Well liner with dual concentric half screens

Abstract

A well liner having dual concentric half screens for filtering sand and undesirables from fluids, gases, and toxic extractions. The well liner provides concentric half bodied screens of opposite orientation to provide a tortuous flow of path for the production fluids. The screens are manufactured by techniques well known in the art in the preferred embodiment. Two screen members are provided each comprising two annular portions: a screen portion and a solid pipe portion. The inner screen member is inserted in the outer screen member and both members are welded at each end. Additionally, an apertured base pipe may be provided. In the alternate embodiment, an apertured base pipe is surrounded by two full screen tubular members. A tortuous flow path is created in the alternative embodiment by the placement of shield members along a portion of the inner and outer screens. Additionally, the shields may be varied depending upon the placement of the apertures along the base pipe. These well liners are particularly suited for horizontal or high angle wells requiring a tortuous flow path where formation sand is likely to clog the well liners. The well bores may further be gravel packed to prevent or limit formation sand movement.