A FLUID DIVERTER TOOL, SYSTEM AND METHOD OF DIVERTING A FLUID FLOW IN A WELL

Abstract

A fluid diverter tool, system and method of diverting a fluid flow in a in a well, having: a tubular mandrel and a packer element affixed onto an exterior thereof and operable to sealingly engage an inside of a pipe body to divert a flow of a treatment fluid outwards through holes formed in the pipe bod; and a pressure relief device operable to open and relieve pressure from one side to another side of the packer element when exposed to a given pressure differential acting across the pressure relief device from said one side of the packer element, the pressure relief device also adapted to close when exposed to a lower than said given pressure differential acting thereacross from said one side of the packer element.

Claims

1.-32. (canceled)

33. A fluid diverter tool for use in a pipe body in a well, the diverter tool comprising: a tubular mandrel with a longitudinal bore therethrough and having a first end and an opposite second end, said first end operable to allow receipt of a treatment fluid, and said second end operable to allow discharge of the treatment fluid; a packer element affixed to an exterior surface of the tubular mandrel and located between the first and second ends of the mandrel, the packer element having a first side facing the first end of the mandrel and an opposite second side facing the second end of the mandrel, said packer element shaped and operable to sealingly engage an inside of said pipe body to allow a flow of the treatment fluid to be diverted outwards, characterized in that the packer element comprises a pressure relief device adapted and operable, when open, to relieve pressure from the second side to the first side of the packer element; wherein the pressure relief device is adapted to open upon exposure to a first pressure differential acting across the pressure relief device from the second side of the packer element; and wherein the pressure relief device is adapted to close upon exposure to a lower than said first pressure differential acting across the pressure relief device from the second side of the packer element.

34. The fluid diverter tool according to claim 33, wherein the pressure relief device comprises at least one pressure relief valve disposed within at least one corresponding relief channel extending through the packer element between the first and second sides thereof.

35. The fluid diverter tool according to claim 33, wherein the pressure relief device comprises: at least one relief channel extending through the packer element between the first and second sides thereof; and at least one seal body shaped and operable to sealingly engage and close said relief channel when in a closed seal position, said seal body also operable to move between the closed seal position and a first open seal position at the first side of the packer element so as to allow said relief channel to be closed and opened; wherein the seal body is biased towards the closed seal position; and wherein said bias of the seal body is adapted to yield upon exposure to said first pressure differential so as to allow the seal body to move towards the first open seal position at the first side of the packer element and relieve pressure from the second side to the first side of the packer element.

36. The fluid diverter tool according to claim 35, wherein said relief channel comprises an annular relief channel located between the mandrel and the packer element and extending longitudinally within the packer element so as to separate the mandrel from the packer element; wherein support elements extend between the packer element and the mandrel for supporting the packer element on the mandrel; wherein said seal body comprises an annular seal body slidably disposed on the mandrel for allowing longitudinal movement of the annular seal body between the closed seal position and the first open seal position at the first side of the packer element; and wherein the annular seal body is shaped and operable to sealingly engage the annular relief channel when located therein so as to define the closed seal position of the annular seal body.

37. The fluid diverter tool according to claim 36, wherein the annular seal body is affixed to a seal sleeve slidably disposed on the mandrel for allowing said longitudinal movement of the annular seal body between the closed seal position and the first open seal position at the first side of the packer element; and wherein the seal sleeve is biased towards the closed seal position, thereby also biasing the annular seal body towards the closed seal position.

38. The fluid diverter tool according to claim 35, comprising a releasable holding mechanism operable to releasably hold said seal body in an open holding position at the first side of the packer element before operating the diverter tool in said pipe body.

39. The fluid diverter tool according to claim 33, wherein the packer element comprises one of: a radially extending collar adapted and operable to sealingly engage the inside of said pipe body; and an expandable packer adapted and operable to expand radially to sealingly engage the inside of said pipe body.

40. The fluid diverter tool according to claim 39, wherein the radially extending collar is a cup-shaped packer; and wherein the expandable packer is an axially compressible packer adapted and operable to expand radially upon axial compression thereof.

41. The fluid diverter tool according to claim 33, wherein the packer element is rotatably connected to the mandrel to allow rotation of the mandrel relative to the packer element.

42. A system for diverting a fluid flow in a well, the system comprising: at least one pipe body, including an innermost pipe body, disposed in the well; at least one annulus, including an innermost annulus, located between the innermost pipe body and a surrounding borehole wall of the well; and a plurality of holes formed through a wall of said at least one pipe body and dispersed along a longitudinal section of the well to allow communication between the at least one pipe body and the at least one annulus, characterized in that the system also comprises a fluid diverter tool positioned in the innermost pipe body at said longitudinal section of the well; wherein said second end of the mandrel of the diverter tool is operably connected to a treatment tool adapted and operable to discharge said treatment fluid into the innermost pipe body; wherein said packer element of the diverter tool is in sealing engagement with an inside of the innermost pipe body to allow, if possible, a flow of the treatment fluid to be diverted outwards into the at least one annulus via one or more of said holes in the at least one pipe body along the longitudinal section, the packer element defining a first pipe region above said first side of the packer element and a second pipe region below said second side of the packer element; and wherein said pressure relief device of the diverter tool is operable to open and relieve pressure from the second pipe region to the first pipe region upon exposure to a fluid pressure in the second pipe region being sufficient to generate said first pressure differential across the pressure relief device.

43. The system according to claim 42, comprising a tubular work string disposed in the innermost pipe body and having a lower end connected to said first end of the mandrel of the diverter tool for operating the diverter tool and the treatment tool in the innermost pipe body, and for supplying the treatment fluid thereto.

44. The system according to claim 42, wherein the treatment tool comprises at least one of: a jetting tool adapted and operable to discharge jets of treatment fluid directed outwards into the at least one annulus via said one or more holes in the at least one pipe body; and an open-ended pipe section adapted and operable to discharge the treatment fluid directly into the innermost pipe body.

45. The system according to claim 44, wherein the jetting tool includes a check valve adapted and operable to open upon exposure to a predetermined fluid pressure and discharge said jets of treatment fluid.

46. A method of diverting a fluid flow in a well, the well comprising: at least one pipe body, including an innermost pipe body; at least one annulus, including an innermost annulus, located between the innermost pipe body and a surrounding borehole wall of the well; a plurality of holes formed through a wall of said at least one pipe body and dispersed along a longitudinal section of the well to allow communication between the at least one pipe body and the at least one annulus, characterized in that the method comprises the steps of: a) using a fluid diverter tool and operably connecting said second end of the mandrel of the diverter tool to a treatment tool adapted and operable to allow discharge of said treatment fluid; b) positioning the diverter tool and the treatment tool in the innermost pipe body at said longitudinal section of the well; c) sealingly engage said packer element of the diverter tool with an inside of the innermost pipe body so as to define a first pipe region above said first side of the packer element and a second pipe region below said second side of the packer element; d) displacing the treatment fluid through the diverter tool and the treatment tool so as to discharge into the second pipe region of the innermost pipe body and, if possible, allowing said packer element of the diverter tool to divert a flow of the treatment fluid outwards into the at least one annulus via one or more of said holes in the at least one pipe body along the longitudinal section; and e) allowing said pressure relief device of the diverter tool to open and relieve pressure from the second pipe region to the first pipe region of the innermost pipe body upon exposure to a fluid pressure in the second pipe region being sufficient to generate said first pressure differential across the pressure relief device.

47. The method according to claim 46, comprising connecting said first end of the mandrel to a lower end of a tubular work string for operating the diverter tool and the treatment tool in the innermost pipe body, and for supplying the treatment fluid thereto.

48. The method according to claim 46, further comprising moving the diverter tool and the treatment tool along the longitudinal section whilst displacing the treatment fluid in step d.

49. The method according to claim 46, further comprising rotating the treatment tool whilst displacing the treatment fluid in step d.

50. The method according to claim 46, wherein the displacing of treatment fluid in step operates to increase the fluid pressure in the second pipe region sufficiently to generate the first pressure differential and thus open the pressure relief device in step e.

51. The method according to claim 46, wherein step d comprises displacing the treatment fluid into the second pipe region at a location wherein at least the innermost annulus includes a flow-inhibiting blockage zone within the longitudinal section of the well, said blockage zone inhibiting diversion of the flow of treatment fluid outwards into said annulus via one or more of said holes in the at least one pipe body; and wherein the displacing of treatment fluid at the blockage zone operates to increase the fluid pressure in the second pipe region sufficiently to generate the first pressure differential and thus open the pressure relief device in step e.

52. The method according to claim 46, comprising setting the first pressure differential lower than a fluid pressure required in the second pipe region to break down at least one of the packer element and the surrounding borehole wall of the well.

53. The method according to claim 46, wherein the treatment tool comprises a jetting tool adapted and operable to discharge jets of treatment fluid from the jetting tool; and wherein step d comprises directing said jets of treatment fluid outwards into the at least one annulus via one or more of said holes in the at least one pipe body.

54. The method according to claim 46, wherein the treatment fluid is a fluid selected from a group comprising: a washing fluid for cleaning in the at least one annulus; a spacer fluid for conditioning surfaces defining the at least one annulus; and a fluidized plugging material for forming a plug in the at least one annulus and the at least one pipe body along at least the longitudinal section of the well.

55. The method according to claim 46, comprising using the method in an operation for forming a plug in the at least one annulus and the at least one pipe body along at least the longitudinal section of the well; wherein the treatment fluid is a fluidized plugging material; wherein the treatment tool comprises a jetting tool adapted and operable to discharge jets of fluidized plugging material from the jetting tool; and wherein step d comprises directing said jets of fluidized plugging material outwards into the at least one annulus via one or more of said holes in the at least one pipe body so as to facilitate said plugging of the well.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0158] An exemplary embodiment of the invention is described and depicted in the accompanying drawings, where:

[0159] FIGS. 1-8 show a side view of a well to be plugged using a fluid diverter tool, system and method according to the present invention;

[0160] FIGS. 9-17 show a side view, mostly in cross section, of various features and configurations of the fluid diverter tool as used in successive steps of forming a cross-sectional cement plug in the well.

[0161] FIGS. 1-8 show schematic representations of steps and features of the present system and a method, whereas FIGS. 9-17 show further details, tools and equipment associated with the present fluid diverter tool. FIGS. 1-17 and their associated descriptions below are useful for the understanding of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0162] FIG. 1 shows an embodiment of a system and method according to the invention for diverting a fluid flow in a well 2. The system comprises a pipe body 4 (e.g. a casing or similar) disposed in the well 2, and an annulus 6 located between the pipe body 4 and a surrounding borehole wall 8 defined by formation rocks 9. A plurality of perforations 10 are formed through a wall of the pipe body 4 and are dispersed along a longitudinal section L of the well 2 so as to allow communication between the pipe body 4 and the surrounding annulus 6. In this embodiment, the perforations 10 are of relatively small hole size and have been formed using a conventional perforation gun. The annulus 6 contains contaminants 12 to be removed therefrom and an intermediate and flow-inhibiting blockage zone 14 comprising very hard and wear-resistant cement located within the longitudinal section L.

[0163] The system also comprises a fluid diverter tool 16 according to the invention shown positioned at an upper part of the longitudinal section L, and within an ambient fluid 18 in the pipe body 4, before being activated for operation therein. An upper end of the diverter tool 16 is connected to a lower end of a tubular work string 20 disposed in the pipe body 4 and extending to the surface of the well 2 for operating the diverter tool 16 and for pumping down a suitable treatment fluid thereto. A lower end of the diverter tool 16 is operably connected to a first jetting tool 22 for carrying out a cleaning operation in the annulus 6 along the longitudinal section L. The first jetting tool 22 is provided with a plurality of outwardly directed nozzles 24 for discharging jets of a washing fluid 26 when pumped down thereto via the diverter tool 16 and said tubular work string 20. A releasable plug base 28, in the form of a set of adjoining swab cups, is also releasably connected to, and below, the first jetting tool 22.

[0164] Further, the diverter tool 16 comprises a packer element 30, in the form of a single swab cup, in sealing engagement with an inside of the pipe body 4 so as to allow, if possible, a flow of said washing fluid 26 to be diverted outwards into the annulus 6 via one or more of said perforations 10 in the pipe body 4. The swab cup 30 defines a first pipe region 32 located above a first (convex) side 34 of the swab cup 30 and a second pipe region 36 located below a second (concave) side 38 thereof. The swab cup 30 also includes a pressure relief device 40 in an activated state and operable to open and relieve pressure (and fluid flow) from the second pipe region 36 to the first pipe region 32 upon exposure to a fluid pressure in the second pipe region 36 being sufficient to generate a given first pressure differential acting across the pressure relief device 40.

[0165] FIG. 2 shows the first jetting tool 22 in operation after initially having disconnected said releasable plug base 28 from the first jetting tool 22 and positioned it below the lowermost perforations 10 along the longitudinal section L. In this released position, the plug base 28 forms a platform below said longitudinal section L for supporting a plugging material (e.g. cement slurry) to be introduced in the well 2 at a later stage, as discussed below. FIG. 2 also shows the first jetting tool 22 after subsequently being lifted up and positioned at perforations 10 along an upper part of the longitudinal section L, and whilst discharging jets of washing fluid 26 outwards into the annulus 6 via perforations 10 in the pipe body 4. The jetting action dislodges and removes contaminants 12 located in an upper part of the annulus 6. During this cleaning operation, the diverter tool 16 diverts washing fluid 26 (and potential contaminants 12) outwards into the annulus 6 via one or more perforations 10 in vicinity of the swab cup 30. Due to the efficient fluid diversion afforded by the diverter tool 16, it is possible to obtain efficient fluid flow and displacement through said relatively small sized perforations 10, which facilitates use of a conventional (and cheaper) perforation gun for making said perforations 10 in the pipe body 4.

[0166] During the cleaning operation, the tubular work string 20 and the first jetting tool 22 are rotated and moved slowly downwards whilst pumping washing fluid 26 down and out through the first jetting tool 22 (as described above) so as to progressively wash and clean the annulus 6 along the entire longitudinal section L. Rotation is indicated with a curved arrow on the tubular work string 20. As the first jetting tool 22 and the diverter tool 16 move downwards during operation, dislodged contaminants 12 and washing fluid 26 are forced outwards and upwards via the annulus 6 and past the swab cup 30. This contaminant-laden fluid flow then re-enters the pipe body 4 via perforations 10 above the swab cup 30 and flows onwards to the surface of the well 2. The flow direction of washing fluid 26 (and dislodged contaminants 12) is shown with downstream-directed arrows in FIG. 2.

[0167] FIG. 3 shows the swab cup 30 of the diverter tool 16 positioned at said flow-inhibiting blockage zone 14 in the annulus 6. The blockage zone 14 inhibits diversion of the flow of washing fluid 26 outwards into the annulus 6 via one or more of said perforations 10 in vicinity of the swab cup 30. The lack of flow diversion at the blockage zone 14 operates to increase the fluid pressure in the second pipe region 36 (below the swab cup 30) sufficiently to generate said first pressure differential across said pressure relief device 40. This opens the pressure relief device 40 and relieves pressure (and fluid flow) from the second pipe region 36 to the first pipe region 32 of the pipe body 4. The relief direction through the relief device 40 is shown with downstream-directed arrows in FIG. 3.

[0168] FIG. 4 shows the first jetting tool 22 and the diverter tool 16 positioned at the lowermost perforations 10 along said longitudinal section L, and after having completed the downward cleaning operation in the annulus 6. If desirable, the first jetting tool 22 and the diverter tool 16 may then be moved upwards to carry out an upwards washing pass along the longitudinal section L. The first jetting tool 22 and the diverter tool 16 may also be moved downwards and then upwards or, alternatively, upwards and then downward, one or more times (passes) during a cleaning operation.

[0169] Upon engaging said flow-inhibiting blockage zone 14 for each such washing pass and thus increasing the fluid pressure in the second pipe region 36, the pressure relief device 40 will operate to relieve this pressure (and a corresponding fluid flow) when said first pressure differential is reached, as described above.

[0170] Although not shown herein, the first jetting tool 22 and diverter tool 16 may optionally be used in a subsequent operation for conditioning surfaces defining the annulus 6 along the longitudinal section L. As such, the first jetting tool 22 may be positioned at the lowermost perforations 10 along the longitudinal section L. A so-called spacer fluid is then pumped down and out through the first jetting tool 22 so as to discharge into the pipe body 4 as jets of spacer fluid directed further outwards into the annulus 6 via one or more perforations 10 at a lower part of the longitudinal section L. During the conditioning operation, the tubular work string 20 and the first jetting tool 22 are rotated and moved upwards whilst pumping spacer fluid down and out through the first jetting tool 22 (as described above) so as to progressively condition the surfaces of the annulus 6 along the entire longitudinal section L. Upon engaging said flow-inhibiting blockage zone 14 and thus increasing the fluid pressure in the second pipe region 36, the pressure relief device 40 will again operate to relieve the increased fluid pressure, as described above. Similar to that of the cleaning operation, various directions of tool movement may be employed in the conditioning operation, as desirable.

[0171] FIG. 5 shows the fluid diverter tool 16 having its lower end operably connected to a second jetting tool 42 for carrying out a separate and subsequent plugging operation in the annulus 6, and along the longitudinal section L. Similar to the first jetting tool 22, the second jetting tool 42 is provided with several outwardly directed nozzles 44 for discharging jets of a fluidized plugging material 46, in the form of cement slurry, via the diverter tool 16 and said tubular work string 20 when pumped thereto. The second jetting tool 42 also includes a check valve arrangement, both of which are discussed in further detail below. The purpose of the plugging operation is to pump and jet cement slurry 46 into both the pipe body 4 and the previously cleaned (and conditioned) annulus 6 along at least the longitudinal section L so as to form a cross-sectional cement plug 46′ in the well 2 (see FIG. 7). Considering a generally higher fluid density of the cement slurry 46 and a generally higher fluid pressure used during the plugging operation, the diverter tool 16 used in the plugging operation may be scaled and modified somewhat relative to that of the diverter tool used in the preceding cleaning (and optional conditioning) operation. The general principles of the present diverter tool 16 and its embodiments, as disclosed herein, nevertheless apply for all of these operations.

[0172] FIG. 5 also shows the second jetting tool 42 and the diverter tool 16 positioned at the lowermost perforations 10 along said longitudinal section L, and after having initiated the plugging operation. The second jetting tool 42 is discharging jets of cement slurry 46 into the pipe body 4 and further outwards into the annulus 6 via one or more of said perforations 10 in the pipe body 4. The jetting action ensures better access and displacement of cement slurry 46 into various places and voids in the annulus 6. Simultaneously, the swab cup 30 of the diverter tool 16 facilitates the displacement of cement slurry 46 by re-directing and forcing the cement slurry 46 outwards into the annulus 6 via one or more of said perforations 10 during the plugging operation. The swab cup 30 also prevents cement slurry 46 from rising upwards within the pipe body 4 and mixing with said ambient fluid 18 therein (and possible other ambient well fluids) so as to contaminate the cement slurry 46. This ensures minimal mixing of cement slurry 46 with ambient fluids in the well 2 during the plugging operation. The fluid diversion afforded by the swab cup 30 also limits the volume of cement slurry 46 used during the plugging operation so as to save on cement costs. These advantageous effects (minimal mixing, limited fluid volume, reduced fluid costs) contribute to optimize the overall plugging operation. These advantageous effects also apply to any preceding conditioning operation and/or cleaning operation, as described above, and are thus in line with the objects of the invention.

[0173] Further, the tubular work string 20 and the second jetting tool 42 are rotated and moved slowly upwards during the plugging operation whilst pumping cement slurry 46 down and out through the second jetting tool 42 (as described above) so as to progressively fill both the pipe body 4 and the annulus 6 along the entire longitudinal section L. Rotation is indicated with a curved arrow on the tubular work string 20. The pump rate and movement speed upwards are generally attuned relative to one another so as to ensure that the fill rate of cement slurry 46 follows the movement of the swab cup 30 during the plugging operation. Should the fill rate of cement slurry 46 exceed said movement speed so as to place a column of cement slurry 46 on top of the swab cup 30, the column of cement slurry 46 may generate a sufficiently high (second) pressure differential across the pressure relief device 40 for it to open and relieve pressure (and flow of cement slurry 46) from the (upper) first pipe region 32 to the second pipe region 36 below the swab cup 30. This mode of operation and pressure relief is also discussed below in context of FIG. 17.

[0174] FIG. 6 shows the swab cup 30 of the diverter tool 16 positioned at said flow-inhibiting blockage zone 14 in the annulus 6. Also in this case, the lack of flow diversion at the blockage zone 14 operates to increase the fluid pressure in the second pipe region 36 (below the swab cup 30) sufficiently to generate said first pressure differential across said pressure relief device 40. This opens the pressure relief device 40 and relieves pressure (and fluid flow) from the second pipe region 36 to the first pipe region 32 of the pipe body 4, as discussed above. The relief direction through the relief device 40 is shown with downstream-directed arrows in FIG. 6.

[0175] FIG. 7 shows the diverter tool 16 and the second jetting tool 42 positioned at the uppermost perforations 10 along the longitudinal section L, and after having completed the plugging operation. Should the plugging operation be completed some distance above the uppermost perforations 10 (i.e. in any unperforated “blank” pipe section) so as to prevent the cement slurry 46 from flowing outwards, which is not shown herein, the fluid pressure in the second pipe region 36 would again increase sufficiently to open said pressure relief device 40 and thus relieve pressure (and fluid flow) from the second pipe region 36 to the first pipe region 32, as described above.

[0176] FIG. 8 shows the well 2 after having removed the diverter tool 16 and the second jetting tool 42 from the well 2, and after having allowed the cement slurry 46 to harden in the pipe body 4 and in the surrounding annulus 6 so as to form a cross-sectional cement plug 46′ along the entire longitudinal section L of the well 2.

[0177] From the above, it is evident that this particular embodiment of the invention describes use of the diverter tool 16 in two separate runs into the well 2. In the first run, the diverter tool 16 is operably connected to the first jetting tool 22 for carrying out said cleaning (and optional conditioning) operation in the well 2. In the second run, the diverter tool 16 is operably connected to the second jetting tool 42 for carrying out said plugging operation in the well 2.

[0178] In another embodiment not shown herein, the first and second jetting tools 22, 42 may be operably connected, one above the other, for carrying out consecutive and corresponding operations during the same run into the well 2. Various ball-drop (or similar) activation mechanisms, as known in the art, may be used to activate each respective jetting tool 22, 42 for each consecutive operation in the well 2. The second jetting tool 42 for displacing said cement slurry 46 may thus be connected directly below the diverter tool 16, whereas the first jetting tool 22 (or some other suitable washing tool) for displacing said washing fluid 26 may be connected directly below the second jetting tool 42. When running into the pipe body 4 and subsequently activating the lowermost second jetting tool 42 (for said cleaning operation), the pressure relief device 40 of the diverter tool 16 may be kept in an open and inactivate position using, for example, a releasable holding mechanism arranged above said first side 34 of the swab cup 30, as discussed below and shown in FIGS. 9-13. The flow of washing fluid 26 (and removed contaminants 12) may thus flow via both the annulus 6 (as discussed above) and the open pressure relief device 40 during the entire cleaning operation. The subsequent plugging operation is initiated (during the same run into the well 2) by activating both the uppermost first jetting tool 22 and the pressure relief device 40, as discussed below and shown in FIG. 14. The plugging operation then proceeds as discussed above and shown in FIGS. 5-7.

[0179] FIGS. 9-12 show the fluid diverter tool 16 and the second jetting tool 42 as configured in a run-in position for introduction in said pipe body 4 in the well 2. FIG. 12 shows an enlarged version of this tool configuration, whereas FIG. 11 shows a transverse cross section through the diverter tool 16 taken along section line A-A in FIG. 9.

[0180] Further, FIGS. 9-17 show specific features, including internal features, of the fluid diverter tool 16 and the second jetting tool 42 (and said check valve arrangement) connected thereto for carrying out the plugging operation described above. These figures also show various positions of components of the diverter tool 16 and the second jetting tool 42, as applicable to the various functions thereof. Enlarged versions of the various tool configurations are also depicted in FIGS. 13-17.

[0181] The diverter tool 16 comprises a tubular mandrel 48 with a longitudinal bore 50 therethrough and having a first (upper) end 52 connected to said tubular work string 20, and a second (lower) end 54 operably connected to the second jetting tool 42. The swab cup 30 is rotatably affixed to an exterior surface of the mandrel 48 and is located between the first and second ends 52, 54 thereof. Further, the swab cup 30 comprises a cup-shaped packer body 56 formed from a resilient material. An upper side of the packer body 56 defines said first (convex) side 34 of the swab cup 30 and faces the first end 52 of the mandrel 48, whereas a lower side of the packer body 56 defines said second (concave) side 38 of the swab cup 30 and faces the second end 54 of the mandrel 48. The swab cup 30 also includes a tubular support body 58 formed (e.g. machined) or assembled (from individual parts) so as to comprise an outer support ring 58a, an inner support ring 58b and a plurality of support struts 58c extending axially and transversely between the inner and outer support rings 58a, 58b. The support struts 58c are spaced apart circumferentially so as to allow bypass of fluids when required. The packer body 56 is mounted onto the outer support ring 58a and is held in place by an adjoining retainer ring 60. The inner support ring 58b is rotatably mounted onto a low friction bushing 62 (or a suitable bearing) affixed to the exterior surface of the mandrel 48 at (i.e. below) the second side 38 of the swab cup 30. The bushing 62 is made from a suitable low friction material, for example brass or a composite plastics material. This rotary arrangement supports the swab cup 30 on the mandrel 48 and allows relative rotation of the mandrel 48 and the second jetting tool 42 with respect to the swab cup 30 when rotating said work string 20 during operation in the well 2, as indicated with a curved arrow in FIGS. 5 and 6.

[0182] In this embodiment, said pressure relief device 40 of the diverter tool 16 comprises an annular relief channel 64 formed between the mandrel 48 and an inside of the outer support ring 58a of the swab cup 30. The relief channel 64 extends longitudinally between the first and second sides 34, 38 of the swab cup 30 so as to separate the mandrel 48 from the outer support ring 58a and packer body 56 of the swab cup 30. The pressure relief device 40 also comprises an annular seal body 66 shaped and operable to sealingly engage the annular relief channel 64 when located at any position within and along the relief channel 64 so as to define a closed seal position of the annular seal body 66. In this embodiment, the annular seal body 66 seals against said inside of the outer support ring 58a and thus defines an outer extremity of the annular relief channel 64. The annular seal body 66 is made from a resilient material, for example rubber or elastomer material, and is capable of flexing and sealing against said inside of the outer support ring 58a. The annular seal body 66 is affixed to an exterior surface of an end of a seal sleeve 68, which is slidably and sealingly disposed around the mandrel 48 at (i.e. above) the first side 34 of the swab cup 30. The slidable seal sleeve 68 allows longitudinal (axial) movement of the annular seal body 66 between a closed seal position within the annular relief channel 64 and a first open seal position at (i.e. above) the first side 34 of the swab cup 30. This allows the annular relief channel 64 to be closed and opened, as shown in FIGS. 14 and 16 and in FIGS. 9-13, 15 and 17, respectively. The diverter tool 16 also comprises a biasing device 70 in the form of a coil spring disposed around the mandrel 48 above the first side 34 of the swab cup 30. The coil spring 70 is in operable contact with the slidable seal sleeve 68. When activated and operational in the well 2, the coil spring 70 biases the slidable seal sleeve 68 and thus the annular seal body 66 towards its closed seal position within the annular relief channel 66, as shown in FIGS. 14 and 16.

[0183] Said coil spring 70 is also an integral part of a releasable holding mechanism 72 operable to releasably hold the annular seal body 66, and thus the slidable seal sleeve 68 to which it is affixed, in an open holding position at (i.e. above) the first side 34 of the swab cup 30 before operating the diverter tool 16 in the well 2, as shown in FIGS. 9-13. This allows fluids to pass through the annular relief channel 64, as shown with downstream-directed arrows in FIG. 12, and thus facilitates insertion of the diverter tool 16 and said jetting tool 42 in the well 2. The holding mechanism 72 also comprises a recessed section 74 formed in the exterior surface of the slidable seal sleeve 68 and defined between a first ledge 76 and an opposite second ledge 78 thereof. A first detent ring 80 and a second detent ring 82 are slidably disposed on the recessed section 74 so at to be moveable between said first and second ledges 76, 78 thereof. The coil spring 70 is disposed between the detent rings 80, 82 and may thus be expanded or compressed within the confines of the first and second ledges 78, 80. The holding mechanism 72 also includes a housing 84 comprising a housing proper 84a and an adjoining housing sleeve 84b extending towards the swab cup 30 and around the mandrel 48. A first internal ledge 86 defined between the housing proper 84a and the housing sleeve 84b serves to limit the longitudinal movement of the slidable seal sleeve 68, and thus of the annular seal body 66, towards its first open seal position, as shown in FIG. 15. A second internal ledge 84c of the housing sleeve 84b serves to limit longitudinal movement of the first detent ring 80, and thus of the coil spring 70, away from the swab cup 30, as shown in FIGS. 9, 12 and 13. A finger sleeve 88 is also affixed to an exterior surface of the housing sleeve 84b and extends further towards the swab cup 30 so as to enclose the first and second detent rings 80, 82 and their intermediate coil spring 70. A free end of the finger sleeve 88 is provided with a plurality of inwardly protruding fingers 90 serving to limit longitudinal movement of said second detent ring 82, and thus of the coil spring 70, towards the swab cup 30, as shown in FIGS. 9, 12 and 13. When releasably held in said open holding position, the sliding seal sleeve 68 abuts the internal ledge 86 of the housing 84 whilst the first detent ring 80 simultaneously abuts the first ledge 76 of the recessed section 74 and holds the coil spring 70 in a compressed state between the first and second detent rings 80, 82, as shown in FIGS. 9, 12 and 13. Said housing proper 84a is also connected to the first end 52 of the mandrel 48 and is adapted for connection to the lower end of said tubular work string 20.

[0184] Further, the releasable holding mechanism 72 includes a plurality of radial holes 92 formed in the mandrel 48 and spaced apart along its circumference. Each hole 92 is provided with a retaining ball 94 having an outer part extending into a circumferential retaining groove 96 formed in an interior surface of the sliding seal sleeve 68. The retaining groove 96 defines an outer radial position for the retaining balls 94. In this outer position, the retaining balls 94 serve to releasably hold the sliding seal sleeve 68 and its annular seal body 66 in said open holding position. An activation sleeve 98 is positioned within the longitudinal bore 50 of the mandrel 48 and is slidably disposed therein between a first activation position and a second activation position. When in the first activation position, a proximate end 100 of the activation sleeve 98 covers said holes 92 in the mandrel 48 so as to hold the retaining balls 94 in said outer radial position, as shown in FIGS. 9 and 12. When in second activation position, the proximate end 100 of the activation sleeve 98 does not cover said holes 92 and thus allows the retaining balls 94 to move to an inner radial position within the mandrel 48 so as to release the holding mechanism 72.

[0185] In order to facilitate movement from the first to the second activation position, the activation sleeve 98 includes an internal ball seat 102 and a plurality of radial discharge ports 104 formed at an opposite distal end 106 thereof. The radial discharge ports 104 are distributed along the circumference of said distal end 106. The ball seat 102 is adapted to receive an activation ball 108 dropped down from the surface of the well 2 via said tubular work string 20, as shown in FIG. 13. Upon subsequently pumping cement slurry 46 down the tubular work string 20 and thus pressurizing the activation ball 108 and its ball seat 102, the activation sleeve 98 is moved downwards to said second activation position, as shown in FIG. 14. This movement of the activation sleeve 98 to its second activation position uncovers said radial holes 92 in the mandrel 48 and allows the retaining balls 94 to drop into the mandrel 48 and down onto the activation ball 108, which simultaneously releases the slidable seal sleeve 68 disposed on the mandrel 48. The release of the slidable seal sleeve 68 allows the compressed coil spring 70 to rapidly expand and move the slidable seal sleeve 68 and its annular seal body 66 from said open holding position to said closed and biased seal position within the annular relief channel 64, thereby also defining an operational position of the fluid diverter tool 16.

[0186] Movement of the activation sleeve 98 to its second activation position also operates to activate the second jetting tool 42, which is connected to the second (lower) end 54 of the mandrel 48. The second jetting tool 42 is provided with a plurality of outwardly directed nozzles 110 dispersed along a circumference thereof and embedded as nozzle inserts in a wall of the jetting tool 42. The nozzles 110 are connected to corresponding discharge conduits 112 formed through the wall of the jetting tool 42. In this embodiment, the second jetting tool 42 also includes a check valve 114 comprising a coil spring 116 disposed within a housing bore 118 of the jetting tool 42 and around a carrier sleeve 120 slidable arranged within the jetting tool 42, as shown in FIG. 9. The carrier sleeve 120 is connected to the distal end 106 of said activation sleeve 98 (within the mandrel 4) so as to allow the coil spring 116 to bias the activation sleeve 98 in its first activation position and thus cover said radial holes 92 in the mandrel 48, as shown in FIGS. 9-13. In this first activation position, said radial discharge ports 104 in the activation sleeve 98 do not register with the discharge conduits 112 in the jetting tool 42, thereby closing the check valve 114 and preventing jetting of the cement slurry 46 from the nozzles 110 in the jetting tool 42. Upon increasing the cement slurry pressure (above the seated activation ball 108) to a predetermined level, the activation sleeve 98 is moved downward to its second activation position, as shown in FIG. 14, so as to open the check valve 114 and compress the coil spring 116 within said housing bore 118 of the jetting tool 42. In this second activation position, the discharge ports 104 in the activation sleeve 98 do register with the discharge conduits 112 in the jetting tool 42 so as to allow cement slurry 46 to be jetted from the nozzles 110 of the jetting tool 42, thereby also defining an operational position of the second jetting tool 42.

[0187] FIG. 14 shows the fluid diverter tool 16 and the second jetting tool 42 in their respective operational positions for carrying out the plugging operation shown in FIGS. 5-6, and after having released the holding mechanism 72 of the diverter tool 16, as described above. In this operational position, the annular seal body 66 is located in its closed seal position within the annular relief channel 64. The coil spring 70 (in the holding mechanism 72) has also been released and expanded so as to bias the slidable seal sleeve 68 and its annular seal body 66 towards said closed seal position within the annular relief channel 66. When in this expanded position, the protruding fingers 90 of said finger sleeve 88 serve to limit longitudinal movement of the coil spring 70, and thus of the slidable seal sleeve 68, towards the swab cup 30, which also limits the extent of longitudinal movement of the annular seal body 66 within the annular relief channel 64. Simultaneously, the check valve 114 is open so as to allow operation of the second jetting tool 42.

[0188] FIG. 15 shows the swab cup 30 and its pressure relief device 40 as configured in a pressure relief position when exposed, during operation, to said first pressure differential across the pressure relief device 40. The check valve 114 is still open to allow operation of the jetting tool 42. In this embodiment, this relief configuration pertains to the situation shown in FIG. 6, in which the diverter tool 16 is positioned at said flow-inhibiting blockage zone 14 so as to inhibit diversion of cement slurry 46 into said annulus 6. As described above, this flow blockage increases the pressure in the second pipe region 36 sufficiently to generate said first pressure differential across the pressure relief device 40, which in turn is operable to open the pressure relief device 40 and relieve pressure (and fluid flow) from the second pipe region 36 to the first pipe region 32 of the pipe body 4. This pressure differential also serves to force the annular seal body 66 and its slidable seal sleeve 68 away from the swab cup 30 and into a first open seal position at (i.e. above) said first side 34 of the swab cup 30, as shown in FIG. 15. In this embodiment, this first open seal position coincides with said open holding position associated with the releasable holding mechanism 72. The direction of pressure relief is shown with downstream-directed arrows in FIG. 15.

[0189] FIG. 16 shows the swab cup 30 and its pressure relief device 40 as configured in a neutral (inoperative) position after having stopped pumping of cement slurry 46, or after having completed the plugging operation, and thus having lowered the pressure in the cement slurry 46 to below said predetermined level. In such an event, the inherent energy of the compressed coil spring 116 of the check valve 114 overcomes the fluid pressure and forces the activation sleeve 98 back upwards to its first activation position so as to close the check valve 114. By so doing, the check valve 114 prevents so-called U-tubing when a high-density cement slurry 46 is pumped into the well 2, which serves to avoid or reduce any mixing of the cement slurry 46 with ambient fluids in the well 2 so as to contaminate the cement slurry 46. Such a stop in the pumping of cement slurry 46 may occur when “making a connection” to add or remove a tubular element (i.e. a “pipe joint”) in the tubular work string 20 (e.g. jointed drill string) in context of inserting or withdrawing the work string 20 from the well 2. In this neutral position, however, the annular seal body 66 is still in its closed seal position within the annular relief channel 64 of the swab cup 30.

[0190] FIG. 17 shows the swab cup 30 and its pressure relief device 40 as configured in a withdrawal position after having completed the plugging operation (or as configured with a column of cement slurry 46 on top of the swab cup 30 during the plugging operation described above in context of FIG. 5). When withdrawing the diverter tool 16 and second jetting tool 42 from the well 2, the ambient fluid 18 in the pipe body 4 generates a second pressure differential acting on the annular seal body 66 from the first (upper) side 34 of the swab cup 30. The second pressure differential is operable to move the annular seal body 66 longitudinally from its closed seal position within the annular relief channel 64 to a second open position at (i.e. below) the opposite second side 38 of the swab cup 30, which allows the annular relief channel 64 to be opened in the opposite direction. Movement of the annular seal body 66 to this second open position is possible because the bias afforded by said coil spring 70 (of the diverter tool 16), which is connected to the slidable seal sleeve 68 at (i.e. above) the first side of the swab cup 30, also is adapted to yield in the opposite direction upon exposure to said second pressure differential. During this opposite movement, the slidable seal sleeve 68 is moved away from its abutment with the internal ledge 86 of said housing 84 whilst simultaneously compressing the coils spring 70 within the confines of the first and second ledges 78, 80. As shown in FIG. 17, the longitudinal movement of the slidable seal sleeve 68, and thus of the annular seal body 66, towards said second open position is limited by the protruding fingers 90 of the finger sleeve 88 on said housing sleeve 84b. Preferably, said second pressure differential acting from the first side 34 of the swab cup 30 is lower than said first pressure differential acting from the second side 38 of the swab cup 30, which facilitates easy upward movement or withdrawal of the diverter tool 16 from the pipe body 4.

[0191] It is to be understood that the functions and modes of configuration and operation, as disclosed in the above embodiment and figures of the present fluid diverter tool, system and method, also may be used with any other embodiments disclosed herein, and in any combination thereof, as defined within the scope of the subsequent claims.