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SI
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English
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Notes
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Q - leakage rate
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m3/min
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scf/min
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Allowable leak rate (API 14B, appendix E)
SI units: .43 m3/min, or 400 cm3/min
liquid
English units: 15 scf/min, or 13.5 oz/min
liquid
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C - unit conversion factor
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2840
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35.37
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Note the coefficient for SI units is different from API RP14B. 14B is
low by
a factor of 100 based on the specified units.
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P - pressure
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MPa
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psi
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Range is 0 psig to 10,000 psig.
Note: the final pressure must be great than or equal
to the initial pressure.
Note: 1 MPa = 10 bar = 1,000,000 Pa
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z - gas deviation factor
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The technique used by this program was developed by Dranchuk, Purvis and Robinson.
The Benedict-Webb-Rubin equation of state was fit to the Z factor surface defined
by the Standing-Katz Z factor correlation. The resulting non-linear equation is
solved for Z as a function of reduced temperature and pressure using Newton-Raphson
iteration.
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t - build-up time
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minutes
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minutes
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V - volume, amount of gas space
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m3
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ft3
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In deepwater applications, the SSSV may be closed, then the tubing above the SSV
partially loaded with Methanol to reduce the volume to be pressured and reduce the
test length. The volume in this case is the remaining gas volume after the methanol
has been pumped into the well.
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T - temperature
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C |
F
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Range is -20F to 300F
Note: the inputs for the program are in C or F. The program converts to absolute
values.
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Note: the following are used by the program to calculate the z factors.
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Gas Gravity
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Default value of gas gravity is .6 (air = 1.0).
Gas gravity must be between 0.55
and 1.10.
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CO2
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Range is 0-80%.
The sum of CO2, H2S and N2 must be less than 100%.
The sum of CO2
and H2S must be less than 80%
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H2S
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Range is 0-80%.
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N2
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Range is 0-100%.
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