Sintered metal substitute for prepack screen aggregate

A sand screen for placement within a well bore comprising, in combination:

• an elongated tubular mandrel having a plurality of longitudinally spaced apertures formed radially therethrough;
• an outer wire screen mounted onto said mandrel in substantially concentric alignment with said mandrel, said outer wire screen having circumferentially spaced, longitudinally extending outer rib wires and an outer screen wire wrapped externally about said outer rib wires and welded thereto at substantially all points of contact therewith, thereby defining longitudinally spaced outer screen apertures for conducting formation fluids through said outer screen;
• an annular weld formed on said mandrel and connecting the end portions of said outer screen wires and said outer rib wires together for centering said screen in radially spaced relation with said mandrel, thereby defining a prepack annulus;
• and,
• a permeable, sintered metal sleeve disposed within said prepack annulus.

An improved well screen of the type having a fluid-porous, particulate-restricting member for separating unconsolidated material out of formation fluid, characterized in that the particulate-restricting member is a porous, tubular body of sintered powdered metal formed by the following steps:

• depositing metal slivers having an average length of from about 50 microns to about 1,400 microns into a mold;
• compressing the metal slivers within the mold;
• and,
• baking the compressed slivers in an oven at a temperature sufficient to cause the slivers to become tacky and bonded to each other, thereby forming a metallurgically integral, porous structure having pore openings in the flow area size range of from about 20 microns to about 150 microns.

A well screen for separating particulated material from formation fluid comprising, in combination:

• a perforated, tubular mandrel;
• a permeable sleeve of sintered metal concentrically mounted on said tubular mandrel;
• and,
• a fluid-porous, particulate-restricting member mounted on said sintered metal sleeve.

A sand screen for placement within a well bore comprising, in combination:

• an elongated mandrel having a tubular sidewall and a plurality of longitudinally spaced apertures formed radially therethrough;
• a permeable, sintered metal sleeve concentrically mounted on said mandrel;
• and,
• a wire screen mounted on said mandrel in substantially concentric alignment with said sintered metal sleeve, said wire screen having a wire wrapped externally about said sintered metal sleeve, thereby defining longitudinally spaced outer screen apertures for conducting formation fluids.

A method for making a prepack sleeve for a well screen comprising the steps:

• (a) producing metal slivers in average lengths in the range of from about 50 microns to about 1,400 microns;
• (b) compressing the slivers to approximately 60,000 to 65,000 pounds per square inch within a mold;
• and,
• (c) sintering the compressed slivers in an oven at a temperature in the range of from about 1,600 to about 2,100 degrees Fahrenheit until the slivers become tacky and bond to each other.