US 3349852 A
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31, 1,967 B. A. PETERS APPARATUS FOR REPAIRING PIPE STRINGS Filed NOV. 16, 1965 FIG. --3
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ATTORNEY United States Patent 3,349,852 APPARATUS FOR REPAIRING PIPE STRINGS Beidon A. Peters, Houston, Tex., assignor to Esso Production Research Company, a corporation of Delaware Filed Nov. 16, 1965, Ser. No. 508,104 Claims. (Cl. 166-413) The present invention relates to apparatus for repairing pipe strings and is particularly concerned with a device for sealing holes in oil well tubing, casing and similar tubular goods.
The tubular goods used in oil wells, gas wells and similar boreholes often develops leaks due to corrosion, sand blasting or excessive pressure. In most cases these leaks occur at points where the pressure inside the tubing or casing is greater than that outside. This permits the escape of fluids from the pipe string containing the leak into the space surrounding it. It has been suggested that such leaks be repaired by means of sleeves which can be expanded against the inner wall of the tubing or casing and held in place with an epoxy resin or similar material. Experience has shown that this method of repair is not always satisfactory and that in many cases it is necessary to kill the well, remove the pipe string, and replace the damaged portion. This procedure is expensive and time consuming, particularly in deep wells and at offshore installations where workover equipment may not be readily available.
The present invention provides improved apparatus for plugging leaks to prevent the escape of fluids from the tubing or casing in oil wells and similar boreholes. This apparatus includes an elongated tool which can be lowered into the wellbore at the end of a wireline, cable or other supporting member. Segmental patches having outer radii corresponding to the internal radius of the tubing or casing and provided with elastic gaskets or similar sealing means bonded to the outer periphery of each patch are mounted on the tool body. An orienting section having elongated vanes aligned with the patches extends adjacent the body. The orienting section causes the apparatus to rotate in the vicinity of the leak until one of the patches is properly aligned with the hole through which leakage is taking place. Fluids flowing toward the hole force the apparatus into position so that the patch extends over and seals the leak. Differential pressure then holds the patch in place. By mainpulating the wireline or cable at the surface or using jars, the patch can be disengaged from the tool to permit withdrawal of the apparatus from the wellbore. Tests have shown that the use of this apparatus provides an inexpensive and highly effective means for patching leaks that are difiicult to repair by other methods.
The nature and objects of the invention can best 'be understood by referring to the following detailed description of a preferred embodiment of the apparatus and to the accompanying drawing, in which:
FIG. 1 is a vertical section through a wellbore showing the apparatus of the invention in place adjacent a hole in the casing wall;
FIG. 2 is a cross-section through the apparatus of FIG. 1 taken about the line 2-2;
FIG. 3 is a cross-section through the casing following removal of the tool from the wellbore; and
FIG. 4 is a cross-section to the tool of FIG. 1 taken about the line 4-4.
The apparatus shown in FIG. 1 of the drawing includes a string of easing or tubing 11 which extends vertically in an oil well or similar borehole. The pipe string contains a hole 12 through which fluids tend to escape outwardly into the space surrounding the string in response to diiferential pressure. A patching tool for repairing the leak is suspended in the pipe string adjacent hole 12 by means of a wireline 13. The wireline is attached to the upper end 3,349,852 Patented Oct. 31, 1967 of the tool by means of a socket 14 of conventional design. Jars of conventional design may be provided above the tool if desired. Below the socket, the tool is preferably provided with a shank 15 or smaller diameter which will facilitate recovery in the event the apparatus is lost in the wellbore. Body 16 extends below the upper shank to a supporting section 17, shown more clearly in FIG. 2 of the drawing. The cross-sectional configuration of the supporting section is not critical and may be circular as shown or noncircular. Segmental plates or patches 18 are attached to the supporting section of the tool body by means of shear pins or similar members 19. The shear pins are designed so that they are capable of supporting the weight of the patches but will fail under a predetermined shear loading. The tool shown includes four patches spaced at intervals but a greater or lesser number may be provided if desired.
Each patch extends parallel to the longitudinal axis of the tool and has an outside radius approximately the same as the inside radius of pipe string 11. The patches may be made of steel or other metal or from plastic laminates or other nonmetallic materials of suflicienlt strength to withstand the stresses to which the patch will normally be subjected. Where corrosion is apt to be a problem, the use of corrosion-resistant or nonmetallic patches is preferred. A gasket 20 of rubber or similar resilient material extends about the periphery of each plate to provide a leak tight seal between the patch and the adjacent pipe wall. The patch provides a large area on which the differential pressure is exerted, thereby providing sufiicient force to hold the patch in place over hole 12. The shear strength of the pins 19 should be less than the force required to dislodge the patch after it has been positioned over a hole in the pipe. This force will depend in part upon the size of the patch and the difierential pressure across the hole and can be readily calculated. The force necessary to hold the patch on the tool is small and hence pins or similar members of small diameter will normally be satisfactory.
The orienting section of the tool shown as in the drawing is located below the supporting section 17 but can be placed above the supporting section if desired. It includes concave plates 22. These plates, shown in cross-section in FIG. 4, are welded, bolted or otherwise attached to lower body section 21 below the supporting section. The longitudinal axis of each plate extends parallel to the longitudinal axis of the tool. It is generally preferred that each plate curve inwardly toward lower body section 21 to form a continuous are as shown. The combined plates thus form four vanes spaced 90 apart. Each of these vanes extends vertically along the center line of one of the segmental patches. The diameter of the lower section of the tool through the vane is substantially the same :as the diameter through the plates composing the vanes. It is preferred that the length of the lower section containing the vanes be form about 15 to about 25 times the major diameter of the lower section. The lower end of each vane is tapered as indicated by reference numeral 23 to facilitate lowering of the apparatus past joints in the pipe.
The orienting section of the tool is not limited to the particular structure shown in the drawing. In lieu of the curved plates depicted, each vane may consist of a sheet of metal, plastic or the like extending radially from lower body section 21 or a similar supporting member. The orienting section can also be constructed from crossshaped extruded metals or plastics or formed by bending or joining sheets of metal or the like to produce a diamond shaped cross-section having a vane extending at each corner. The number of vanes provided will depend, of course, on the number of patches mounted on the tool above the orienting section. Each vane will normally be located on the center line of a patch above or below the patch. The vanes may extend outwardly to points adjacent the outer surfaces of the patches or may instead be of smaller diameter than the section of the tool containing the patches.
In utilizing the apparatus of the invention, the tool is first lowered into the pipe string containing the leak by means of a wire line or similar supporting member which will permit its rotation. A swivel connection may be provided between the lower end of the supporting member and the upper end of the tool to facilitate rotation if desired. As the orienting section at the bottom end of the device reaches a level in the pipe string at which the leak is located, the forces exerted on the vanes by water, oil, gas or other fluids flowing toward the leak cause the tool to move laterally toward the leak and to rotate until one vane is substantially aligned with the hole in the pipe. When the tool is in this position, one of the patches is located directly above the hole. As the apparatus is lowered farther, the moving fluids force the tool against the pipe wall so that the patch covers the opening therein and shuts off fluid flow. Differential pressure on the patch prevents it from being dislodged. The Wireline or other supporting member is then pulled or manipulated from the surface to shear the pins holding the patch in place on the tool body. Once this has been done, the tool can be withdrawn from the wellbore. The patch remains in place over the hole in the pipe as shown in FIG. 3 of the drawing. As long as the fluids in the pipe exert sufficient hydrostatic force or pressure to retain the patch, no further leakage will occur. Because the patch occupies little space within the pipe string, the flow of fluids through the pipe is not significantly restricted. Wireline instruments of various types can be raised and lowered past the patch without difficulty.
What is claimed is:
1. A tool for repairing a conduit containing a hole in the conduit wall through which fluid escapes comprising:
(a) an elongated body member;
(b) a plurality of patches detachably mounted on said body member about the periphery thereof, each of said patches having an outer radius of curvature substantially corresponding to the inner radius of curvature of said conduit and each patch including means for effecting a seal on contact of said patch with the wall of said conduit;
(0) means for moving said tool axially within said conduit; and,
(d) means for orienting said tool with respect to said hole in said conduit in response to fluid flow through said hole and thereby aligning one of said patches on said tool with said hole.
2. A tool as defined by claim 1 wherein said means for effecting a seal includes an elastic sealing member about the periphery of each patch.
3. A tool as defined by claim 1 wherein said means for orienting said tool includes a plurality of vanes near one end of the tool, each of said vanes being substantially aligned with the centerline of a patch and each vane extending parallel to the longitudinal axis of said tool.
4. A tool as defined by claim 1 wherein said patches are mounted on said body member by means of shear pins.
5. A tool as defined by claim 3 wherein the length of said vanes is from about 15 to about 25 times the tool diameter through said vanes.
6. A tool as defined by claim 1 wherein said patches are metallic plates.
7. A tool as defined by claim 3 wherein each of said vanes is formed by two concave plates joined at their outer ends.
8. A tool as defined by claim 1 wherein said patches are nonmetallic.
9. A tool as defined by claim 3 wherein said vanes are located near the lower end of said tool.
10. A tool as defined by claim 1 including four patches spaced at intervals.
References Cited UNITED STATES PATENTS 1,180,714 4/1916 Hall 13897 1,880,218 10/1932 Simmons 166-207 X 1,928,542 9/1933 Reiterer 138-97 2,187,275 1/1940 MCLennan 166113 2,672,162 3/1954 Brauer 13897 3,144,880 8/1964 Witska 13897 CHARLES E. OCONNELL, Primary Examiner.
DAVID H. BROWN, Examiner.