الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Combining the continuity equation, the momentum equation and the equation-of-state yields the general equation that describes the real gas flow in porous media. This generalized equation is non-linear and can be solved only by numerical techniques. However, by applying a few simplifying assumptions, the flow equation can be partially linearized. The resulting equation is still non-linear due to the variation of pressure-dependent physical properties, viscosity and super-compressibility factor. To take this variation into account, the pioneers introduced the real gas pseudo-pressure notation. To apply real gas pseudo-pressure based solutions of the real gas diffusivity equation, reservoir pressures are converted to their complementary real gas pseudo-pressures and vice versa. Four techniques are used for real gas pseudo-pressure/pressure conversion, namely, numerical integration, table look up and interpolation, curve fitting, and analytical integration. The error increases as the pressure segment increases for numerical integration technique, inherent accuracy problems with double interpolation between pseudo-reduced pressure and pseudoreduced temperature values for table lookup and interpolation technique, the accuracy depends on the regression tool and the correlations used to generate the data points and no published correlation incorporated both pressure and temperature for curve fitting technique and the analytical integration is complicated and time consuming especially when incorporated in gas simulators. To overcome the shortage of the previous techniques, this work introduces a simple generalized dimensionless polynomial correlation that can be used for real gas pressure/pseudo-pressure conversion. The correlation was developed using polynomial regression analysis. It covers a wide range of reservoir pressures (up to 10000 psia) and reservoir temperatures (up to 460 oF). It is applied for sweet dry and wet gas reservoirs contaminated with minor amounts of non-hydrocarbon impurities. The proposed correlation was verified by comparison with previous techniques that are used for real gas pseudo-pressure estimation and showed 5.09 % average value of the average absolute relative error for seven cases and by application to gas well testing which showed comparable results for six cases. The correlation was also verified using gas reservoir simulation. The analytical solution of the real gas diffusivity equation using the proposed correlation and Klins and Biterge model were compared with the results of GASSIM and showed comparable results for two cases. Finally, a one-dimensional gas simulator was developed in MATLAB code to show how the proposed correlation can minimize the time of simulation dramatically when it is incorporated in gas simulators.