A downhole filter comprises a tubular member having a wall defining a plurality of openings. The openings have an outer width less than an inner width. The parts of the opening defining the smaller width are defined by radially outer parts of the openings, such that particulates or sand prevented from passing through the openings will tend to be retained to the outside of the tubular member. A method comprises providing a tubular string having a non-porous tubular portion and a porous tubular portion, and installing the tubular string within a wellbore such that the porous tubular portion is located adjacent a fluid-producing formation within the wellbore. In another embodiment, an apparatus comprises a drill string comprising a non-porous tubular portion and a porous tubular portion, and an earth removal member operatively connected to a lower end of the drill string.