Abstract: A sand screen having a plurality of sintered, substantially spherical plastic members covering a perforated mandrel is releasably suspended from a packer mandrel by a locking mandrel and a landing nipple. The sand screen and locking mandrel are retrievable with the assistance of a running tool which is insertable into the bore of the locking mandrel. According to this arrangement, the sand screen can be removed and replaced without retrieving the packer or the production tubing. In one embodiment, the sand screen is enclosed within the bore of a sliding side valve. The sliding side valve can be opened and closed as desired for selectively admitting production from various producing zones, or for isolation of a damaged screen. In another embodiment, an auxiliary sand screen having a plurality of sintered, substantially spherical plastic members covering a perforated mandrel is inserted into the bore of a primary screen, for example, a conventional wire-wrap sand screen.

Abstract: A prepack well screen assembly for separating particulate material from formation fluid has inner and outer screens concentrically mounted in radially spaced relation around a perforated mandrel, thereby defining a prepack annulus in which a plurality of spherical plastic members are disposed. The concentric inner screen includes longitudinally extending rib wires spaced circumferentially around the mandrel, and a screen wire wrapped externally about the rib wires in a longitudinally spaced pattern to define spaced screen apertures for conducting formation fluids through the inner screen. The outer screen is a cylindrical fluid-porous, particulate-restricting member which is radially spaced from the inner screen to form the prepack annulus. The particulate-restricting member includes rib wires which are spaced circumferentially around the inner screen within the prepack annulus, and an outer screen wire wrapped externally about the rib wires to define the annulus.

Abstract: Multiple sintered metal sand screen sections are mechanically coupled to a perforated screen mandrel in an arrangement which is capable of sustaining normal bending loads associated with run-in in highly deviated and horizontal well bores, without breaking the mechanical connections or otherwise damaging or impairing the structural integrity of the sintered metal screen sections. The multiple screen sections are held under compression by end collars. Adjacent screen sections are separated by annular spacing rings and by resilient seal rings which seal the union between adjacent end portions of the sintered metal screen sections. The end collars are welded directly onto the screen mandrel, with the sintered metal screen sections being stabilized about the perforated mandrel by longitudinal compression loading, so that it is not necessary to form a weld joint on the sintered metal material.

Abstract: A prepack well screen assembly has a resistance welded outer screen concentrically mounted in radially spaced relation on a perforated mandrel, thereby defining an annulus in which a sintered metal prepack sleeve is loaded. The longitudinal spacing distance between adjacent turns of the outer screen selectively exclude sand fines of a predetermined minimum size. The porosity of the sintered metal prepack sleeve is selected to pass sand fines in the size range of from about 10 microns to about 150 microns. The effective inlet flow area through the sintered metal prepack sleeve is substantially greater than the effective inlet flow area through the outer screen. The sintered metal prepack screen excludes sand fines from inflowing formation fluid during the initial production phase following a gravel pack operation, without limiting production of formation fluid.

Abstract: A prepack well screen assembly has a resistance welded outer screen concentrically mounted in radially spaced relation on a perforated mandrel, thereby defining an annulus in which a sintered metal prepack sleeve is loaded. The longitudinal spacing distance between adjacent turns of the outer screen selectively exclude sand fines of a predetermined minimum size. The porosity of the sintered metal prepack sleeve is selected to pass sand fines in the size range of from about 20 microns to about 150 microns. The effective inlet flow area through the sintered metal prepack sleeve is substantially greater than the effective inlet flow area through the outer screen. The sintered metal prepack screen excludes sand fines from inflowing formation fluid during the initial production phase following a gravel pack operation, without limiting production of formation fluid.

Abstract: A tubular sand screen is made in one piece entirely of powdered metal slivers which are molded and sintered to form a metallurgically integral rigid tubular structure. Aggregate metal particles, for example, stainless steel slivers, are bonded together by interatomic diffusion as a result of sintering the compacted slivers under high temperature and pressure conditions. The sintered metal sand screen performs the function of the conventional prepack assembly as well as the screen function. In one aspect of the invention, the sintered metal screen is subjected to electropolishing to yield an effective porosity of 40-60 mesh, with an average pore size of 150 microns. Most of the surface irregularities are removed by electropolishing, and very few nucleation sites remain where particles in the size range of 74 microns-100 microns can become captured or otherwise lodged to cause plugging of the screen.

Abstract: A well screen centralizer with a longitudinal flow passage therethrough which has a well screen insert that increases the producing area of the well screen by reducing the amount of blank non-producing tubing length usually used to accommodate non-well screen insert centralizers. A method for constructing a well screen centralizer and a method for inserting well screens into a well bore that includes welding the couplings to the well screens and using a well screen assembly and support stand.

Abstract: A well screen centralizer with a longitudinal flow passage therethrough which has a well screen insert that increases the producing area of the well screen by reducing the amount of blank non-producing tubing length usually used to accommodate non-well screen insert centralizers. A method for constructing a well screen centralizer and a method for inserting well screens into a well bore that includes welding the couplings to the well screens and using a well screen assembly and support stand.