The Influence of Structural Parameters on the Plugging of Prepacked Gravel Screens

Offshore oil reservoirs are mostly loose sandstone. Sand control completion is usually required. However, sand control screens are easily blocked during production, reducing the productivity of oil wells considerably. The optimization of the sand control screen is still a challenge to date because of the lack of insights into the screen plugging process. In this study, a CFD-DEM method was introduced to analyze the effect of structural parameters on the plugging of a newly designed prepacked gravel screen (PPGS). Numerical results show that the pore size formed by gravel and punched slot is much smaller than the pore size formed by gravel under high packing efficiency. Thus, it is easy to cause a large amount of silty clay to stay on the surface of the screen, intensifying the blockage of the screen. On the contrary, the collapsing of bridges in gravels can be observed under low packing efficiency, enhancing the no-plugging capacity of the new PPGS to some extent. Moreover, numerical results also show that optimizing gravel size is closely related to the packing efficiency and punched slot size. A comparison with full-size experiments shows that, although the numerical simulations have some deviations in specific values from the experiments, the trend of the impact of each factor on the plugging of the screen is consistent between the numerical and experimental studies. This consistency illustrates that the CFD–DEM method provided in this study can be used to investigate the plugging mechanism of the sand control screen in the future.