Abstract: Improved well screen has its open area defined by a helically wrapped strip of wire mesh which is supported by a rigid cage-like structure of welded steel longitudinal support rods and helical wrap wires. The design is cost competitive with the simple, and rather fragile, screens made by wrapping a mesh about a perforated pipe while offering the mechanical strength characteristics of wire-wrapped welded screens and a substantially larger open area for flow. The wire mesh strip is helically wound with a gap and at least one wrap wire is helically wound in the gap so that a small portion of its width can be firmly adhered to the rods while at least another portion of its width overlies an adjacent side edge of the mesh strip.

Abstract: End fitting assembly for a spiral wire wound well screen includes a fitting portion which is internally threaded at one end to threadedly engage with a plurality of external wire wraps of the well screen which are wound around a plurality of longitudinal support rods at a greater pitch than the main body of the screen. Preferably, the longitudinal support rods are welded at their tips to the interior surface of the fitting. The assembly technique greatly increases the tensile strength of the joint between the screen and fitting and can be equal to a combination of the individual strengths of a conventional welded fitting and a threaded fitting. Where utmost joint strength is not necessary and welding would not be desirable for reasons such as corrosion prevention, the wire wrap threads can provide all of the joint strength.

Abstract: The instant invention relates to an improved filtering device adapted to eliminate any risk of clogging of the filtering material. The invention provides a filtering device for treating any effluents, which comprises a plurality of filtering walls arranged successively between a chamber containing the effluent to be filtered and a chamber containing the filtered effluent, each filtering wall being constituted by spacedly justaposed strips having a trapezoidal section with the large base of the trapezoid located on the inlet face of the filtering wall, said strips being separated from each other, on the inlet face of the filtering wall, by intervals of equal widths forming slots which define effluent inlet areas, the sum of said inlet areas constituting the total inlet area of a filtering wall, and the total inlet area of the upstream wall being less than the total inlet area of the adjacent downstream wall.

Abstract: Filament reinforced cylindrical plastic screens having open slots defined by their surface wires which are of substantially different widths can be produced on a single helically finned mandrel. The slot widths are varied in accordance with the amount of wire-forming material placed in the generally V-shaped grooves defined by the mandrel fins. The grooves have a double relief angle so that the lower support portions of the surface wires will be formed so as to have a slightly tapered, radially elongated cross-section and the upper portions of the wires will have their sides at a substantially greater relief angle. This relationship permits a relatively small change in the total height of the wires to have a substantial effect on the width of the top portion of the wires, and thus, on the width of the slot openings which can be formed between adjacent wires.

Abstract: A fiber reinforced plastic well screen including a slotted central section and unslotted end fitting portions is formed by manipulating a single bundle of resin-coated filaments longitudinally and circumferentially relative to a mandrel. The mandrel has a series of helically grooved segments which cooperate with each other to cause the filament bundle to form the slotted central section. Longitudinal wraps, which are looped under tension from one end of the mandrel to the other in the region between each adjacent pair of segments, are intimately bonded to all of the helical circumferential wraps which form the central section as well as those that form the end fitting portions. One removable end cap portion of the mandrel is preferably externally threaded to produce an integral internal thread in the formed well screen. A tubular internal sleeve portion of the mandrel is removable to permit the helically grooved segments to be collapsed inwardly after the well screen is cured.

Abstract: A downhole testing apparatus has a modular construction including a pump assembly, a screen assembly, a first packer assembly, an intake port assembly, and a second packer assembly. Improvements are provided in each of the pump assembly, screen assembly, first packer assembly, and intake port assembly.

Abstract: Improved method of joining a rigid thermoplastic fitting to a rigid thermoplastic well screen having longitudinal support rods utilizes pressure and friction generated heat to bond a reduced diameter tubular, rigid thermoplastic sleeve portion of the fitting to the inner surface of the screen. The method permits the joining, without the use of solvents, of screens and fittings of PVC, polypropylene, or ABS, for example, which have the same outer diameters. The sleeve portion of the fitting has an outer diameter which is greater than the inner diameter of the well screen. The assembly method requires that the parts to be mated be rotated rapidly relative to each other as they are forced axially into interfering, telescopic engagement. The overlapping members are fused along a generally conically tapered plane with the material which is melted during rotation being deposited in the circumferential spaces between the screen's support rods.

Abstract: Plastic well screen has tapered, undercut slots formed by a laser beam focused through a lens having its focal point located at or slightly away from the surface of the plastic cylinder being slotted so that the laser beam diverges as it passes through the plastic. The cylinder is rotated and simultaneously moved axially relative to the laser beam to produce a series of transverse slots. In one embodiment, the laser beam is interrupted to provide continuous longitudinal support portions in the cylinder. In a modified embodiment, the cylinder has integral internal ribs which remain intact even though the laser is operated continuously to remove surface material located between the ribs and the laser beam.

Abstract: Plastic well screen has tapered, undercut slots formed by a laser beam focused through a lens having its focal point located at or slightly away from the surface of the plastic cylinder being slotted so that the laser beam diverges as it passes through the plastic. The cylinder is rotated and simultaneously moved axially relative to the laser beam to produce a series of transverse slots. In one embodiment, the laser beam is interrupted to provide continuous longitudinal support portions in the cylinder. In a modified embodiment, the cylinder has integral internal ribs which remain intact even though the laser is operated continuously to remove surface material located between the ribs and the laser beam.

Abstract: A well screen formed of an extruded wedge shaped plastic strip wound about cylindrically disposed supporting rods in which the flexible strip is extruded of dual durometer dissimilar materials in the form of a unitary strip having complementary characteristics in which one body portion is formed of a suitable substantially rigid plastic material and another body portion is formed of a plastic material which has relatively greater strength characteristics whereby in the event of cracking of one of the portions, the strip is held together in a useable condition by the other body portion and a coating of abrasive resistant material is extruded unitarily with the strip to form an outer surface portion having substantial resistance to wear.

Abstract: A method for cleaning sand from a 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: A method for cleaning a helical spring screen deep in a well while filtering liquid comprises (1) injecting a high pressure hydraulic surge pulse into the spring screen for expanding the coils, (2) forcing high pressure liquid between the coils of the helical spring screen simultaneously with expanding of the coils for washing the sand from between the coils, and (3) forcing the coils together following their expansion by expanding action of a second spring for crushing and dislodging any sand therebetween the coils for removal upon subsequent spreading of the coils. A second method is disclosed likewise. Thus the methods provide for the spring coils being cleaned for a multiplicity of times without having to shut the well in for workover, thus saving workover costs and lost production.

Abstract: A self-cleaning helical spring sand screen for use at the petroliferous unconsolidated sand strata of an oil well are disclosed. The sand screen comprises a hydraulically actuated, spring based spool valve connected to the upper end of the sand screen for receiving liquid under high pressure, for storing energy in the spring, for expanding the helical spring sand screen, and for ejecting liquid into the helical spring sand screen for cleaning thereof. Then upon ceasing of flow of the high pressure liquid, the stored energy in another spring contracts the helical spring sand screen for restorating production of sand-free oil from the production tube. A second modification is disclosed.

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: 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: A method for cleaning a helical spring screen deep in a well while filtering liquid comprises (1) injecting a high pressure hydraulic surge pulse into the spring screen for expanding the coils, (2) forcing high pressure liquid between the coils of the helical spring screen simultaneously with expanding of the coils for washing the sand from between the coils, and (3) forcing the coils together following their expansion by expanding action of a second spring for crushing and dislodging any sand therebetween the coils for removal upon subsequent spreading of the coils. A second method is disclosed likewise. Methods for forming a self-cleaning helical spring screen and two modifications of a helical spring screen are disclosed herein for being cleaned for a multiplicity of times without having to shut the well in for workover, thus saving workover costs and lost production.

Abstract: The well screen assembly disclosed includes a perforated pipe joint having a well screen mounted internally of the pipe joint. The well screen includes a plurality of rods positioned parallel to and spaced from the longitudinal axis of the pipe joint with an elongated wire helically wrapped around the outside of the rods and positioned between the rods and the inside wall of the pipe joint. The wire is wrapped so that the spaces between the wire screen solid particles out of the well fluid as the fluid flows between the slots in the wire into the inside of the well screen. The well screen is spaced from the inside surface of the pipe joint to allow fluid to flow freely around the outside of the well screen after the fluid passes through the perforations in the pipe joint. Means are provided to mount the screen in the pipe joint and to retain gravel, in the space between the well screen and the inside surface of the pipe joint, if the screen is gravel packed.

Abstract: Apparatus for separating particulate matter from a flowing fluid which, for example, may be sand entrained in a flowing stream of oil and gas, comprises an assembly including a plurality of small diameter tubular elements, the walls of which have a selected permeability to said fluid. The tubular elements are held with their axes parallel between a pair of headers by suitable tension means. The interior of the tubes are connected to at least one plenum and to a well tubing. When this assembly is inserted into a well producing oil and gas which carries sand, the sand will be deposited against the outer walls of the tubular elements since the grain diameters are greater than the size of the openings in the walls of the tubular elements. The fluid flows through the openings in the wall of the tubular element, into the plenum and then through the well tubing to the surface of the well. By using suitable headers at each end, a plurality of these assemblies can be connected in series.