Applying the DPM numerical simulation method to predict the erosion life of metal mesh screen in gas wells

In the production process of deepwater gas well, high-velocity fluid carries reservoir sand grains to erode the screen, which is likely to result in sand control failure of the screen. At present, the laboratory coupon erosion experiment only considers the factors of the mesh, so the error of the predicted screen erosion life is larger. In this paper, a 3D numerical simulation model for the full structure of metal mesh screen was established by taking the metal mesh screen commonly used for sand control of gas well as the research object. The flow and erosion process of sand grains in the screen was simulated by means of the discrete particle flow method (DPM), the influences of sand grains on the velocity distribution and erosion rate of metal mesh at different fluid velocities and concentrations were analyzed, and the erosion life of metal mesh screen was predicted. It is indicated that the screen erosion rate is in an exponential relation with fluid velocity and in a linear relation with sand concentration. The higher the fluid velocity and sand concentration are, the greater the erosion rate is. In addition, the fluid velocity and erosion rate at different mesh layers are different. When the inlet fluid velocity is in the range of 0.5-2.0 m/s, the fluid velocity and erosion rate at the first mesh layer are 2.32-4.20 times and 10.91-15.96 times those at the inlet, and the fluid velocity and erosion rate at the second layer are 1.60-2.10 times and 3.00-5.58 times. What’s more, screen erosion damage firstly happens at the first mesh layer, and the increase of the fluid velocity at the first layer due to the structure of the screen is the main cause of mesh erosion damage. The minimum error between the screen erosion life predicted by the discrete flow numerical simulation method at different fluid velocities and the value monitored on site is 2.0%. In conclusion, this method provides a new technical means for predicting sand erosion life of metal mesh screen in gas wells.