Abstract: In the middle or late period of a gas reservoir by horizontal well development process, the flow resistance may increase sharply due to producing water, and the gas flow theory of single phase isn't fit for two-phase flow of gas and water, anymore. This paper proposes composite model method to analyze the horizontal gas well productivity when producing water. It means that the near-well-bore permeability should decrease for the effect of produced water, while the permeability far from the well keeps the same. Also, this paper studies the effect of water on horizontal gas well productivity through building the productivity equation.

Key words: horizontal gas well, producing water, productivity, equation