Well shroud and sand control screen apparatus and completion method

摘要

Improved methods and apparatus for completing a subterranean zone penetrated by a wellbore are provided. The improved methods basically comprise the steps of placing a sand control screen (e.g., screens, screened pipes, perforated liners, prepacked screens, etc.) and an outer shroud assembly mounted over the sand screen in the wellbore adjacent the zone to be completed, the shroud having perforated and blank (non-perforated) segments with the blank segments corresponding to selected intervals of the wellbore, for example problem zones such as shale streaks or isolated zones where flows are restricted by mechanical seals or packers, and injecting particulate material into the wellbore, whereby gravel packing takes place in the remaining length of the wellbore/shroud annulus without voids. The inner annulus between the shroud and screen provides an alternate flow path for the slurry to bypass the blocked intervals and continue with its placement. Mechanical seals or packers may be used in combination with the shroud and associated sand screen. The method is also applicable to placing gravel packs in a cased and perforated well drilled in the zone.