Study on pressure fluctuation characteristics in sand-plugging wellbore using the Euler-moment method

Pressure fluctuations caused by sand-plugging during the fracturing process can hinder the displacement of fracturing fluid and reduce the effectiveness of reservoir stimulation. Existing wellbore multiphase flow models struggle to account for the transient distribution states of particles of various sizes, limiting our understanding of wellbore pressure behavior post-sand-plugging. This paper introduces a one-dimensional flow solver based on the one-dimensional Euler-moment method. This model considers the rates of aggregation and fragmentation of solid particles, various initial particle distribution concentrations, and solves for the time-varying particle distribution state and wellbore pressure field during sand-plugging. By analyzing characteristic quantities during pressure fluctuations, we find that the pressure at any well depth oscillates with consistent periods, and the amplitude of these fluctuations increases with well depth. As the initial particle concentration increases, the increase in pressure values and fluctuation amplitude decreases, while the area under the pressure curve and the attenuation rate of pressure amplitude along the well depth increases. The average pressure amplitude decay rate is 0.39 MPa/s over time and 0.52 MPa/m along well depth, with the pressure wave propagating at an average speed of 1289 m/s. This study provides a theoretical reference for early warning and control of sand-plugging conditions.