Difference between revisions of "Hydrocarbon pressure gradient: plotting"
Jump to navigation
Jump to search
Cwhitehurst (talk | contribs) |
Cwhitehurst (talk | contribs) |
||
Line 6: | Line 6: | ||
| part = Critical elements of the petroleum system | | part = Critical elements of the petroleum system | ||
| chapter = Formation fluid pressure and its application | | chapter = Formation fluid pressure and its application | ||
− | | frompg = 5- | + | | frompg = 5-26 |
− | | topg = 5- | + | | topg = 5-26 |
| author = Edward A. Beaumont, Forrest Fiedler | | author = Edward A. Beaumont, Forrest Fiedler | ||
| link = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm | | link = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm |
Revision as of 14:41, 13 February 2015
Exploring for Oil and Gas Traps | |
Series | Treatise in Petroleum Geology |
---|---|
Part | Critical elements of the petroleum system |
Chapter | Formation fluid pressure and its application |
Author | Edward A. Beaumont, Forrest Fiedler |
Link | Web page |
Store | AAPG Store |
We can estimate the downdip free-water level from a valid fluid pressure measured within a reservoir.
Plotting gradient
The list below outlines the procedure for plotting a hydrocarbon pressure gradient on a hydrostatic pressure plot when a measured pressure is available from the reservoir.
- Plot measured fluid pressure on a hydrostatic pressure–depth plot.
- Determine the hydrocarbon pressure gradient from one of two ways:
- Measured hydrocarbon density
- Estimates of hydrocarbon density
- Determine the buoyancy pressure gradient: static water pressure gradient minus hydrocarbon pressure gradient.
- Determine a pressure above or below the measured depth point. The table below lists the steps for determining this number.
- Pick a depth above or below the measured point.
- Multiply the difference in depth by the buoyancy pressure gradient.
- 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 pressure::3530 psi and buoyancy pressure gradient is 0.076 psi/ft. What is the hydrocarbon pressure at depth::7507 ft?
- Solution:
- 7607 ft – 7507 ft = 100 ft
- 100 ft × 0.076 psi/ft = 7.6 psi
- Hydrocarbon pressure at depth::7507 ft = pressure::3530 psi – pressure::7.6 psi = pressure::3522.4 psi
- 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.
See also
- Static hydrocarbon pressure gradients
- Estimating static oil pressure gradients
- Estimating static gas pressure gradients
- Free water level determination using pressure