A well liner having a selective isolation screen comprises an elongate base pipe having a predetermined number of openings therethrough which is surrounded by circumferentially spaced, longitudinally extending spacer bars, one or more annular cylindrical sleeves secured to the exterior of the base pipe and a continuous wire wrapped therearound to form an inner annulus isolated at predetermined vertical locations corresponding to specific well requirements of varying lengths and production formations within the wellbore. The continuous wire is wrapped over the spacer bars and sleeves in a spaced spiral configuration to provide a predetermined constant gap between the wire wrapping. The gaps in the wire wrapping are sized to stop the movement of the formation sand and allow continual flow of fluid into the wellbore. Gravel or other particulate matter may be pumped down the borehole in the outer annulus between the interior of the borehole or an outer casing and the outer surface of the wire wrapping. The gravel and other particulates are sized to restrain movement of the formation sand and the screen openings or gaps are designed to restrain the movement of the gravel or particulates to allow continual flow of fluids therethrough.

A method and device for removing sand from hydrocarbonaceous fluids whereby a berm is formed adjacent to a slot which has penetrated a liner or perforated tube. The berm which is formed along each side of said slot operates to form a lip or platform so as to provide a solid base upon which to form a sand bridge to more effectively remove sand from hydrocarbonaceous fluids produced from the well.

A well liner for a subterranean well is provided comprising an elongated tubular member which may be a wire wrapped screen having a plurality of slots or passages which are disposed longitudinally and circumferentially of and extending from the outer surface to the inner surface of the tubular member, and an impermeable inorganic matrix substantially filling said slots or passages and coated upon said inner and outer surfaces, said matrix being the reaction product of a first reactant consisting essentialy of magnesium oxide and a second reactant consisting essentially of magnesium chloride, in a solvent or solution therefor.

Cement compositions which upon curing have high compressive strengths and are rapidly dissolved in acids are provided comprised of water, a metal halide or sulfate selected from the group consisting of magnesium, aluminum and zinc halides and sulfates, a metal oxide selected from the group consisting of magnesium, aluminum and zinc oxides and a metal carbonate selected from the group consisting of calcium and barium carbonates. Methods of using the cement compositions are also provided.

A perforated liner is sealed at longitudinally spaced intervals with a removable sealant. The partially sealed liner maintains sufficiently high fluid flow velocity outside the liner during gravel packing so as to prevent the formation of gravel dunes. After packing is completed, the sealant is removed permitting the passage of fluids through the liner.