The prospect of natural gas reservoir is broad. As the mining channel, the state of gas well determines the mining efficiency of the whole natural gas reservoir. After long-term mining of gas wells, the problem of water production will lead to the destruction of sand control screens, resulting in a large amount of sand production, which seriously endangers the safe production of gas wells. The “punched seam sleeves (PSS) + metal woven meshes (MWM)” is the main sand control structure, which failure mechanism needs to be explored. In this study, based on the erosion and corrosion environment, a simulation test with water content and gas production rate as single factor variables was designed. The dynamic grid layer laying method was used to simulate the corrosion environment, and the influence of erosion wear on sand control failure of screen pipe in water-bearing gas well under corrosive environment is analyzed. Through multi-factor comparison and evaluation, the structure of the screen pipe was optimized. The results show that when the water content increases from 0.5% to 7%, the maximum erosion rate of the PSS increases first and then decreases, reaching a maximum value of 5.341 × 10⁻⁵ kg/(m²·s) when the water content is 2%. The maximum erosion rate of MWM is linearly positively correlated with the water content. When the gas production rate increases from 3 to 10 m/s, the maximum erosion wear of defects increases from 5.108 × 10⁻⁷ to 1.247 × 10⁻⁵ kg/m², and the maximum erosion wear of MWM increases from 4.728 × 10⁻⁸ to 1.743 × 10⁻⁶ kg/m². Through orthogonal experimental analysis, it is found that the velocity has a significant effect on the erosion of the PSS. Based on this, the inlet and outlet flow channels of the screen pipe are optimized. The maximum erosion rate of the optimized PSS model is reduced by 25.7%, and the maximum erosion rate of MWM is reduced by 19.7%. The water-bearing gas well should properly control the mining speed at the initial stage of mining, and then increase after the formation of a stable sand bridge, and reduce the concentrated erosion caused by the drag force by optimizing the width of the inlet and outlet of the flow channel, which can effectively improve the service life of the screen pipe of the water-bearing gas well.

As an independent sand control unit or a common protective shell of a high-quality screen, the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas well. However, most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the screen. To explore the clogging mechanism of the punching screen, this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method (CFD-DEM) combined method. According to the combined motion of particles and fluids, the influence of the internal flow state on particle motion and accumulation was analyzed. The results showed that (1) the clogging process of the punching sand control unit is divided into three stages: initial clogging, aggravation of clogging and stability of clogging. In the initial stage of blockage, coarse particles form a loose bridge structure, and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control unit. In the stage of blockage intensification, the particle mass develops into a relatively complete sand bridge, which develops from both ends of the opening to the center of the opening. In the stable plugging stage, the sand deposits show a “fan shape” and form a “V-shaped” gully inside the punching slot element. (2) Under a certain reservoir particle-size distribution, The slit length and opening height have a large influence on the permeability and blockage rate, while the slit width size has little influence on the permeability and blockage rate. The microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study, which has some field guidance significance for the design of punching screen and sand prevention selection.