Abstract: With the help of the singlewell numerical simulator of the numerical simulation software,the single gaswell models of productivity decline for both abnormal and normal pressure gas wells are established,and the gaswell productivity decline data for both abnormal and normal pressure gas wells are obtained.Based on these productivity data and combined with two kinds of automatic matching model,the decline parameters,k_gh,k_g/Φ,and OGIP for both abnormal and normal pressure gas wells can be determined.Meanwhile,in this article,a way of acquiring the formation parameters by firstly removing the unsteady productivity data and then by following the automatic matching model is adopted,which can improve the predication precision,and the calculation results are justified with the touchstones of these two models respectively.The calculation results show that the two models are in good agreement with those of numerical simulation.

Key words: numerical simulation, productivity decline, automatic matching, pseudo steady state