Multi-layered metal-mesh screens (MMSs) are widely used as stand-alone screens for sand control in unconsolidated formations. The nominal rating of such screens is usually based on the specifications of the filter layer. It is often found that screens with the same filter layer nominal rating perform differently. It is shown in this study that primary reason for this is that the sand retention performance of MMSs is a strong function of not only the filter layer but also the support and the protection layers.

This paper presents a systematic study that shows how the overlap between different screen layers, the alignment of the support and protection layers, and the relative pore size ratio, defined as the ratio of pore size of the protection/support layer to that of the filter layer, have a large impact on the sand retention performance of a MMS. In this paper, the pore size distribution (PoSD) and the average pore size of a multilayered plain-square mesh (PSM) are calculated using a novel numerical technique. This data is used as an input into validated analytical models for predicting sand production of PSM screens in slurry tests. These steps are repeated for PSM screens with different geometries and their sand retention performances are compared.

The results show that the PoSD of a multilayered PSM screen can be very different from the PoSD of the filter layer. In addition, the number-averaged pore size of the PSM cannot always be used to estimate the sand production; instead, the entire PoSD should be used. In general, a decrease in sand production with an increase in layer overlap is observed; the trend exists irrespective of how mesh layers are aligned. A change in mesh alignment is found to cause a variation in sand production even with the same filter layer pore size and overlap between layers. When the pore size of the support/protection layers is much larger than the filter layer pore size, the number averaged pore size of the multilayered PSM (different from the nominal rating) can be used to estimate sand production.

This paper clearly shows that layer overlap, layer alignment, and relative pore size ratio between mesh layers, all affect the sand retention performance of a multi-layered MMS. These factors are seldom considered when selecting a screen. As such widely different screen performances can be expected for screens with the same nominal screen rating. Our results have a direct bearing on how MMSs are manufactured and they are selected and specified. Increasing the relative pore size ratio appears to be a promising screen-design approach to obtain consistent screen performance for multi-layered MMSs.