TUBE SEALING DEVICE AND A SEALING ELEMENT FOR SUCH A DEVICE

Abstract

Device for sealing a leakage in a well tube, comprising a sealing ring and elements for forcing the sealing ring into sealing engagement with the wall of the tube. A power device being operatively connected to the elements. The sealing ring having beveled ends which are juxtaposed with a pair of mating conical rings. A cylinder-piston device engages the conical rings to force them into expanding engagement with the sealing ring.

Description

The invention relates to a well tube sealing device, particularly for sealing a leakage in a well bore tubing, and a sealing element for sealing such a leakage.

BACKGROUND OF THE INVENTION

When an opening is formed in the sidewalls of an existing wellbore casing, whether through damage to the casing or because of an intentional perforation of the casing to facilitate production or a fracturing operation, it may be necessary to seal off the opening in the existing wellbore casing. Conventional methods for sealing off such openings are expensive and unreliable.

In U.S. Pat. No. 7,048,067 (Cook et al 2006) a wellbore casing repair is shown, where an expandable sealing member is radially expanded by two expansion cones forced together in the sealing zone.

With a sealing member according to this prior art, made of a polymer, there will be no satisfying and lasting sealing.

OBJECTS OF THE INVENTION

The main object of the invention is to provide a device and a sealing element which can provide a lasting and secure sealing for any leakage in a well bore tubing and a similar structure with high temperatures and high pressures.

A further object is to provide a device and sealing element which is easy to install and bring in a lasting position.

Further it is an object to provide a sealing element which can be applied universally in metal tubing.

THE INVENTION

The basic features of the Invention are stated in claim 1. This device may be used for sealing various tubular structures with corresponding requirements in addition to well tubes. Further details of the invention are listed in the sub claims 2 to 6 to claim 1 and subclaims 8 and 9 to claim 7. Further details regarding the invention will appear from the sub claims to the claims 6 and 7.

EXAMPLE

The invention is illustrated in the drawings, in which

FIGS. 1 and 2 are showing a longitudinal section of a tube with a sealing ring assembly in an insertion position and a sealing position respectively,

FIGS. 3 and 4 are a longitudinal cross section showing a sealing ring setting assembly carrying the sealing ring assembly of FIGS. 1 and 2 respectively, while

FIG. 5 is showing a detail from FIG. 2.

The elements of the Figures are shown with a vertical axis. The invention is however suitable for any position of the tube or bore to be sealed.

In FIGS. 1 and 2 an example of an embodiment of the invention is shown at an oil well tube 11, which may have a leakage fissure 12. A sealing ring assembly 13 is shown without a setting assembly, which is shown in FIGS. 3 and 4. “Sealing ring assembly” is comprising a sealing ring and its integrated expanding elements as will be described.

The sealing ring assembly 13 is shown in its start position in FIG. 1, lacking the setting assembly, which is provided as a part of the total arrangement before immersion into the oil well tube 11. In FIG. 2, the setting assembly has been removed after finished setting of the sealing ring assembly. This is the state of operation for the sealing ring assembly.

The sealing ring assembly 13 consists of a sealing ring 14 with an outer sealing face 15 and inner beveled ends 16, 17, shown particularly in FIG. 5. The outer sealing face 15 is cylindrical with a low bead 18, 19 at each end, centrally to the beveled ends 16, 17. The beads 18, 19 have the function of providing an annular area of particular trust against the wall 20 of the oil well tube 11. The outer face 15 of the sealing ring 14 is covered by a layer 21 of a material with a higher ductility than the base material of the sealing ring, which may be steel or another alloy with corresponding strength properties. The layer 21 may be of silver, or of a resin material.

The sealing ring assembly 13 further comprises a pair of expanding dies 22, 23 which generally consist of a pair of conically beveled press rings 24, 25 facing the beveled ends 16, 17 of the sealing ring 14 and being integrated with a pair of tapering bushings 26, 27 which are overlapping with mutual engagement in a grip zone 28. In the grip zone, both bushings 26, 27 have a knurled surface for interlocking the expanding dies 22, 23 in the final, compressed position shown in FIG. 2.

The expanding die 22 facing the accessible end of the tube 11 has an annular, radially extending rim 29 for engaging the setting assembly shown in FIGS. 3 and 4. The opposite expanding die 23 has a radial groove 30 at the outer end for receiving a shear off ring 31 of a soft metallic material, e.g. copper. To lock the shear ring 31 in the groove 30, a locking ring 32 is inserted into a second, inner groove 33. The shear off ring 31 has an axial groove 34 for making a weakened area.

FIGS. 3 and 4 show a setting assembly 35 provided for engaging the expanding dies 22, 23 during the setting stage, to expand the sealing ring 14 into sealing engagement with the oil well tube. The setting assembly is shown together with the sealing ring assembly in an initial position in FIG. 3, and in an intermediate position shortly before breaking the shear ring 31 in FIG. 4.

The setting assembly 35 comprises as main element a cylinder piston device 36. The cylinder piston device 36 has a tubular element 37, the cylindrical outside of which is carrying an annular glider or piston 38. The annular piston 38 has a collar 39 sliding on a locking ring 40 acting as a locking nut on the tubular element 37 at the free end thereof,

The collar 39 of the piston 38 is carrying the shear ring 31, this being locked with a locking sleeve 41 acting as a locking nut.

The tubular element 37 centrally in the setting assembly 35 is carried by an end dish 42 on which the rim 29 is engaging an annular step 43. The end dish 42 has a lug 44 with an opening 45 for connecting to an arm for positioning the complete sealing device in the oil well tube 11.

The tubular element 37 has a cylindrical insert 46 in the free end, with a pair of sealing rings 47, 48 in circumferential grooves and threads 40 at the outer end. The cylindrical insert 46 is providing a manifold for connecting the cylinder-piston-arrangement to an external hydraulic system. At the inner end of the cylindrical insert 46 is a cylindrical recess 52 with a threaded bottom bore 50 can take a hose coupling (not shown). An opening 51 in the end dish 42 being provided for a hose.

The cylindrical insert 45 has a connecting channel 53 to provide hydraulic medium to the chamber 54 of the piston 38.

Setting the Sealing Ring.

The sealing ring assembly 13 with the setting assembly 35 incorporated is lowered into a well bore tube 11 as shown in FIG. 1. At the level of the leakage 12, the sealing ring assembly is positioned for setting. By supplying high pressure hydraulic medium to the setting assembly, the expanding dies 22, 23 are contracted and are pressing the sealing ring 14 against the wall 20 of the well bore tube 11, and deforming the beads or annular ribs 18 and 19 to provide a particular tight fit on both sides of the leakage 12.

To have a defined upper setting force, the copper ring 31 is designed to be torn off at a certain strain. The tearing properties of copper are suitable for the present purpose, as the shearing ring will have a certain duration, giving no shock in the system. Alternatively to the copper ring 31, a ring of a different material with predictable rupturing properties can be used.

After tearing off the copper ring 31, the inner part of the setting assembly may be detracted from the oil well tube 11 and recovered, while the sealing ring assembly 13 is left with an opening 54. One part of the ring will remain together with the sealing ring assembly 13, while the other part will remain on the sealing ring setting assembly 35.

The invention may be utilized for providing sealing rings in tubes or tubular openings different from that of an oil well tube.

Claims

1. Device for sealing a leakage (12) in a well tube (11), comprising a sealing ring (14) and elements (22-25) for forcing the sealing ring into sealing engagement with the wall (20) of the tube (11), a power device (35; 38) being operatively connected to said elements (22-25), wherein the sealing ring (14) has beveled inner ends (18, 19) which are juxtaposed with a pair of mating conical rings (24, 25), and that a cylinder-piston-device (36) is engaging the conical rings (24, 25) for forcing them into substantially non-elastic engagement with the sealing ring (14).

2. Device according to claim 1, wherein the conical rings (24, 25) engaging the ends (18, 19) of the sealing ring (14) are connected by a mating pair of sleeves ( ) which are engaging in a beveled area for providing a locking mesh.

3. Device according to claim 1, wherein the conical rings (24, 25) are engaged by a centrally arranged cylinder-piston arrangement (35), to be pressed axially to an expanding engagement with the sealing ring (14),

4. Device according to claim 3, wherein it comprises an annular piston (38) sliding on a central, tubular core (37), the piston and the core being connected to a pair of cooperating rings (39A, 43) provided to press against the ends of the conical rings (24, 25) for expanding the sealing ring (14).

5. Device according to claim 4, wherein the engagement against one of the conical rings (24, 25) is provided by a rupturable ring (31) of a material having a defined shear strength, preferably copper.

6. Device according to claim 1, wherein the cylinder-piston arrangement (36) is included in a sealing ring setting assembly (35) with a central connection (50, 51, 52) to an external hydraulic system.

7. Sealing element (14) for sealing a leakage in a tube (11), with an annular outer face provided to engage the inner wall of a tube to be sealed, wherein the outer face of the sealing ring has two annular beads (18, 19) in the core material of the sealing ring.

8. Sealing element according to claim 7, wherein the height of the annular beads (18, 19) is ca. 0.8-2 mm.

9. Sealing ring according to claim 7, wherein at least the outer surface of the beads (18, 19) is covered with a layer of a ductile material, as silver, gold, lead, or plastic, preferably the outer face of the sealing ring, is covered by the sealing layer.