Multi-layer screen and downhole completion method

摘要

The invention relates to an expandable filter assembly for downhole use and comprises a base pipe (10) having an inside surface, a plurality of openings (12) and at least one filtration layer (26) mounted over the pipe. The filtration layer (26) comprises a weave (see Fig. 2) having weft (28) and warp (30) wires wherein one of said wires is disposed at an angle of about 10-80 degrees with respect to the longitudinal axis of the base pipe (10). The diameter of the weft wires (28) may be up to 50% larger than the diameter of the warp wires (30).