A macroscopic, mechanistic, and one-dimensional flow model is presented in this paper to calculate pressure and temperature profiles of gas production systems. The model＇s development is based on an average velocity between the inlet and outlet conditions of the pipe, and has been successfully applied to simulate the various types of pipe in gas production. A comparison between the results of this model and those produced by rigorous calculation has proved that the method is potentially powerful. A comprehensive heat transfer model is proposed to be used with this model. Tuning factors are introduced to match experimental pressure and/or temperature values. Diameter, length and overall heat transfer coefficient are the variables selected to tune.