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Hydrocarbon pressure gradient: plotting (view source)
Revision as of 21:27, 29 January 2014
, 21:27, 29 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Critical elements of the petroleum system
| chapter = Formation fluid pressure and its application
| frompg = 5-1
| topg = 5-64
| author = Edward A. Beaumont, Forrest Fiedler
| link = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
We can estimate the downdip free-water level from a valid fluid pressure measured within a reservoir.
==Plotting gradient==
The table below outlines the procedure for plotting a hydrocarbon pressure gradient on a hydrostatic pressure plot when a measured pressure is available from the reservoir.
{| class = "wikitable"
|-
! Step
! Action
|-
| 1
| Plot measured fluid pressure on a hydrostatic pressure–depth plot.
|-
| 2
| Determine the hydrocarbon pressure gradient from one of two ways:
* Measured hydrocarbon density * Estimates of hydrocarbon density
|-
| 3
| Determine the buoyancy pressure gradient: static water pressure gradient minus hydrocarbon pressure gradient.
|-
| 4
| Determine a pressure above or below the measured depth point. The table below lists the steps for determining this number.
* <table-wrap id="ch05utbl16a" position="float"> <table frame="hsides"> <colgroup> <col align="center"></col> <col align="left"></col> </colgroup> <thead> <tr> <th align="center"> Step </th> <th align="center"> Action </th> </tr> </thead> <tbody> <tr> <td align="center"> 1 Pick a depth above or below the measured point. </td></tr> <tr> 2 Multiply the difference in depth by the buoyancy pressure gradient. </tr> <tr> 3 Add the number from step 2 to the measured pressure if the depth is deeper; subtract if shallower. </tr> </tbody> </table> </table-wrap>
|-
| <th align="center"> Step</th>
| <th align="center"> Action</th>
|-
| 1
| Pick a depth above or below the measured point.
|-
| 2
| Multiply the difference in depth by the buoyancy pressure gradient.
|-
| 3
| Add the number from step 2 to the measured pressure if the depth is deeper; subtract if shallower.
|}
'''Example:'''
Measured pressure at [[depth::7607 ft]] is 3530 psi and buoyancy pressure gradient is 0.076 psi/ft. What is the hydrocarbon pressure at 7507 ft?
'''Solution:'''
7607 – 7507 = 100 ft
100 ft × 0.076 psi/ft = 7.6 psi
Hydrocarbon pressure at [[depth::7507 ft]] = 3530 psi – 7.6 psi = 3522.4 psi
<tr><td align="center">5</td><td align="left">Plot the pressure number from step 4 on the pressure–depth plot and draw a line between this point and the measured pressure point. This line is the hydrocarbon pressure gradient.</td></tr>
==See also==
* [[Static hydrocarbon pressure gradients]]
* [[Estimating static oil pressure gradients]]
* [[Estimating static gas pressure gradients]]
* [[Finding free-water level using pressure]]
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Critical elements of the petroleum system]]
[[Category:Formation fluid pressure and its application]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Critical elements of the petroleum system
| chapter = Formation fluid pressure and its application
| frompg = 5-1
| topg = 5-64
| author = Edward A. Beaumont, Forrest Fiedler
| link = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
We can estimate the downdip free-water level from a valid fluid pressure measured within a reservoir.
==Plotting gradient==
The table below outlines the procedure for plotting a hydrocarbon pressure gradient on a hydrostatic pressure plot when a measured pressure is available from the reservoir.
{| class = "wikitable"
|-
! Step
! Action
|-
| 1
| Plot measured fluid pressure on a hydrostatic pressure–depth plot.
|-
| 2
| Determine the hydrocarbon pressure gradient from one of two ways:
* Measured hydrocarbon density * Estimates of hydrocarbon density
|-
| 3
| Determine the buoyancy pressure gradient: static water pressure gradient minus hydrocarbon pressure gradient.
|-
| 4
| Determine a pressure above or below the measured depth point. The table below lists the steps for determining this number.
* <table-wrap id="ch05utbl16a" position="float"> <table frame="hsides"> <colgroup> <col align="center"></col> <col align="left"></col> </colgroup> <thead> <tr> <th align="center"> Step </th> <th align="center"> Action </th> </tr> </thead> <tbody> <tr> <td align="center"> 1 Pick a depth above or below the measured point. </td></tr> <tr> 2 Multiply the difference in depth by the buoyancy pressure gradient. </tr> <tr> 3 Add the number from step 2 to the measured pressure if the depth is deeper; subtract if shallower. </tr> </tbody> </table> </table-wrap>
|-
| <th align="center"> Step</th>
| <th align="center"> Action</th>
|-
| 1
| Pick a depth above or below the measured point.
|-
| 2
| Multiply the difference in depth by the buoyancy pressure gradient.
|-
| 3
| Add the number from step 2 to the measured pressure if the depth is deeper; subtract if shallower.
|}
'''Example:'''
Measured pressure at [[depth::7607 ft]] is 3530 psi and buoyancy pressure gradient is 0.076 psi/ft. What is the hydrocarbon pressure at 7507 ft?
'''Solution:'''
7607 – 7507 = 100 ft
100 ft × 0.076 psi/ft = 7.6 psi
Hydrocarbon pressure at [[depth::7507 ft]] = 3530 psi – 7.6 psi = 3522.4 psi
<tr><td align="center">5</td><td align="left">Plot the pressure number from step 4 on the pressure–depth plot and draw a line between this point and the measured pressure point. This line is the hydrocarbon pressure gradient.</td></tr>
==See also==
* [[Static hydrocarbon pressure gradients]]
* [[Estimating static oil pressure gradients]]
* [[Estimating static gas pressure gradients]]
* [[Finding free-water level using pressure]]
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Critical elements of the petroleum system]]
[[Category:Formation fluid pressure and its application]]