Junk catcher and a method of operation of same

Abstract

This invention relates to a junk catcher (2, 2′) releasably connected to a retrievable bridge plug (4, 4′) connectable to a setting tool (6) for joint deployment of bridge plug (4, 4′) and junk catcher (2, 2′) in a borehole (9) or a tubular in the borehole (9). Setting tool (6) extends through a fishing neck (12), a catcher tube (14), a flanged section (16), a valve chamber (18), a closable opening (20) and a portion of a setting sleeve (22, 22′) of junk catcher (2, 2′). Valve chamber (18) comprises a valve (50) arranged to close closable opening (20) after retrieval of setting tool (6) from junk catcher (2, 2′). The junk catcher (2, 2′) is connected to bridge plug (4, 4′) by at least one shear bolt (27, 38). Bridge plug (4,4′) comprises a plug fishing neck (32, 32′) facing junk catcher (2, 2′), and bridge plug (4, 4′) comprises an equalizing channel (71) in a mandrel (7). The equalizing channel (71) extends from a bull nose (41) of bridge plug (4, 4′), and where junk catcher (2, 2′) is provided with a closing sleeve (26, 26′), closing sleeve (26, 26′) is connected to bridge plug (4, 4′) by at least one shear bolt (38, 38′), and closing sleeve (26, 26′) seals at least one equalizing port (73) in mandrel (7) when bridge plug (4, 4′) is set. A method for operating bridge plug (4, 4′) and junk catcher (2, 2′) assembly is also described.

Claims

1. A junk catcher ( 2, 2′), said junk catcher comprising: the junk catcher (2, 2′) being releasable connected to a retrievable bridge plug (4, 4′), the retrievable bridge plug (4, 4′) being connectable to a setting tool (6) for the deployment of the bridge plug (4, 4′) and the junk catcher (2, 2′) in a borehole (9) or a tubular in the borehole (9); the setting tool (6) extends through a fishing neck (12), a catcher tube (14), a flanged section (16), a valve chamber (18), a closable opening (20) and a portion of a setting sleeve (22, 22′) of the junk catcher (2, 2′); the valve chamber (18) comprises a valve (50) arranged to close the closable opening (20) after retrieval of the setting tool (6) from the junk catcher (2, 2′); the junk catcher (2, 2′) being connected to the bridge plug (4, 4′) by at least one shear bolt (27, 38), the bridge plug (4, 4′) comprises a plug fishing neck (32, 32′) facing the junk catcher (2, 2′), and the bridge plug (4, 4′) comprises an equalizing channel (71) in a mandrel (7), the equalizing channel (71) extending from a bull nose (41) of the bridge plug (4, 4′); the junk catcher (2, 2′) being provided with a closing sleeve (26, 26′), connected to the bridge plug (4, 4′) by at least one shear bolt (38, 38′), and the closing sleeve (26, 26′) seals at least one equalizing port (73) in the mandrel (7) when the bridge plug (4, 4′) is set.

2. The junk catcher (2) according to claim 1, wherein the closing sleeve (26) seals an equalizing hole (40) aligned with the equalizing port (73) by enclosing the plug fishing neck (32) from the outside.

3. The junk catcher (2′) according to claim 1, wherein the closing sleeve (26′) is positioned in an annulus (77) between the plug fishing neck (32′) and the mandrel (7), and seals at least one equalizing port (73) in the mandrel (7).

4. The junk catcher (2′) according to claim 3, wherein the setting sleeve (22′) comprises an internal shoulder (250) positioned in an annulus (87) between the setting sleeve (22′) and the plug fishing neck (32′), the shoulder (250) upon axial displacement relative to the plug fishing neck (32′) abuts a collar (8) projecting over the plug fishing neck (32′), and the collar (8) is connected to the closing sleeve (26′).

5. The junk catcher (2′) according to claim 4, wherein the internal shoulder (250) is formed by a carrier sleeve (25), the carrier sleeve (25) is connected to and forming an elongation of the setting sleeve (22′).

6. The junk catcher (2, 2′) according to claim 1, wherein the valve (50) has an actuating device (52).

7. The junk catcher and bridge plug assembly comprising a junk catcher (2, 2′) according to claim 1 and where the bridge plug (4, 4′) is provided with at least one equalizing port (73) closable by a closing sleeve (26, 26′) which is retrievable together with the junk catcher (2, 2′).

8. A method of operation of a junk catcher (2, 2′) according to claim 1, the method includes: connecting the junk catcher (2, 2′) that has a closable opening (20) for a setting tool (6), to a retrievable bridge plug (4, 4′); connecting the setting tool (6) to the bridge plug (4, 4′); positioning the junk catcher (2, 2′) and the bridge plug (4, 4′) downhole; setting the bridge plug (4, 4′); and retrieving the setting tool (6), characterized in that the method further includes: retrieving the junk catcher (2, 2′) together with a closing sleeve (26, 26′) which on retrieval displaces axially along a plug fishing neck (32, 32′) of the bridge plug (4, 4′); and opening at least one equalizing port (73) in a mandrel (7) by the displacement of the closing sleeve (26, 26′) such that an open channel forms from a bull nose (41) and through the bridge plug (4, 4′), such that pressure may equalize under and above the bridge plug (4, 4′) when the junk catcher (2, 2′) is retrieved.

9. A method of operation of a junk catcher (2, 2′) according to claim 8, where the method further comprises to inspect a the junk catcher (2, 2′) for the presence of the closing sleeve (26, 26′) at the surface to confirm that the at least one equalizing port (73) has been opened.

Description

(1) Below, examples of preferred embodiments and methods are explained under reference to the enclosed drawings, where:

(2) FIG. 1 shows a borehole where a bridge plug is set, a longitudinal section of a junk catcher according to a first embodiment of the invention, and a setting tool in its setting position;

(3) FIG. 2 shows the same as in FIG. 1, but after the setting tool has been released from the bridge plug and partly withdrawn from the junk catcher, and where a closable opening of the junk catcher is closed;

(4) FIG. 3 shows the junk catcher during release from the bridge plug;

(5) FIG. 4 shows in a different scale a perspective view of the bridge plug and the partly sectioned junk catcher;

(6) FIG. 5 shows in a different scale a part sectioned view a bridge plug and a junk catcher according to a second embodiment of the invention, and a portion of the bridge plug and the junk catcher at an enlarged scale;

(7) FIG. 6 shows in a different scale a perspective view with a cut away portion the bridge plug and the junk catcher in a setting mode with a portion of a setting tool; and

(8) FIG. 7 shows in a different scale the same as FIG. 6 after setting of the bridge plug and retrieval of the setting tool.

(9) The figures are relatively schematic and only show details and equipment being essential to the understanding of the invention. Further, the figures may be somewhat distorted with respect to the relative dimensions of details and components shown in the figures. The figures may also be somewhat simplified with respect to the shape and richness of detail of such details and components. Hereinafter, equal, equivalent or corresponding details in the figures will be denoted with substantially the same reference numerals.

(10) On the drawings the reference number 1 denotes an apparatus comprising a junk catcher 2 and a retrievable bridge plug 4. A setting tool 6, which at least partly is positioned inside the junk catcher 2, is connected to the plug 4. In FIGS. 1-3, the apparatus 1 is shown inserted into a borehole 9. The borehole 9 may be open or cased or the apparatus 1 may be inserted in a tubular in the borehole 9.

(11) The junk catcher 2 has a housing 10 that, listed from its upper part in its position of use, includes a so called fishing neck 12, a catcher tube 14, a flanged section 16, a valve chamber 18, a closable opening 20 and a setting sleeve 22 that extends towards the bridge plug 4, see FIG. 1. The functions of each of the components making up the housing 10 are explained below. The housing 10 has a through going axial central opening 24.

(12) Inside the setting sleeve 22 an external closing sleeve 26 is positioned and fastened to the setting sleeve 22. The external closing sleeve 26 is fixed to a number of retainers 28, here four, which are axially movable in separate slots 30 in the setting sleeve 22, see also FIG. 4.

(13) The bridge plug 4, which basically is of a commonly known design, such as disclosed in patent document GB2503202/WO2013164343, has a plug fishing neck 32 that extends in the direction towards the junk catcher 2, and an expansion element 34 that is designed to close the borehole 9 when activated. An equalizing channel 71 inside a mandrel 7 which runs through the bridge plug 4 (see FIG. 4) forms a fluid connection between a bull nose 41 at a lower end portion 410 of the bridge plug 4 in its position of use, and a number of equalizing ports 73 in the mandrel 7 above the bridge plug's 4 packer module 46, as shown in FIG. 5. The equalizing ports 73 are aligned with equalizing holes 40 in the plug fishing neck 32. The closing sleeve 26 covers the equalizing holes 40 and thereby the equalizing ports 73 as well. The closing sleeve 26 is connected to the plug fishing neck 32 by at least one shear bolt 38. The bridge plug 4 also includes other features, such as a retrieval mechanism, not shown, that is known to a skilled person and not further discussed.

(14) The setting tool 6, as shown in FIG. 1, extends into the junk catcher 2. A collar 42 on the setting tool 6 abuts the flanged section 16 of the junk catcher housing 10. A tool centre rod 44 is releasably connected to the plug centre rod 32. The setting tool that is of a well known design is equipped with an actuator 46. The actuator 46 is designed to selectively provide a tensional force in the tool centre rod 44.

(15) The setting tool 6 is connected to the surface in the usual way by use of for instance a tube string 48.

(16) When setting the bridge plug 4, the assembly of junk catcher 2, bridge plug 4 and setting tool 6 is positioned in the borehole 9. Thereafter, the actuator 46 is activated, exerting a pulling force via the tool centre rod 44 to the plug fishing neck 32. The pulling force is counteracted by a compressive force between the collar 42 and flange section 16. The compressive force acts on the bridge plug 4 via the valve chamber 18 and the setting sleeve 22.

(17) Said forces move the setting sleeve 22 along the bridge plug 4 while the retainers 28 are moved in their slots 30, bringing the expansion element 34 of the bridge plug 4 to close against the borehole 9.

(18) When the bridge plug 4 is set with the required force, the tool centre rod 44 is released from the plug fishing neck 32 and the setting tool 6 extracted from the junk catcher 2. The situation is shown in FIG. 2 where the setting tool 6 is being withdrawn from the junk catcher 2. The closing sleeve 26 covers the equalizing holes 40 as shown in FIGS. 1 and 2. Necessary sealing elements are not shown.

(19) The removal of the setting tool 6 from the junk catcher 2 allows a valve 50, which is present in the valve chamber 18 and activated by an actuating device 52, here in the form of a spring, to close the closable opening 20.

(20) In this situation, the fishing neck 12, catcher tube 14 and the valve 50 are making up an upwardly open catching room 54 that is designed to collect sand and other debris and prevent them from reaching the bridge plug 4.

(21) When the bridge plug 4 is to be removed, a fishing tool 56 is connected to the fishing neck 12 of the junk catcher 2. The junk catcher 2 is pulled in the direction away from the bridge plug 4 and the retainers 28 are moving to their end positions in their slots 30. Further pulling force moves the junk catcher 2 further relative the bridge plug 4 and shear off the at least one shear bolt 38 and the closing sleeve 26 is displaced along the plug fishing neck 32 and away from the equalizing holes 40. The equalizing channel 71 is then open. Fluid flows through the equalizing channel 71 and equalizes the well pressure under and above the bridge plug 4. The fluid may flow from under the bridge plug 4 to above the bridge plug 4, or vice versa, depending on the pressure difference. The released junk catcher 2 may then be drawn up to the surface. At the surface a visual inspection of the setting sleeve 22 will document the presence of the closing sleeve 26 and thereby confirm that the equalizing channel 71 is open. The pressure equalizing over the bridge plug 4 is ongoing when the junk catcher 2 is being retrieved.

(22) The bridge plug 4 may then be retrieved by use of a conventional, not shown, retrieval tool. The retrieval tool may retrieve the bridge plug 4 without waiting for the pressure to be equalized and thereby time is saved.

(23) FIGS. 5-7 show a second embodiment of the invention. FIG. 5 shows a junk catcher 2′ and a retrievable bridge plug 4′. The junk catcher 2′ comprises many of the same elements as the junk catcher 2 shown in FIGS. 1-4. Same elements are shown with the same reference numeral and these are not further discussed here.

(24) A setting sleeve 22′ is fastened to a carrier sleeve 25. The carrier sleeve 25 forms a stiff elongation of the setting sleeve 22′. The carrier sleeve 25 is fastened to the bridge plug 4 by at least one shear bolt 27, as seen in the detailed drawing in FIG. 5.

(25) The setting sleeve 22′ and the carrier sleeve 25 surround a portion of a plug fishing neck 32′. The function of the carrier sleeve 25 is described below.

(26) The bridge plug 4′ comprises from its end a bull nose 41, an anchor module 43, a packer module 45, a ratchet tube 47 as known in the art, and described in further detail in GB2503202/WO2013164343. The bull nose 41 comprises a plurality of channels 411 which on the inside of the bull nose 41 are in open fluid communication with the equalizing channel 71 in the mandrel 7. The bull nose 41 is at its free end portion provided with a threaded hole 413 to which other equipment may be attached, as known in the art.

(27) The mandrel 7 is provided with at least one equalizing port 73 at the end of the equalizing channel 71 at the opposite end of the bullet nose 41. The equalizing port 73 is positioned at the opposite side of the bridge plug's 4′ anchor module 43, packer module 45 and ratchet tube 47 relative to the bull nose 41. The equalizing channel 71 is at its end closed with a removable plug 75.

(28) During setting of the bridge plug 4′ and the junk catcher 2′ and prior to retrieval of the junk catcher 2′, the equalizing port 73 is closed by an internal closing sleeve 26′ which is positioned in an annulus 77 formed between the mandrel 7 and the plug fishing neck 32′. The closing sleeve's 26′ closing end 261′ is covering the equalizing port 73.

(29) The closing sleeve 26′ is fastened to the bridge plug 4′ by at least one shear bolt 38′. Two shear bolts 38′ are shown in FIG. 5.

(30) The closing sleeve 26′ is at its end opposite the closing end 261′ threadedly fastened to a collar 8. The collar 8 projects over the plug fishing neck 32′ in the direction of the junk catcher 2′. An outer rim 81 of the collar 8 faces the inner surface of the setting sleeve 22′. The carrier sleeve 25 is shown with a wall thickness that is larger than the wall thickness of the setting sleeve 22′. A shoulder 250 is formed by the carrier sleeve 25 at the inside of the setting sleeve 22′ at the joint between the setting sleeve 22′ and the carrier sleeve 25. The setting sleeve 22′ and the plug fishing neck 32′ form an annulus 87 between the shoulder 250 and the collar 8.

(31) When the plug 4′ is to be removed, a fishing tool 56 is connected to the fishing neck 12 of the junk catcher 2′. The junk catcher 2′ is pulled in a direction away from the bridge plug 4′. The shear bolt 27 is sheared off by the pulling force and the junk catcher 2′ with the setting sleeve 22′ and the carrier sleeve 25 move relative to the plug fishing neck 32′. This movement continues until the shoulder 250 of the carrier sleeve 25 abuts the rim 81 of the collar 8. Further pulling force on the junk catcher 2′ is transferred to the collar 8 and the closing sleeve 26′. The shear bolts 38′ are broken and the collar 8 and the closing sleeve 26′ follow the junk catcher 2′ away from the bridge plug 4′ and is retrieved together with the junk catcher 2′. At the surface the closing sleeve 26′ will protrude from the carrier sleeve 25. The protruding closing sleeve 26′ is a visual confirmation that the equalizing ports 73 have been opened.

(32) After the removal of the closing sleeve 26′, fluid is free to flow through the channels 411, through the equalizing channel 71, through the equalizing ports 73, through the annulus 87 and through openings 40′ in the plug fishing neck 32′, or vice versa. The fluid pressure becomes equal under and above the bridge plug 4′. Equalizing of the pressure is ongoing on retrieval of the junk catcher 2′. A retrieval tool for retrieving the bridge plug 4′ can then be lowered into the borehole 9 immediately after retrieving the junk catcher 2′, and the retrieval tool may retrieve the bridge plug 4′ without further waiting for the pressure to equalize. Thereby time is saved.

(33) In a third embodiment (not shown), a bridge plug similar to the bridge plug 4′ is set without a junk catcher. A different closing sleeve is positioned in the annulus 77. On retrieval of the bridge plug, a retrieval tool (not shown) pushes the closing sleeve towards the bull nose 41. An opening in the closing sleeve aligns with the equalizing port 73. Fluid flows through the equalizing channel 71 and equalizes the well pressure under and above the bridge plug.