Abstract: Analysis of twoOphase flow of gas and water in wellbore/reservoir has important significance for natural gas exploitation.During the production , natural gas always flows from reservoir to wellbore. But , the numerical simulations in the past , which generally omitted some inner relations between reservoir and wellbore , respectively. This method cannot precisely describe the change of physical state in whole system. In the paper , we
combine transient twoOphase model of gas and water in wellbore with nonhomogeneous multiphase seepage model in reservoir to discuss the problem of well test . The combined model considers mutual action between wellbore and reservoir. In computation ,the discrete simultaneous equations are solved. The numerical results show that the method can effectively reflect various physical phenomena in well test .

Key words: Combined reservoir/ wellbore model, gas water twoOphase flow, numerical simulation, finite volume method