Optimization of Tubing and Pump Installation Parameters of Fractured Horizontal Wells in Shale Gas Reservoirs: Method and Case study

Abstract Shale gas wells often experience severe wellbore liquid accumulation during mid-to-late production period, leading to a sharp decline in gas production rate as the capacity of liquid-carrying decreases. Installing tubing or pumps can effectively mitigate these losses. However, how to determine the timing and depth of tubing or pump installation remains challenging due to variations in liquid loading along the horizontal wellbore. To fill this gap, an integrated transient multiphase flow model was established coupling the wellbore and reservoir to optimization of tubing and pump installation parameters of fractured horizontal wells in shale gas reservoirs. Three production scenarios are simulated, including casing production, tubing production, and pump-assisted production. History matching results show that the bottom-hole pressure, liquid production rates, and gas production rates match well. Besides, too early installation of tubing may reduce gas productivity significantly. Installing pump as soon as liquid loading occurs in a shale gas well can enhance its liquid-carrying capacity, thereby increasing cumulative gas production rates. Compared to installation on 60th or 160th day, installing the pump on 80th day yields better performance and increases cumulative gas production rates. Besides, pump-assisted production increased cumulative gas production by 16.5% compared to tubing production, and by 20.5% compared to casing production. This study provides a theoretical basis for optimizing the placement location and timing of pump installation in shale gas wells, aimed at reducing production losses due to liquid loading.