
SI

English

Notes

Q  leakage rate

m3/min

scf/min

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

C  unit conversion factor

2840

35.37

Note the coefficient for SI units is different from API RP14B. 14B is
low by
a factor of 100 based on the specified units.

P  pressure

MPa

psi

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

z  gas deviation factor



The technique used by this program was developed by Dranchuk, Purvis and Robinson.
The BenedictWebbRubin equation of state was fit to the Z factor surface defined
by the StandingKatz Z factor correlation. The resulting nonlinear equation is
solved for Z as a function of reduced temperature and pressure using NewtonRaphson
iteration.

t  buildup time

minutes

minutes


V  volume, amount of gas space

m3

ft3

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.

T  temperature

C 
F

Range is 20F to 300F
Note: the inputs for the program are in C or F. The program converts to absolute
values.





Note: the following are used by the program to calculate the z factors.

Gas Gravity



Default value of gas gravity is .6 (air = 1.0).
Gas gravity must be between 0.55
and 1.10.

CO2



Range is 080%.
The sum of CO2, H2S and N2 must be less than 100%.
The sum of CO2
and H2S must be less than 80%

H2S



Range is 080%.

N2



Range is 0100%.




