A discussion on the transient inflow performance relationship curve of gas-water well

Gas-water well is commonly found in the middle-late stage of water-carrying gas reservoir development. At this time, the flow characteristics of gas and water in formation are different from those of single-phase gas, thus inevitably causing that the characteristics of pressure performance (or inflow performance) of gas-water well are distinct from those of net-gas well. The inflow performance of gas-water well is the fundament of performance analysis and wellbore lifting. The research on inflow performance of gas-water well in this paper is a good try and relevant report hasn't been found in domestic and foreign literatures. On the basis of the principle of mass conservation, a mathematical model of gas-water two-phase transient flow in formation was set up and it was linearized through defining gas-water two-phase pseudo-pressure function. After achieving the solution of the mathematical model, a binomial productivity equation of gas-water well with two-phase flow in formation was derived in consideration of the influence of formation damage and non-Darcy effect, thus establishing the theory of transient inflow performance relationship curve of gas-water well. Based on this, the transient inflow performance relationship curve of gas-water well may be drawn up and a theoretical fundament is provided for the performance analysis of gas-water well.