Abstract: The paper A Discussion about A New Model for Forecasting Production of Oil and Gas Fields ("A Discussion" for short) written by Xu Yi and Du Ying presented that some errors in math principle exist in Wang-Li's model for production forecast, resulting in the groundless model and the unreliable case-study results. However, "A Discussion" had not proposed the reasons and arguments for negating the Wang-Li's model except for three questions in it. This paper makes in-depth theoretical analysis and applied verification of this model structure, and further indicates that the math principle for the Wang-Li's model is correct, its structure is also precise. When the integral limit of the model t=0, Np0≠0; when the constant C>-1, the incredible results do not appear at all.

Key words: model, production rate, recoverable reserve, prediction, forecast