Certain aspects of the present invention are directed to a porous medium screen that can be disposed in a wellbore through a fluid-producing formation. The porous medium screen can include a porous medium and a retaining structure. The porous medium can be a material having one or more pores. The pores can be adapted to allow a fluid to flow through the porous medium and to prevent particles from flowing through the porous medium. The retaining structure can be adapted to retain the porous medium in a position circumferentially surrounding a section of a tubing string and to prevent expansion of the porous medium. The retaining structure can include a shroud and one or more stoppers. The shroud can be adapted to circumferentially surround the porous medium. Each stopper can be adapted to circumferentially surround the section of a tubing string at an edge of the porous medium.