WO2003091536A1 - Cylindrical well screen having longitudinal skid rods - Google Patents

Cylindrical well screen having longitudinal skid rods Download PDF

Info

Publication number
WO2003091536A1
WO2003091536A1 PCT/JP2003/004801 JP0304801W WO03091536A1 WO 2003091536 A1 WO2003091536 A1 WO 2003091536A1 JP 0304801 W JP0304801 W JP 0304801W WO 03091536 A1 WO03091536 A1 WO 03091536A1
Authority
WO
WIPO (PCT)
Prior art keywords
screen
rods
protective
wire
well
Prior art date
Application number
PCT/JP2003/004801
Other languages
French (fr)
Inventor
Tadayoshi Nagaoka
Original Assignee
Tadayoshi Nagaoka
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tadayoshi Nagaoka filed Critical Tadayoshi Nagaoka
Priority to AU2003230239A priority Critical patent/AU2003230239A1/en
Publication of WO2003091536A1 publication Critical patent/WO2003091536A1/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/02—Subsoil filtering
    • E21B43/08—Screens or liners
    • E21B43/088—Wire screens
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/111—Making filtering elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/13—Supported filter elements
    • B01D29/15—Supported filter elements arranged for inward flow filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/44—Edge filtering elements, i.e. using contiguous impervious surfaces
    • B01D29/48—Edge filtering elements, i.e. using contiguous impervious surfaces of spirally or helically wound bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
    • B01D29/56—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in series connection
    • B01D29/58—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in series connection arranged concentrically or coaxially
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/02—Subsoil filtering
    • E21B43/08—Screens or liners
    • E21B43/084—Screens comprising woven materials, e.g. mesh or cloth
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/02—Subsoil filtering
    • E21B43/08—Screens or liners
    • E21B43/086—Screens with preformed openings, e.g. slotted liners

Definitions

  • This invention relates to a well screen for a horizontal or high-angle well screen and, more particularly, to this type of well screen for a horizontal or high-angle oil well capable of facilitating insertion of this type of screen into the horizontal or high-angle well.
  • FIG.7A and a sectional view of FIG. 7B taken along arrows A - A of Fig. 7A show one of such horizontal or high- angle well which is formed by digging the ground from a vertical portion 100a through a curved portion 100b to a horizontal or inclined portion 100c which extends in the horizontal or inclined direction along the oil stratum. Since this type of horizontal or high- angle well has a screen section for collecting oil which is several times as long as a conventional vertical well, the horizontal or high- angle well has the advantage that it has a superior production efficiency which is several times as high as that of the vertical well.
  • the well screen is required to have a slit having a size which is sufficient for preventing invasion of sand grains and, for this purpose, a spiral wire type screen is generally used as the well screen.
  • an object of the invention to provide a cylindrical well screen capable of facilitating insertion of the well screen and thereby shortening the working time for inserting the well screen and preventing blocking or damage of the slit of the screen.
  • a cylindrical well screen comprising a plurality of skid rods made of metal extending in the axial direction of the screen, being arranged at a predetermined interval in the circumferential direction of the screen and welded to the outer surface of the screen.
  • the skid rods perform the function of a sledge for the screen during insertion of the well screen into the well and thereby decreasing friction between the outer surface of the well screen and the wall of the well-bore and, as a result, the screen can be inserted smoothly into the well and time required for inserting the well screen into the well can be shortened.
  • the skid rods protect the outermost spiral wire from the outside so that the spiral wire and its slit do not come into direct contact with the wall of the well-bore, damage of the slit due to contact with the wall of the well-bore can be prevented.
  • the width of the slit in the top portion of the spiral wire tends to become small and the width of the slit in the bottom portion of the spiral wire tends to become large by bending of the screen with resulting deformation of the slit.
  • the skid rods are welded to the outer surface of the spiral wire in the axial direction of the well screen and, therefore, deformation of the slit can be prevented.
  • the slit of the spiral wire does not come into direct contact with the wall of the well-bore during insertion of the well screen into the well, blocking of the slit due to fine sand grains of the wall of the well -bore during insertion of the well screen can be effectively prevented.
  • the well screen further comprises support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, and a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, said skid rods being welded to the outer surface of the spiral wire.
  • the well screen further comprises a screen wire and a protective frame
  • said protective frame comprising a plurality of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, a plurality of annular rod holding members provided at a predetermined interval in the axial direction of the screen for holding the protective rods, protective wire means provided about the protective rods in the circumferential direction of the screen, and a circumferential gap of a predetermined value, said gap being formed between the protective rods and the outer surface of the screen wire and extending longitudinally between the plurality of annular rod holding members, said skid rod being welded to the outer surface of the protective wire of the protective frame.
  • the well screen comprises a screen wire and a protective frame
  • said protective frame comprising a plurality of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen and protective wire means provided about the protective rods in the circumferential direction of the screen, said protective rods being in pressed contact with the screen wire by tight winding of the protective wire on the protective rods and the skid rods being welded to the outer surface of the protective wire of the protective frame.
  • the well screen further comprises a perforated base pipe perforated with a multiplicity of fluid taking openings, a plurality of support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen with a predetermined interval in the radial direction of the screen on the outside of the perforated base pipe so as to define an annulus between the perforated base pipe and the support rods, a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, and a filter member provided in the annulus between the perforated base pipe and the support rods, said skid rods being welded to the outer surface of the spiral wire.
  • FIG. 1 is a perspective view showing a preferred embodiment of the invention
  • FIG. 2 is a perspective view showing a part of the embodiment in an enlarged scale!
  • FIG. 3 is a perspective view showing another embodiment of the invention.
  • FIG. 4 is a perspective view showing another embodiment of the invention.
  • FIG. 5 is a perspective view showing another embodiment of the invention.
  • FIG. 6 is a perspective view showing another embodiment of the invention.
  • FIGs. 7A and 7B are sectional views showing a horizontal well screen.
  • FIG. 1 shows an embodiment of the cylindrical well screen having longitudinal skid rods made according to the present invention and FIG. 2 shows a part of the embodiment in an enlarged scale.
  • a cylindrical well screen 1 comprises support rods 2 extending in the axial direction of the screen 1 and arranged at a predetermined interval in the circumferential direction of the screen 1, a spiral wedge-wire 3 wound on the outer surface of the support rods so as to form a slit 3a of a predetermined width, a plurality of skid rods 4 made of metal rods extending in the axial direction of the screen 1, being arranged at a predetermined interval in the circumferential direction of the screen 1 and welded to a flat outer surface 3b of the spiral wedge- wire 3.
  • the support rods 2 support the spiral wedge-wire 3 and are made of steel rods having a circular cross section.
  • the support rods 2 may be of other shape in cross section such as a polygonal shape.
  • the support rods 2 are arranged generally cylindrically at a predetermined interval.
  • the spiral wedge-wire 3 On the outer surface of the support rods 2 is wound the spiral wedge-wire 3 in the direction substantially crossing the support rods 2.
  • the spiral wecge-wire 3 is arranged in such a manner that its flat surface 3b faces outside and the other two sides 3c and 3d define the slit 3a with the adjacent wedge-wire portion which widens gradually radially inwardly of the screen, i.e., toward the inside of the screen.
  • the spiral wedge-wire 3 is welded at its inside apex 3e to the support rods 2.
  • the width of the slit 3a in the axial direction of the spiral wedge-wire 3 is so set that the width of the slit 3a at the same plane as the outer surface 3b of the spiral wedge-wire 3 will become smaller than the width of the outer surface 3b of the spiral wedge-wire 3.
  • the width of the spiral wedge-wire 3 is set at a proper value within the range from 0.1 mm to 3mm which is suitable for achieving the object of the well screen.
  • the skid rods 4 are made of linear steel rods of a wedge shape in cross section. As will be apparent from FIG. 2, the skid rods 4 are arranged in such a manner that their flat surface 4b face outside and the other two sides 4c and 4d define a space with the adjacent wedge-wire portion which widens gradually radially inwardly of the screen, i.e., toward the inside of the screen.
  • the spiral skid rods 4 are welded at their inside apex 4e to the flat outer surface 3b of the spiral wedge-wire 3.
  • the width of the slit 4a in the axial direction of the skid rods 4 is so set that the width of the slit 4a at the same plane as the outer surface 4b of the skid rods 4 will become smaller than the width of the outer surface 4b of the skid rods 4.
  • the width of the slit 4a of the skid rods 4 is set at a proper value within the range from 0.1mm to 3mm which is suitable for achieving the object of the well screen.
  • the skid rods 4 may be of other shape in cross section than the illustrated wedge-shape rods such, for example, as rods of a circular or polygonal shape in cross section. In any case, the interval between the adjacent skid rods is so set that it will become larger than the diameter of the skid rod.
  • FIG. 3 shows another embodiment of the invention with a part of the well screen cut off.
  • the same component elements as those of the embodiment of FIG. 1 are shown by the same reference characters as FIG. 1 and description thereof will be omitted.
  • the embodiment of FIG. 3 is a well screen made by welding skid rods on the outer surface of the protective frame of the well screen disclosed in U.S. Patent No. 5,311,942 (Japanese Patent No. 2891568) which is incorporated in this specification by reference.
  • a well screen 10 consists of a screen main body 11 and a protective frame 12.
  • the screen main body 11 includes a perforated pipe 13 perforated with a multiplicity of liquid taking openings 13a, a plurality of screen rods 14 provided on the outside of the perforated pipe 13, extending in the axial direction of the well screen 10 and arranged in the circumferential direction of the well screen 10 with an equal interval between respective adjacent screen rods, and a screen wire 15 wound spirally on the outside of the screen rods 14.
  • This screen main body 11 is of a well known structure in the field of oil wells.
  • a slit 15a having a predetermined width d is formed between respective wire portions which are adjacent to each other in the axial direction of the well screen 10.
  • the protective frame 12 includes a plurality of protective rods 16 arranged in the circumferential direction on the outside of the cylindrical screen wire 15 and extending in the axial direction of the well screen 10, annular rod holding members 17 holding the protective rods 16 at either end thereof and a protective wire 18 wound spirally on the outside of the protective rods 16.
  • Each protective rod 16 is fixed at both ends to the rod holding member 17 by means of welding or other means.
  • the protective wire 18 is welded to the protective rods 16 at each point of contact with the protective rods 16.
  • the protective wire 18 is provided for forming a grid-like structure with the protective rods 16, so that the pitch of the protective wire 18 will suffice if it is sufficient for mamtaining the strength for the purpose of the protective frame.
  • This gap g is determined at a proper value taking into account the diameter of the well, radius of curvature of the bent portion 100b of the well and other design conditions in such a manner that, in passing of the well screen 10 through the bent portion 100b, the bent screen wire 15 will not be brought into contact with the bent protective rods 16 or, even if the bent screen wire 15 is brought into contact with some of the bent protective rods 16, the screen wire 15 will not receive from the protective rods 16 an excessive load which will cause plastic deformation to the screen wire 15.
  • the annular rod holding members 17 are fixed to the screen rods 14 by suitable means such as welding in suitable locations between ends of a single well screen 10.
  • suitable means such as welding in suitable locations between ends of a single well screen 10.
  • a desired number of the annular rod holding members 17 can be disposed between the ends of a single well screen 10. Accordingly, by determining the interval between the respective annular rod holding members 17 at a sufficiently short distance, the respective screen rods 14 and the screen wire 15 in each section between the two adjacent annular rod holding members 17 are bent substantially uniformly in the bent portion 100b of the well and, as a result, the slit 15a of the screen wire 15 in the bent section of the screen undergoes substantially a uniform change.
  • FIG. 4 is a modification of the embodiment of FIG. 3.
  • the same component elements as those of the embodiment of FIG. 3 are designated by the same reference characters and description thereof will be omitted.
  • the perforated base pipe 13 of the embodiment of FIG. 3 is omitted but, if necessary, a similar perforated base pipe may be provided for reinforcement in this embodiment also..
  • a well screen 20 does not have the rod holding members 17 of the embodiment of FIG. 3 but protective rods 16 of a protective frame 12 are arranged at a predetermined interval on the outer surface of a screen wire 15 and a protective wire 18 is wound tightly on the outer surface of the protective rods 16.
  • the protective rods 16 are in pressed contact with the screen wire 15 by tight winding of the protective wire 18 on the protective rods 16 and, therefore, there is no gap between the protective rods 16 and the screen wire 15.
  • the embodiment of FIG 4 is the same as the embodiment of FIG. 3 in the other structure.
  • the skid rods 4 are welded to the outer surface of the protective wire 18 of the protective frame 12.
  • the screen rods 14 are made of wires having a circular cross section.
  • FIG. 5 shows another embodiment of the invention.
  • a well screen 30 comprises a perforated base pipe 28 perforated with a multiplicity of fluid taking openings 28a, support rods 2 extending in the axial direction of the screen 30 and arranged at a predetermined interval in the circumferential direction of the screen 30 on the outer surface of the perforated base pipe 28, a spiral wedge-wire 3 wound on the outer surface of the support rods 2 so as to form a slit 3a of a predetermined width, and a plurality of skid rods 4 made of metal rods extending in the axial direction of the screen 30, being arranged at a predetermined interval in the circumferential direction of the screen 30 and welded to a flat outer surface 3b of the spiral wedge- wire 3.
  • the well screen 30 is reinforced in its mechanical strength.
  • FIG. 6 shows another embodiment of the invention.
  • a well screen 40 comprises a wire-mesh 9 which is interposed as a filter member between a perforated base pipe 28 and support rods 2.
  • Other filter member such as a filter cloth or gravel may be used instead of a wire-mesh.
  • Other structure of this embodiment is the same as the embodiment of FIG. 5.
  • the width of the slit of the wedge-wire can be made a width which can prevent invasion of sand grains of a larger grain diameter and, as a result, quantity of oil flowing into the screen can be made larger while preventing invasion of sand grains. Further, since a wedge-wire of a larger diameter can be used by selecting a larger slit width, mechanical strength of the cylindrical screen can be improved to that degree.
  • the cylindrical well screen of the present invention can be utilized as a well screen for a horiontal or high-angle well, particularly a well screen for a horizontal or high-angle oil well.
  • the invention is capable of facilitating insertion of a cylindrical well screen into a horizontal or high-angle well and thereby shortening time required for inserting a well screen into a well.

Abstract

A cylindrical well screen (1) includes support rods (2) extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, a spiral wire (3) wound on the outer surface of the support rods (2) so as to form a slit (3a) of a predetermined width, and a plurality of skid rods (4) made of metal rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen. The skid rods (4) are welded to the outer surface (3b) of the spiral wire.(3).

Description

DESCRIPTION
Cyhndrical Well Screen Having Longitudinal Skid Rods
Technical Field
This invention relates to a well screen for a horizontal or high-angle well screen and, more particularly, to this type of well screen for a horizontal or high-angle oil well capable of facilitating insertion of this type of screen into the horizontal or high-angle well.
Background Art
There has recently been an increasing tendency in the field of a well for collecting crude oil to substituting a conventional vertical well formed by digging the ground vertically from the ground surface to the oil stratum by a horizontal or high-angle well. A sectional view of FIG.7A and a sectional view of FIG. 7B taken along arrows A - A of Fig. 7A show one of such horizontal or high- angle well which is formed by digging the ground from a vertical portion 100a through a curved portion 100b to a horizontal or inclined portion 100c which extends in the horizontal or inclined direction along the oil stratum. Since this type of horizontal or high- angle well has a screen section for collecting oil which is several times as long as a conventional vertical well, the horizontal or high- angle well has the advantage that it has a superior production efficiency which is several times as high as that of the vertical well.
Since a well screen is used in a well for allowing flow of crude oil into the screen while preventing invasion of sand, the well screen is required to have a slit having a size which is sufficient for preventing invasion of sand grains and, for this purpose, a spiral wire type screen is generally used as the well screen.
As the horizontal boring technique has recently been developed, there is an increasing tendency to increasing the length of the horizontal portion of the horizontal or high- angle well. In this case, a well screen is pushed into the well and is forced to move through the well by a long distance toward the horizontal portion of the well by bending the screen made of steel in the curved portion of the well, and by moving with the outer surface of the screen in factional contact with the wall 110 of the well-bore. This work for inserting the well screen into the well is a difficult one requiring tremendous working hours.
Since a slit of an accurate width is formed in the outermost spiral wire of a well screen, this slit tends to be damaged by being rubbed against the wall of the well-bore when the screen is inserted into the well. Besides, since the screen advances in the well in the direction crossing the direction in which the slit is formed, this enhances the damage to the slit.
Further, since the screen is inserted into the well with the spiral wire being in direct contact with the wall of the well-bore, fine sand grains of the wall of the well-bore are deposited on the slit of the spiral wire with the result that the slit of the spiral wire is blocked with the sand grains when insertion of the screen has been completed.
It is, therefore, an object of the invention to provide a cylindrical well screen capable of facilitating insertion of the well screen and thereby shortening the working time for inserting the well screen and preventing blocking or damage of the slit of the screen.
Disclosure of the Invention
For achieving the above described object of the invention, there is provided a cylindrical well screen comprising a plurality of skid rods made of metal extending in the axial direction of the screen, being arranged at a predetermined interval in the circumferential direction of the screen and welded to the outer surface of the screen.
According to the invention, the skid rods perform the function of a sledge for the screen during insertion of the well screen into the well and thereby decreasing friction between the outer surface of the well screen and the wall of the well-bore and, as a result, the screen can be inserted smoothly into the well and time required for inserting the well screen into the well can be shortened.
Further, since the skid rods protect the outermost spiral wire from the outside so that the spiral wire and its slit do not come into direct contact with the wall of the well-bore, damage of the slit due to contact with the wall of the well-bore can be prevented. Particularly in a bent portion of a horizontal well structure, the width of the slit in the top portion of the spiral wire tends to become small and the width of the slit in the bottom portion of the spiral wire tends to become large by bending of the screen with resulting deformation of the slit. According to the invention, since the skid rods are welded to the outer surface of the spiral wire in the axial direction of the well screen and, therefore, deformation of the slit can be prevented.
Furthermore, since the slit of the spiral wire does not come into direct contact with the wall of the well-bore during insertion of the well screen into the well, blocking of the slit due to fine sand grains of the wall of the well -bore during insertion of the well screen can be effectively prevented.
In one aspect of the invention, the well screen further comprises support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, and a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, said skid rods being welded to the outer surface of the spiral wire.
In another aspect of the invention, the well screen further comprises a screen wire and a protective frame, said protective frame comprising a plurality of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, a plurality of annular rod holding members provided at a predetermined interval in the axial direction of the screen for holding the protective rods, protective wire means provided about the protective rods in the circumferential direction of the screen, and a circumferential gap of a predetermined value, said gap being formed between the protective rods and the outer surface of the screen wire and extending longitudinally between the plurality of annular rod holding members, said skid rod being welded to the outer surface of the protective wire of the protective frame.
In another aspect of the invention, the well screen comprises a screen wire and a protective frame, said protective frame comprising a plurality of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen and protective wire means provided about the protective rods in the circumferential direction of the screen, said protective rods being in pressed contact with the screen wire by tight winding of the protective wire on the protective rods and the skid rods being welded to the outer surface of the protective wire of the protective frame.
In another aspect of the invention, the well screen further comprises a perforated base pipe perforated with a multiplicity of fluid taking openings, a plurality of support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen with a predetermined interval in the radial direction of the screen on the outside of the perforated base pipe so as to define an annulus between the perforated base pipe and the support rods, a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, and a filter member provided in the annulus between the perforated base pipe and the support rods, said skid rods being welded to the outer surface of the spiral wire.
Brief Description of the Drawings In the accompanying drawings,
FIG. 1 is a perspective view showing a preferred embodiment of the invention;
FIG. 2 is a perspective view showing a part of the embodiment in an enlarged scale! FIG. 3 is a perspective view showing another embodiment of the invention;
FIG. 4 is a perspective view showing another embodiment of the invention;
FIG. 5 is a perspective view showing another embodiment of the invention;
FIG. 6 is a perspective view showing another embodiment of the invention; and
FIGs. 7A and 7B are sectional views showing a horizontal well screen.
Best Mode for Carrying Out the Invention
Referring now to the accompanying drawings, embodiments of the present invention will be described.
FIG. 1 shows an embodiment of the cylindrical well screen having longitudinal skid rods made according to the present invention and FIG. 2 shows a part of the embodiment in an enlarged scale.
In this embodiment, a cylindrical well screen 1 comprises support rods 2 extending in the axial direction of the screen 1 and arranged at a predetermined interval in the circumferential direction of the screen 1, a spiral wedge-wire 3 wound on the outer surface of the support rods so as to form a slit 3a of a predetermined width, a plurality of skid rods 4 made of metal rods extending in the axial direction of the screen 1, being arranged at a predetermined interval in the circumferential direction of the screen 1 and welded to a flat outer surface 3b of the spiral wedge- wire 3. The support rods 2 support the spiral wedge-wire 3 and are made of steel rods having a circular cross section. The support rods 2 may be of other shape in cross section such as a polygonal shape. The support rods 2 are arranged generally cylindrically at a predetermined interval.
On the outer surface of the support rods 2 is wound the spiral wedge-wire 3 in the direction substantially crossing the support rods 2. As will be apparent from FIG. 2, the spiral wecge-wire 3 is arranged in such a manner that its flat surface 3b faces outside and the other two sides 3c and 3d define the slit 3a with the adjacent wedge-wire portion which widens gradually radially inwardly of the screen, i.e., toward the inside of the screen. The spiral wedge-wire 3 is welded at its inside apex 3e to the support rods 2. The width of the slit 3a in the axial direction of the spiral wedge-wire 3 is so set that the width of the slit 3a at the same plane as the outer surface 3b of the spiral wedge-wire 3 will become smaller than the width of the outer surface 3b of the spiral wedge-wire 3. The width of the spiral wedge-wire 3 is set at a proper value within the range from 0.1 mm to 3mm which is suitable for achieving the object of the well screen.
In the illustrated example, the skid rods 4 are made of linear steel rods of a wedge shape in cross section. As will be apparent from FIG. 2, the skid rods 4 are arranged in such a manner that their flat surface 4b face outside and the other two sides 4c and 4d define a space with the adjacent wedge-wire portion which widens gradually radially inwardly of the screen, i.e., toward the inside of the screen. The spiral skid rods 4 are welded at their inside apex 4e to the flat outer surface 3b of the spiral wedge-wire 3. The width of the slit 4a in the axial direction of the skid rods 4 is so set that the width of the slit 4a at the same plane as the outer surface 4b of the skid rods 4 will become smaller than the width of the outer surface 4b of the skid rods 4. The width of the slit 4a of the skid rods 4 is set at a proper value within the range from 0.1mm to 3mm which is suitable for achieving the object of the well screen.
The skid rods 4 may be of other shape in cross section than the illustrated wedge-shape rods such, for example, as rods of a circular or polygonal shape in cross section. In any case, the interval between the adjacent skid rods is so set that it will become larger than the diameter of the skid rod.
FIG. 3 shows another embodiment of the invention with a part of the well screen cut off. In this and subsequent embodiments, the same component elements as those of the embodiment of FIG. 1 are shown by the same reference characters as FIG. 1 and description thereof will be omitted. The embodiment of FIG. 3 is a well screen made by welding skid rods on the outer surface of the protective frame of the well screen disclosed in U.S. Patent No. 5,311,942 (Japanese Patent No. 2891568) which is incorporated in this specification by reference.
In the embodiment of FIG. 3, a well screen 10 consists of a screen main body 11 and a protective frame 12. The screen main body 11 includes a perforated pipe 13 perforated with a multiplicity of liquid taking openings 13a, a plurality of screen rods 14 provided on the outside of the perforated pipe 13, extending in the axial direction of the well screen 10 and arranged in the circumferential direction of the well screen 10 with an equal interval between respective adjacent screen rods, and a screen wire 15 wound spirally on the outside of the screen rods 14. This screen main body 11 is of a well known structure in the field of oil wells. A slit 15a having a predetermined width d is formed between respective wire portions which are adjacent to each other in the axial direction of the well screen 10. The protective frame 12 includes a plurality of protective rods 16 arranged in the circumferential direction on the outside of the cylindrical screen wire 15 and extending in the axial direction of the well screen 10, annular rod holding members 17 holding the protective rods 16 at either end thereof and a protective wire 18 wound spirally on the outside of the protective rods 16. Each protective rod 16 is fixed at both ends to the rod holding member 17 by means of welding or other means. The protective wire 18 is welded to the protective rods 16 at each point of contact with the protective rods 16. The protective wire 18 is provided for forming a grid-like structure with the protective rods 16, so that the pitch of the protective wire 18 will suffice if it is sufficient for mamtaining the strength for the purpose of the protective frame.
There is provided a gap g of a predetermined value between the respective protective rods 16 and the outer surface of the screen wire 15. This gap g is determined at a proper value taking into account the diameter of the well, radius of curvature of the bent portion 100b of the well and other design conditions in such a manner that, in passing of the well screen 10 through the bent portion 100b, the bent screen wire 15 will not be brought into contact with the bent protective rods 16 or, even if the bent screen wire 15 is brought into contact with some of the bent protective rods 16, the screen wire 15 will not receive from the protective rods 16 an excessive load which will cause plastic deformation to the screen wire 15.
In the illustrated embodiment, the annular rod holding members 17 are fixed to the screen rods 14 by suitable means such as welding in suitable locations between ends of a single well screen 10. By fixing the annular rod holding members 17 to the screen rods 14, a desired number of the annular rod holding members 17can be disposed between the ends of a single well screen 10. Accordingly, by determining the interval between the respective annular rod holding members 17 at a sufficiently short distance, the respective screen rods 14 and the screen wire 15 in each section between the two adjacent annular rod holding members 17 are bent substantially uniformly in the bent portion 100b of the well and, as a result, the slit 15a of the screen wire 15 in the bent section of the screen undergoes substantially a uniform change. Consequently, in the illustrated embodiment in which a desired number of the annular rod holding members 17 can be disposed between the ends of a single screen 10, there is less likelihood of occurrence of irregularity in the slit width d of the screen wire 15 in the bent section of the screen 10 than in the case where the annular rod holding members 17 are provided only at the two ends of a single screen 10.
In this embodiment, the skid rods 4 extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen are welded to the outer surface of the protective wire 18 of the protective frame 12. FIG. 4 is a modification of the embodiment of FIG. 3. In the embodiment of FIG. 4, the same component elements as those of the embodiment of FIG. 3 are designated by the same reference characters and description thereof will be omitted.
In the embodiment of FIG. 4, the perforated base pipe 13 of the embodiment of FIG. 3 is omitted but, if necessary, a similar perforated base pipe may be provided for reinforcement in this embodiment also..
In the embodiment of FIG. 4, a well screen 20 does not have the rod holding members 17 of the embodiment of FIG. 3 but protective rods 16 of a protective frame 12 are arranged at a predetermined interval on the outer surface of a screen wire 15 and a protective wire 18 is wound tightly on the outer surface of the protective rods 16. The protective rods 16 are in pressed contact with the screen wire 15 by tight winding of the protective wire 18 on the protective rods 16 and, therefore, there is no gap between the protective rods 16 and the screen wire 15. The embodiment of FIG 4 is the same as the embodiment of FIG. 3 in the other structure. The skid rods 4 are welded to the outer surface of the protective wire 18 of the protective frame 12. In the embodiment of FIG. 4, the screen rods 14 are made of wires having a circular cross section. FIG. 5 shows another embodiment of the invention. In the embodiment of FIG. 5, a well screen 30 comprises a perforated base pipe 28 perforated with a multiplicity of fluid taking openings 28a, support rods 2 extending in the axial direction of the screen 30 and arranged at a predetermined interval in the circumferential direction of the screen 30 on the outer surface of the perforated base pipe 28, a spiral wedge-wire 3 wound on the outer surface of the support rods 2 so as to form a slit 3a of a predetermined width, and a plurality of skid rods 4 made of metal rods extending in the axial direction of the screen 30, being arranged at a predetermined interval in the circumferential direction of the screen 30 and welded to a flat outer surface 3b of the spiral wedge- wire 3. By the provision of the perforated base pipe 28, the well screen 30 is reinforced in its mechanical strength.
FIG. 6 shows another embodiment of the invention. In this embodiment, a well screen 40 comprises a wire-mesh 9 which is interposed as a filter member between a perforated base pipe 28 and support rods 2. Other filter member such as a filter cloth or gravel may be used instead of a wire-mesh. Other structure of this embodiment is the same as the embodiment of FIG. 5.
In the structure in which a filter member such as a wire-mesh, filter cloth or gravel is interposed between the perforated base pipe 28 and the support rods 2, by selecting a proper filter member so that invasion of sand grains having the minimum grain diameter in sand grains of the oil stratum can be prevented by the filter member, the width of the slit of the wedge-wire can be made a width which can prevent invasion of sand grains of a larger grain diameter and, as a result, quantity of oil flowing into the screen can be made larger while preventing invasion of sand grains. Further, since a wedge-wire of a larger diameter can be used by selecting a larger slit width, mechanical strength of the cylindrical screen can be improved to that degree.
Industrial Apphcability
The cylindrical well screen of the present invention can be utilized as a well screen for a horiontal or high-angle well, particularly a well screen for a horizontal or high-angle oil well. The invention is capable of facilitating insertion of a cylindrical well screen into a horizontal or high-angle well and thereby shortening time required for inserting a well screen into a well.

Claims

1. A cylindrical well screen comprising a plurahty of skid rods made of metal extending in the axial direction of the screen, being arranged at a predetermined interval in the circumferential direction of the screen and welded to the outer surface of the screen.
2. A well screen as defined in claim 1 further comprising support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, and a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, said skid rods being welded to the outer surface of the spiral wire.
3. A well screen as defined in claim 1 further comprising a screen wire and a protective frame, said protective frame comprising a plurahty of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen, a plurahty of annular rod holding members provided at a predetermined interval in the axial direction of the screen for holding the protective rods, protective wire means provided about the protective rods in the circumferential direction of the screen, and a circumferential gap of a predetermined value, said gap being formed between the protective rods and the outer surface of the screen wire and extending longitudinally between the plurahty of annular rod holding members, said skid rod being welded to the outer surface of the protective wire of the protective frame.
4. A well screen as defined in claim 1 further comprising a screen wire and a protective frame, said protective frame comprising a plurahty of protective rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen and protective wire means provided about the protective rods in the circumferential direction of the screen, said protective rods being in pressed contact with the screen wire by tight winding of the protective wire on the protective rods and the skid rods being welded to the outer surface of the protective wire of the protective frame.
5. A well screen as defined in claim 1 further comprising a perforated base pipe perforated with a multiphdty of fluid taking openings, a plurahty of support rods extending in the axial direction of the screen and arranged at a predetermined interval in the circumferential direction of the screen with a predetermined interval in the radial direction of the screen on the outside of the perforated base pipe so as to define an annulus between the perforated base pipe and the support rods, a spiral wire wound on the outer surface of the support rods so as to form a slit of a predetermined width, and a filter member provided in the annulus between the perforated base pipe and the support rods, said skid rods being welded to the outer surface of the spiral wire.
PCT/JP2003/004801 2002-04-26 2003-04-16 Cylindrical well screen having longitudinal skid rods WO2003091536A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003230239A AU2003230239A1 (en) 2002-04-26 2003-04-16 Cylindrical well screen having longitudinal skid rods

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002125383A JP2003314184A (en) 2002-04-26 2002-04-26 Cylindrical screen for well, having longitudinal skid rods
JPNO.2002-125383 2002-04-26

Publications (1)

Publication Number Publication Date
WO2003091536A1 true WO2003091536A1 (en) 2003-11-06

Family

ID=29267561

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2003/004801 WO2003091536A1 (en) 2002-04-26 2003-04-16 Cylindrical well screen having longitudinal skid rods

Country Status (3)

Country Link
JP (1) JP2003314184A (en)
AU (1) AU2003230239A1 (en)
WO (1) WO2003091536A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004111384A1 (en) 2003-06-17 2004-12-23 Completion Products Pte Ltd A well screen
EP1818089A1 (en) * 2006-02-01 2007-08-15 Weatherford/Lamb, Inc. Helical internal support structure for intake screens
US9399858B2 (en) 2011-08-30 2016-07-26 Bilfinger Water Technologies, Inc. Hybrid intake screen assembly
CN110740797A (en) * 2017-04-13 2020-01-31 阿奎塞腾斯集团有限公司 Wire mesh filter for microfiltration

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100838839B1 (en) * 2001-12-22 2008-06-17 주식회사 포스코 Coke crushing system
US7086283B2 (en) 2004-07-15 2006-08-08 Riken Keiki Co., Ltd. Explosion-proof portable gas detector
JP5920562B2 (en) * 2011-11-11 2016-05-18 株式会社ナガオカ Intake well intake structure
KR101648738B1 (en) * 2016-05-09 2016-08-17 주식회사 윌스크린 Screen and catridge type screening appapatus having the same
JP7137822B2 (en) * 2018-05-23 2022-09-15 アクセプタンスジャパン株式会社 Screen manufacturing method and screen

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4657079A (en) * 1980-12-11 1987-04-14 Nagaoka Kanaai Kabushiki Kaisha Screen
US4818403A (en) * 1985-12-27 1989-04-04 Nagaoka Kanaami Kabushiki Kaisha Double cylinder screen
EP0547865A2 (en) * 1991-12-16 1993-06-23 Halliburton Company Well screen with prepacked screen element
US5311942A (en) * 1991-08-09 1994-05-17 Nagaoka International Corporation Well screen having a protective frame for a horizontal or high-angle well
US5339895A (en) * 1993-03-22 1994-08-23 Halliburton Company Sintered spherical plastic bead prepack screen aggregate
EP0622523A2 (en) * 1993-04-30 1994-11-02 Nagaoka International Corporation Well screen having a slurry flow path
EP0659975A2 (en) * 1993-12-02 1995-06-28 Nagaoka International Corporation Well screen having a uniform outer diameter
EP0674095A2 (en) * 1994-03-11 1995-09-27 Nagaoka International Corporation Well screen with coiled element
US20020038707A1 (en) * 2000-09-29 2002-04-04 United States Filter Corporation Well screen

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4657079A (en) * 1980-12-11 1987-04-14 Nagaoka Kanaai Kabushiki Kaisha Screen
US4818403A (en) * 1985-12-27 1989-04-04 Nagaoka Kanaami Kabushiki Kaisha Double cylinder screen
US5311942A (en) * 1991-08-09 1994-05-17 Nagaoka International Corporation Well screen having a protective frame for a horizontal or high-angle well
EP0547865A2 (en) * 1991-12-16 1993-06-23 Halliburton Company Well screen with prepacked screen element
US5339895A (en) * 1993-03-22 1994-08-23 Halliburton Company Sintered spherical plastic bead prepack screen aggregate
EP0622523A2 (en) * 1993-04-30 1994-11-02 Nagaoka International Corporation Well screen having a slurry flow path
EP0659975A2 (en) * 1993-12-02 1995-06-28 Nagaoka International Corporation Well screen having a uniform outer diameter
EP0674095A2 (en) * 1994-03-11 1995-09-27 Nagaoka International Corporation Well screen with coiled element
US20020038707A1 (en) * 2000-09-29 2002-04-04 United States Filter Corporation Well screen

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004111384A1 (en) 2003-06-17 2004-12-23 Completion Products Pte Ltd A well screen
EP1644610B1 (en) * 2003-06-17 2018-09-26 Completion Products Pte Ltd A well screen
EP1818089A1 (en) * 2006-02-01 2007-08-15 Weatherford/Lamb, Inc. Helical internal support structure for intake screens
AU2007200277B2 (en) * 2006-02-01 2009-01-08 Weatherford/Lamb, Inc. Helical internal support structure for intake screens
US7950527B2 (en) 2006-02-01 2011-05-31 Weatherford/Lamb, Inc. Helical internal support structure for intake screens
US8292089B2 (en) 2006-02-01 2012-10-23 Weatherford/Lamb, Inc. Helical support structure for intake screens
US9399858B2 (en) 2011-08-30 2016-07-26 Bilfinger Water Technologies, Inc. Hybrid intake screen assembly
US10399013B2 (en) 2011-08-30 2019-09-03 Aqseptence Group, Inc. Hybrid intake screen assembly
US11331603B2 (en) 2011-08-30 2022-05-17 Aqseptence Group, Inc. Hybrid intake screen assembly
CN110740797A (en) * 2017-04-13 2020-01-31 阿奎塞腾斯集团有限公司 Wire mesh filter for microfiltration
EP3609596A4 (en) * 2017-04-13 2021-01-06 Aqseptence Group, Inc. Screen filter for microfiltration

Also Published As

Publication number Publication date
JP2003314184A (en) 2003-11-06
AU2003230239A1 (en) 2003-11-10

Similar Documents

Publication Publication Date Title
EP0527426B1 (en) Well screen having a protective frame for a horizontal or high-angle well
US4657079A (en) Screen
US5738170A (en) Compact double screen assembly
US6382318B1 (en) Filter for subterranean use
AU691860B2 (en) Coiled well screen
RU2074313C1 (en) Filter insulated in selective manner
EP0547865B1 (en) Well screen with prepacked screen element
EP0819831A1 (en) Screen for use in a well
WO2003091536A1 (en) Cylindrical well screen having longitudinal skid rods
IE46407B1 (en) Protected well screen
US6298914B1 (en) Wire-wrapped well screen
EP0548903B1 (en) Method of manufacturing a selective isolation screen
JPS60244315A (en) Cylindrical screen and preparation thereof
WO2003091535A1 (en) Sand screen having a multiple welded wedge-wire structure
RU2147676C1 (en) Well strainer and method of its manufacture
WO2000047867A1 (en) Sandfilter device for use in the recovery of oil, gas and water
AU7042194A (en) Sand screen structure
US4249292A (en) Method of assembling self-cleaning helical spring filter
EP0309186A1 (en) Improved helically wound screen and method of making the same
US4277348A (en) Methods for cleaning a helical spring filter
CN213205636U (en) Variable-precision wire-wound sieve tube
JP3440142B2 (en) Screen joint structure

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PH PL PT RO RU SC SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase