The paper presents a one-dimensional mathematical model of transient compressible thermal multi-component gas mixture flows in pipes. The set of the mass, momentum and enthalpy conservation equations is solved for gas phase in the model. Thermo-physical properties of multi-component gas mixture are calculated by solving the Equation of State (EOS) model. The Soave-Redlich-Kwong (SRK-EOS) model is chosen. Gas mixture viscosity is calculated on the basis of the Lee-Gonzales-Eakin (LGE) correlation. Numerical analysis on rapid decompression process in a shock tube having base natural gases is performed by using the proposed mathematical model. The model is successfully validated on the experimental measurements of the decompression wave speed in base natural gas mixtures. The proposed mathematical model shows a very good agreement with the experiments in a wide range of pressure values and predicts the decompression in base natural gases much better than analytical and mathematical models, which are available from the open source literature. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.