Well screen with prepacked screen element

摘要

A prepack well screen assembly has a resistance welded outer screen (42) concentrically mounted in radially spaced relation on a perforated mandrel (38), thereby defining an annulus in which a sintered metal prepack sleeve (44) is loaded. The longitudinal spacing distance between adjacent turns of the outer screen (42) selectively exclude sand fines of a predetermined minimum size. The porosity of the sintered metal prepack sleeve (44) is selected to pass sand fines in the size range of from about 10 microns ( mu m) to about 150 microns ( mu m). The effective inlet flow area through the sintered metal prepack sleeve (44) is substantially greater than the effective inlet flow area through the outer screen (42). The sintered metal prepack sleeve excludes sand fines from inflowing formation fluid during the initial production phase following a gravel pack operation, without limiting production of formation fluid.