm w} - \rho_{\rm h}}\right) 0.433</math>
  
 
where:
 
where:
  
* h = height of the hydrocarbon [[length::( ft]])
+
* ''h'' = height of the hydrocarbon [ft]
  
 
==Effect on seal capacity==
 
==Effect on seal capacity==

Revision as of 16:49, 31 January 2014

Exploring for Oil and Gas Traps
Series Treatise in Petroleum Geology
Part Predicting the occurrence of oil and gas traps
Chapter Evaluating top and fault seal
Author Grant M. Skerlec
Link Web page
Store AAPG Store

Calculation[edit]

The maximum column of hydrocarbons that can accumulate under a seal occurs when Pb equals Pd. If Pb exceeds Pd, the hydrocarbons will leak through the seal. If Pb is less than Pd, it would be possible to seal a greater column of hydrocarbons.

Therefore, for the maximum hydrocarbon column

or, in mixed units,

where:

  • h = height of the hydrocarbon [ft]

Effect on seal capacity[edit]

The height of the hydrocarbon column (h) in the above equations is a theoretical maximum. The actual height is less because of the effect of the reservoir. If the reservoir itself had zero displacement pressure, the height of the hydrocarbon column would attain the theoretical maximum and the OWC would coincide with the free water level. If the reservoir has some displacement pressure greater than zero, then the height of the hydrocarbon column is less than the theoretical maximum, or

where:

  • Pds = displacement pressure of the seal
  • Pdr = displacement pressure of the reservoir

See also[edit]

External links[edit]

find literature about
Hydrocarbon column: calculation of maximum height
Datapages button.png GeoScienceWorld button.png OnePetro button.png Google button.png