Difference between revisions of "P/Z plot"
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| − | |title=P/Z plot | + | |title=P/Z plot to estimate reservoirs GIIP |
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|keywords=giip calculation, reservoir engineering, material balance, petroleum engineering | |keywords=giip calculation, reservoir engineering, material balance, petroleum engineering | ||
|description=P/Z plot is and quick and easy to use tool to estimate reservoirs GIIP. | |description=P/Z plot is and quick and easy to use tool to estimate reservoirs GIIP. | ||
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Revision as of 05:20, 8 November 2018
Brief
The P/Z plot is a plot of P/z versus Reservoir cumulative gas production, Gp.
The interpretation technique is fitting the data points with the straight line to estimate GIIP.
The P/Z plot is based on the Gas Material Balance equation.
Math & Physics
Applying Real Gas EOS at reservoir conditions:
(1)
Applying Real Gas EOS at standard conditions:
(2)
Dividing eq. 2 by eq. 1 and rearranging:
(3)
Applying eq. 3 for initial conditions and for any point in time:
Applying eq. 3 for any point in time:
Therefore at any time:
Or:
Thus a plot of P/z vs cumulative produced gas is a straight line intersecting X axis at GIIP.
Discussion
P/Z plot is a part of the Reservoir Management workflow in the E&P Portal used to estimate Reservoirs GIIP and recovery.
Example 1. Multiple Reservoirs on the same P/Z plot in the E&P Portal
Gas Flowing Material Balance is the more advanced tool to determine the Reservoirs GIIP and recovery as well as Well's EUR and JD.
Workflow
- Upload the data required
- Go to the Reservoir Management -> Performance Plots
- Select the Reservoirs you want to see and the Data range and click "Search"
- Scroll down the Performance Plots to see the P/Z plot
Data Required
- Create Field here
- Upload Wells
- Create or Upload Reservoirs here
- Upload Monthly Measures here
- Input the Reservoirs reserves and other data here
- Create or Upload PVT (SG, Pi, Ti) here
In case you need to calculate the Monthly Measures from the Daily Measures:
- Upload Wells
- Upload Daily Measures
- Calculate the Monthly Measures using Monthly Measures Calculator
Nomenclature
= gas initially in place, scf
= cumulative gas produced, scf
= reservoir pressure (changing), psia
= initial reservoir pressure (constant), psia
= pressure at standard conditions, psia
= initial reservoir temperature (constant), °R
= reservoir temperature (constant), °R
= temperature at standard conditions (constant), °R
= volume of gas in reservoir converted to standard conditions (changing), scf
= reservoir volume (constant), ft3
= gas compressibility factor (changing), dimensionless
= initial gas compressibility factor (constant), dimensionless
