Abstract: The invention involves the use of a base pipe perforated only in a specific section under each screen section. Inflow comes through an outer shroud that is optional and goes through the screen material and into an annular space between the screen material and the unperforated base pipe. After traveling longitudinally in that annular space, the flow must go through a restriction that preferably comprises a porous media in a passage defined outside the still unperforated base pipe. After passing through the porous media in a particular screen section, the flow can pass through openings in the base pipe. A surrounding ring preferably protects the porous media during run in and expansion and can also optionally create additional resistance to flow to work in tandem with the porous media. Other flow restricting techniques in place of the porous media are contemplated.

Abstract: An assembly method for a downhole screen is disclosed. In the preferred embodiment, the filtration layer is slipped over a perforated base pipe and an expansion technique is used to increase the base pipe diameter to the point where, preferably, an interference fit exists. The expansion can be fully underneath the filtration layer or can be done in discrete zones. The finished assembly can still be expanded further downhole, such as, for example, in open hole completions. An outer protective shroud can be employed over the filtration layer when the expansion of the base pipe occurs.