Abstract: A sand filter for use in a well is provided employing a length of perforated tubing. A tubular wedge wire screen is telescopically positioned on the tubing covering the perforations. A plurality of tubular corrugated filter elements are then positioned on the wedge wire screen in end-to-end relationship. Each of the filter elements is formed of diffusion bonded multiple layers of wire mesh and each of the filter elements is corrugated to provide an external surface having an area at least three times the area of the cylindrical external surface of the tubular wedge wire screen that is encompassed by each filter element. The corrugated filter elements are secured on the wedge wire screen and welded in abutted end-to-end position.

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 well screen for a horizontal or high-angle well includes a screen main body and a protective frame. The screen main body has screen rods arranged in the circumferential direction of the well screen and a screen wire wound on the screen rods. The protective frame includes protective rods provided on the outside of the screen wire in the circumferential direction and extending in the axial direction of the well screen, annular rod holding members provided with interval in the axial direction for holding the protective rods, and a protective wire wound about the protective rods. When the well screen forced into the well passes through a bent section of the well, the protective frame slides in contact with the wall surface of the bent section thereby protecting the screen wire.

Abstract: A method of manufacturing a selective isolation screen includes steps of fitting a plurality of screen jackets one by one on a base member, each of the screen jackets including a plurality of spacer members extending in the longitudinal direction to be disposed, circumferentially spaced, on the base member and a wire wound about the periphery of the spacer members with a predetermined gap, and welding the end portions of each screen jacket to the base member thereby fixing the screen jacket to the base member and also forming seal means and thus constituting a single unit screen. Difficulty in welding can thereby be avoided and location and state of mounting of sleeves can be visually checked.

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 sand screen assembly has resistance welded inner and outer screens concentrically mounted in radially spaced relation onto a perforated mandrel, thereby defining an annulus in which prepack gravel is loaded. The longitudinal spacing distance between adjacent turns of the inner and outer screens selectively exclude sand fines of a predetermined minimum size. The outer screen wire is substantially greater in size as compared to the corresponding dimension of the inner retention screen wire. The inner retention screen is radially spaced with respect to the perforated mandrel, thereby defining a bypass flow annulus. The effective inlet flow area through the inner retention screen is more than twice the effective inlet flow area through the outer screen. Accordingly, localized deposits of sand fines on the inner screen are effectively bypassed by the remaining flow passages formed across the inner retention screen.

Abstract: An arrangement for driving out volatile impurities from a ground water with a well shaft extending to the region of the ground water to be purified, the arrangement comprises an element for producing a negative pressure in the well shaft and supplying a gas underneath a water level in the well shaft, an element for providing a plurality of capillary openings in an upper sieve wall portion of the well shaft at least in a purification region between a gas inlet and a water level in the well shaft to enhance a laminary flow of ground water with relatively high speed, the capillary openings forming a greater free throughflow surface than a remaining portion of the well shaft.

Abstract: 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.

Abstract: This invention relates to a wire locking structure for a filter device, in which an outer circumference of a cylinder body is provided with a screw thread portion. The screw thread portion is wrapped by a wire of isosceles triangle in section. An end of the wire is drawn into a recess and firmly supported in a U-shape by an insert member to be inserted in the recess, thereby a conventional welding means has been removed.

Abstract: This invention relates to a wire locking structure for a filter device, in which an outer circumference of a cylinder body is provided with a screw thread portion. The screw thread portion is wrapped by a wire of isosceles triangle in section. An end of the wire is drawn into a recess and firmly supported in a U-shape by an insert member to be inserted in the recess, thereby a conventional welding means has been removed.

Abstract: A screen device is provided for use in a subterranean well and is carriable within the well on a tubular conduit. The screen has an elongated outer housing with a plurality of flow passageways extending through the housing. An inner perforable cylindrical mandrel with upper and lower ends has at least one of the ends securable with a conduit member of the tubular conduit. The mandrel longitudinally extends through the interior of the housing and is secured against movement relative to the housing. A central passageway in the mandrel communicates with the tubular conduit for transmission of fluid. Prior to perforation of the mandrel, the screen device prevents fluid flow between the flow passageways and the central passageway of the mandrel. Subsequent to perforation of the mandrel, the screen device permits transmission of fluid between the flow passageways, the central passageway and the tubular conduit.

Abstract: A downhole tool suction screen assembly includes a top screen assembly adapter, a lower screen assembly adapter, and a tubular screen mandrel connected between the top and lower screen assembly adapters. A cylindrical pump screen is disposed about an outer surface of the screen mandrel. A discharge passage is disposed in the screen assembly for communicating a discharge of a downhole pump with a lower end of the lower screen assembly adapter. A suction inlet passage is disposed in the screen assembly for communicating the outer surface of the screen mandrel with an intake of the downhole pump through the top screen assembly adapter.

Abstract: Mounting arrangement for a bimetallic pipe base well screen which must operate at elevated temperatures utilizes a weld for joining one end of a cylindrical screen member to the outer surface of an internal pipe member which has perforations along a portion of its length underlying the well screen. The opposite end of the screen member, which has a greater temperature coefficient of expansion than the pipe base, has an internal boss or ring portion which, at room temperature, has a smaller inner diameter than the outer diameter of the pipe base. The ring portion is heated and shrunk-fit onto the pipe base to a degree that at operational temperatures it will either expand slightly out of contact with the pipe base, or at least become substantially unstressed, thus preventing damage to the screen member while also blocking out the entry of particles.

Abstract: Natural gas and thermal energy are produced from aquifers containing appreciable quantities of dissolved natural gas at or near saturation levels in the aquifer water, with or without associated dispersed vapor phase gas, using a particular method and apparatus.

Abstract: A perforated pipe and method of making the same for use in wells, screen and the like, the perforations being in the form of sets of oppositely disposed slits in a tubular member defined along a helical path; the preparation being characterized as self-cleaning and resulting from a balanced forming operation to substantially reduce warpage.

Abstract: A new torque drive mechanism is disclosed between a reversible rotatable square bar means for rotating a washer while providing free longitudinal movement of the square rod in the washer, and for providing free passage of liquid therebetween the bar and the washer.

Abstract: Method for assembling a self-cleaning helical spring sand screen for use at the petroliferous unconsolidated sand strata of an oil well are disclosed. The basic method comprises (1) attaching a helical spring sand screen to the lower end of a production tube for being lowered into a well to the liquid level for producing sand-free liquid from the production tube, (2) mounting a spring biased valve means on the production tube, (3) providing valve means for the production tube for controlling the outlet thereof, and (4) connecting a source of high pressure liquid to the spring biased valve means for storing energy in its spring, for expanding its helical spring sand screen, and for ejecting liquid into its helical spring sand screen for expansion and cleaning thereof.

Abstract: Assembly of a coated screen jacket and a coated pipe base is held together by radially positioned fasteners such as shear pins which pass through overlapping portions of male and female slip fittings which are welded to the screen jacket and pipe base before it is coated. The mating fittings include an internal groove for mounting an O-ring. Since the screen jacket has complementary male and female fittings on its opposite ends, a plurality of short screen jacket portions can be easily mounted in series on a pipe base member.

Abstract: A method for cleaning a helical spring screen that has become clogged up while filtering liquid deep in a well and while simultaneously producing filtered liquid from the well comprises (1) positioning a cleaning washer with a large opening therein between two coils at one end of the helical spring screen, and (2) rotating the cleaning washer with a rotatable rod of a smaller circumference between all of the coils to the other end of the spring screen for cleaning all foreign material from between the coils of the spring screen, and for simultaneously producing filtered liquid through the cleaning washer large opening while sliding over the rod from one end to the other. A method for forming or assembling a self-cleaning helical screen and two modifications of a new and improved self-cleaning helical spring screen are also disclosed herein.

Abstract: Methods for cleaning sand from a helical spring sand filter, methods for assembling a self-cleaning helical spring sand filter, and a self-cleaning helical spring sand filter for use at the petroliferous unconsolidated sand strata of an oil well are disclosed. The filter comprises a helical spring connected in tension at each end to an elongated perforated sleeve for spacing apart all convolutions by a predetermined distance for forming the filter. One or more washer shaped cleaning rings with square holes therein are mounted between adjacent convolutions at one end of the spring for being rotated by a square ended rod supported by a sucker rod in a well between all of the convolutions to the spring other end for scraping off all foreign material from between the convolutions. The spring sand filter can be cleaned for as many times as there are cleaning rings instead of making trips to the surface for unclogging.

Abstract: Mounting arrangement for a pipe base well screen utilizes a weld for joining one end of a cylindrical screen member to the outer surface of an internal pipe member which has perforations along a portion of its length underlying the well screen. The opposite free end of the screen member includes an elongated sleeve portion which supports an internal elastomeric O-ring member in a groove. The O-ring seals the screen member to an unperforated portion of the pipe base and permits the pipe to be subjected to substantial tensile and torsional stresses without destroying the screen as often happens when a screen is welded at each of its ends.

Abstract: Improved plastic well screen is stronger and more economical to produce than prior art screens. An extruded inner core member has a generally corrugated or fluted configuration with the radial walls each including stepped right angled portions for increasing the rigidity of the core. An enwrapment wire is welded to the core to define the screen slots. Channels in the core permit flow even when a pumping means occludes the I.D. of the core.

Abstract: The perforations of a tubular pipe are sealed with a selectively removable plugging material. The pipe is then wire wrapped to form a well screen. The annular passage defined by the pipe and wire wrapping is restricted enough so that the flow resistance in the annular passage is sufficient to maintain high fluid flow velocity outside the well screen during gravel packing so as to prevent the formation of gravel dunes. After gravel packing is completed, the plugging material is removed, permitting the passage of fluids through the well screen and pipe mandrel.

Abstract: Deep well screen and method of making same wherein a wire screen sleeve having longitudinal wires arranged in a generally cylindrical shape, with external wrapping wire welded thereto, is positioned over a perforated pipe having an external diameter substantially equal to the internal diameter of the sleeve, and wherein annular welds are provided between each end of said wire screen and said pipe to close the space therebetween at such ends and to secure the sleeve to the pipe without exceeding the external diameter of said wrapping wires.

Abstract: One of at least two different spring filters comprises a helically grooved hollow mandrel with holes in the grooves and a helical spring closely fitted therearound. The pitch of the spring convolutions is opposite to that of the mandrel grooves so that the mandrel provides lateral support to the spring equivalent to that provided by a solid cylindrical bar for maintaining uniform diameter and concentricity of the spring convolutions while eliminating lateral displacement thereof during high load operations. While this filter is secured at its bottom to the well, a modification requires securing thereof only at its top to the well with a packer. Further, full width spacers are formed on the spring convolutions for precise separation thereof and for preventing twisting and lateral displacement of the individual convolutions and for prevention of any variation of the gauge between the adjacent helical spring convolutions particularly while under magnified loads.

Abstract: This is a special downhole multi-layer sand screen for oil and other fluids containing sand. The preferred embodiment of the sand filter includes an outer screen, an intermediate screen and an inner screen although another embodiment may have only an outer and an inner screen. The outermost screen is of larger spacing to retain only the coarser sand particles and the openings in the inner two screens are progressively smaller to retain the less coarse sand material. The coarser sand particles bridge about the larger openings in the outer screens and progressively finer sand materials bridge across the intermediate and inner screens.