WO2012138231A1 - Cutting tool for use in fluid-filled cavities and use of the tool - Google Patents

Cutting tool for use in fluid-filled cavities and use of the tool Download PDF

Info

Publication number
WO2012138231A1
WO2012138231A1 PCT/NO2012/050057 NO2012050057W WO2012138231A1 WO 2012138231 A1 WO2012138231 A1 WO 2012138231A1 NO 2012050057 W NO2012050057 W NO 2012050057W WO 2012138231 A1 WO2012138231 A1 WO 2012138231A1
Authority
WO
WIPO (PCT)
Prior art keywords
cutting tool
piston
fluid
elongated body
elongated
Prior art date
Application number
PCT/NO2012/050057
Other languages
French (fr)
Inventor
Karl Berner Garvik
Original Assignee
Deepwell As
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 Deepwell As filed Critical Deepwell As
Priority to EP12768317.5A priority Critical patent/EP2694774A4/en
Publication of WO2012138231A1 publication Critical patent/WO2012138231A1/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
    • E21B29/04—Cutting of wire lines or the like

Definitions

  • the invention relates to a cutting tool for cutting elongated bodies in a fluid-filled cavity. More particularly, the invention relates to a cutting tool for cutting wires or long rods which are used in the petroleum industry to carry out operations in boreholes or petroleum wells.
  • the steel cable or rod may get stuck in the well. This may happen, for example, if the borehole collapses, locking through a pressure difference between the borehole and formation, so-called “differential sticking” or by material, such as sand for example, caving in on or around the cable. In such situations it is necessary to free the cable by cutting it as close as possible to where it is stuck.
  • a cutting tool which is moved down along the cable.
  • a tool is known by the trade name of Kinley Sandline Cutter. This is a bipartite tool. One part includes a knife which is forced into the cable by the discharge of an explosive charge. This part is slipped over the cable and moved by means of gravity into the well.
  • the explosive charge is discharged when the second part, in the form of a weight, follows the first part and hits it.
  • Another tool is known by the trade name of Flopetrol - Rotary Wireline Cutter.
  • This cutting tool is provided, in its lower end portion, with a crescent- shaped, flat, rotatable knife piece resting on a circularly shaped recess.
  • the knife piece is rotatable around a horizontal axis. In its position of application, the knife piece is provided with a vertical slot extending radially from one edge of the knife piece in towards and past the centre of the knife piece.
  • the slot is arranged to be slipped over the cable and in such a way that the knife piece forms two fingers, one finger on either side of the cable.
  • the cutting edge of the knife piece is formed at the bottom of the slot between the fingers.
  • the edge of the knife piece facing away from the slot forms a cam and the slot is formed in such a way that the cam projects upwards when the cutting tool is moved down along the cable.
  • the cutting tool is slipped over the cable and dropped down along the cable. When the cutting tool hits the barrier holding the cable fixed, the upper portion of the cutting tool will strike via an impact piece against the cam of the knife piece, turning it around so that the cutting edge is forced into and through the cable. This cutting tool requires great speed to achieve a momentum large enough to cut the cable.
  • the patent document US 6,763,753 / US 6,805,197 discloses a combination tool for retrieving a stuck, wireline tool in a well and for cutting the cable attached to the wireline tool.
  • the combination tool is mounted at the lower end of a tubular work string, for example coiled tubing.
  • the combination tool includes a cutting de- vice.
  • the cutting device includes one axially movable piston which is in fluid communication at both end portions with an elongated inner space in the tubular work string.
  • the axially movable piston abuts against an axially movable wedge.
  • the axially movable wedge abuts against a radially movable wedge which is provided with a cutting blade directed inwards.
  • the radially movable wedge is fixed to the housing of the combination tool by a shear screw.
  • the cable which is attached to the stuck wireline tool extends axially through the centre of the combination tool.
  • the cable also extends axially through the axially movable piston.
  • the pressure of the fluid within the tubular work string may be kept higher than the pressure of the fluid present in the annulus formed between the work string and the wall of the borehole.
  • the wall of the borehole may be formed by production tubing or casing.
  • the pressure against the axially movable piston will result in tensile stress on the shear screw.
  • this tensile stress is sufficient to break the shear screw, the radially movable wedge with the cutting blade moves against the cable, and the cable is cut.
  • the operation of this tool is independent of the fluid pressure in the annulus .
  • One known drawback of some of the prior art cutting tools is that they are less suitable when the well has been drilled with a deviation, especially when the deviation is larger than 60°. There is uncertainty about whether the cutting tool will reach the desired depth, whether the triggering weight will reach the tool or whether the speed will be great enough to trigger the tool .
  • an elongated body is meant, in what follows, a steel wire, a steel cable, a metal rod or a carbon-fibre rod / carbon- fibre cable, for example.
  • the steel wire may be provided with one or more electrical conductors
  • the carbon- fibre rod may be provided with one or more electrical conductors and/or fibre optics.
  • a borehole By an elongated cavity is meant, in what follows, a borehole, a borehole provided with one or more casings, one casing may be on the outside of the other, or a drilling pipe.
  • the borehole may be a well, such as an exploration well, a production well or an injection well, for example.
  • the well may be used for petroleum recovery, energy production or production of drinking water or water for irrigation purposes.
  • a fluid By a fluid is meant, in what follows, for example liquids like water, seawater, brine, completion fluid, drilling fluid, drilling mud and oil, or gas, and mixtures of gas and liquids .
  • the invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.
  • the invention relates to a cutting tool arranged to cut, completely or partially, an elongated body, the body extending axially in a fluid-filled, elongated cavity surrounding the cutting tool; the cutting tool being provided with a cutter arranged to cut the elongated body completely or partially; the cutter including at least one knife with a cutting edge, the knife being arranged to force the cutting edge completely or partially through the elongated body; the cutting tool including at least one axially movable piston with a first piston surface facing away from the cutter and with a second piston surface facing the cutter; the second piston surface being in fluid communication with the fluid in the elongated cavity, and the area of the first piston surface being larger than the area of the second piston surface; and a wedge-shaped portion provided with a sloping surface being arranged to move the knife towards the elongated body when the wedge-shaped portion is moved axially along the cutting tool, and the first piston surface being in fluid communication with the fluid in the elongated cavity.
  • the area of the first piston surface is meant the sum of the effective, operative area of one or more surfaces that are perpendicular to the longitudinal axis of the cutting tool and that are facing away from the cutter.
  • the area of the second piston surface is meant the effective, operative area of one or more surfaces that are perpendicular to the longitudinal axis of the cutting tool and that are facing the cutter.
  • the projected area of the surface on a perpendicular surface will constitute the effective, operative area.
  • the operative area is the area which is in contact with the fluid in the elongated cavity.
  • the cutter may further include at least one axially movable wedge provided with a sloping surface arranged to move the knife against the elongated body when the wedge is moved axially along the cutting tool, the piston pushing against the wedge as the piston is being moved axially against the cutter .
  • the piston of the cutting tool may be constituted by several cooperating pistons.
  • the pistons may be fixedly connected.
  • the pistons may have piston surfaces following one behind the other in the axial direction.
  • the cutting tool may include an axial guide forming an axial channel .
  • An annular space at the first piston surface may be in fluid communication with the axial channel .
  • the cutting tool may include an axial guide forming a through-going channel .
  • the axial guide with the through-going channel may be arranged to accommodate the elongated body.
  • An annular space at the first piston surface is in fluid communication with the through-going channel .
  • the piston may be held fixed by at least one shear body.
  • the cutter may include at least two knives .
  • the cutter may include at least two wedges.
  • the cutting tool may be provided with an activatable clamping device arranged to hold the cutting tool fixed to the elongated body in a portion above the knife after activation of the knife.
  • the clamping device may hold the cutting tool fixed to a portion of the cut elongated body which is positioned above a cutting point.
  • the at least one knife may cut the elongated body completely or partially with a cut forming an angle of between 15° and 165° to the longitudinal axis of the elongated body.
  • the cut may form an angle of between 30° and 150° to the longitudinal axis of the elongated body.
  • the cut may form an angle of between 45° and 135° to the longitudinal axis of the elongated body.
  • the cut may form an angle of between 60° and 120° to the longitudinal axis of the elongated body.
  • the cut may form an angle of between 75° and 105° to the longitudinal axis of the elongated body.
  • the cut may form an angle of between 80° and 100° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 85° and 95° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form a radial cut of 90° to the longitudinal axis of the elongated body.
  • the invention may also include equipment for operations in a fluid-filled, elongated cavity including an elongated body extending axially in the elongated cavity, the elongated body being provided with the movable cutting tool described above.
  • the invention relates to a method of cutting an elongated body in a fluid-filled elongated cavity, the method including:
  • the method may further include adjusting the pressure of the elongated cavity from the outside of the elongated cavity. This may be carried out with pumps of a kind known per se, which are placed at the surface where the elongated cavity has its mouth.
  • Figure 1 shows a view of the cutting tool in accordance with the invention positioned in a well, the pipe wall of the well being shown in section;
  • Figures 2A-C show on the same scale, in A, a view of the cutting tool in accordance the invention; in B, a cutaway view of the cutting tool before activation and, in C, a cut-away view after activation;
  • Figure 3 shows, on the same scale, but in a greater degree of detail, the same as figure 2B;
  • Figure 4 shows, on a larger scale, the upper half of the
  • Figure 5 shows, on the same scale as figure 4, the lower
  • Figure 6 shows a cut-away view on the same scale as figure
  • Figure 7 shows, by and large, the same as figure 6, the tool after activation.
  • the reference numeral 1 indicates a cutting tool in accordance with the invention.
  • the cutting tool 1 includes an outer cylinder-shaped housing 2.
  • the housing 2 In its, in the position of application, upper end portion 21, the housing 2 is provided with an upper end piece 25 and, in its lower end portion 23, the housing 2 is provided with a lower end piece 27.
  • the inner shell surface 20 of the housing 2 In the upper end portion 21 and the lower end portion 23, the inner shell surface 20 of the housing 2 is provided with a threaded portion 22.
  • the upper end piece 25 and the lower end piece 27 are provided with an outer threaded portion 24, so that the upper end piece 25 and the lower end piece 27 may be releasably attached to the housing 2 with a screw connection.
  • the end piece 25 and the end piece 27 are provided with an axial through-going bore 29 which is arranged to accommodate a wire, a cable or a rod 8, as shown in figure 1, and over which the cutting tool 1 may be slipped.
  • the upper end piece 25 is provided with a sealing element 252 bearing seal- ingly against the inner shell surface 20.
  • the bore 29 of the upper end piece 25 is provided with a threaded portion 28.
  • the upper end piece 25 is further provided with a radial channel 90 extending from the bore 29 to a circular, circumferential recess 92 in the upper end piece 25 and forming an annular space 94.
  • the upper end piece 25 is provided with a neck 6, so that the cutting tool 1 may be fished up by a fishing tool of a known kind .
  • the cutting tool 1 is movable along the elongated body 8.
  • the cutting tool 1 is lowered along the elongated body 8 in an elongated fluid-filled cavity 70 which is formed by a pipe 7.
  • the pipe 7 may be constituted by production tubing or casing.
  • the guide 3 includes three substantially like guide elements, termed, in what follows, an upper guide element 30, a middle guide element 31 and a lower guide element 32.
  • the guide 3 also includes a guide sleeve 33.
  • the upper guide element 30 is discussed. It is understood that the discussion correspondingly applies to the guide elements 31 and 32 as well and only differing features are discussed for the guide elements 31, 32.
  • the guide element 30 includes a tubular axial stem 34 and, in its lower portion, a radial end wall 35. The stem 34 extends from the end wall 35 towards the upper end piece 25.
  • the stem 34 is provided with an externally threaded portion 36.
  • the guide elements 30, 31, 32 are provided with an axial through-going channel 39 extending from the upper end portion of the stem 34 through the end wall 35.
  • the channel 39 is provided with a threaded portion 37.
  • the end wall 35 is provided with a sealing element 352 bearing sealingly against a piston 4 which will be discussed in what follows.
  • the stem 34 is provided with a radial bore 38.
  • the end wall 35 is provided with a radial channel 90' extending from the axial channel 39 to a circular, circumferential recess 92' in the end wall 35 and forming an annular space 94 ' .
  • the guide sleeve 33 is formed as the stem 34.
  • the guide sleeve 33 is provided with an internally threaded portion 37'.
  • the upper guide element 30 is releasably screwed to the upper end piece 25 with the screw connection formed by the threaded portions 28 and 36.
  • the threaded portions 28 and 36 are screwed together in such a way that the bore 38 coincides with the channel 90 and a continuous channel is formed from the channel 39 to the annular space 94, 94 ' .
  • the middle guide element 31 is releasably screwed to the upper guide element 30 with the screw connection formed by the threaded portions 36 and 37.
  • the threaded portions 36 and 37 are screwed together in such a way that the bore 38 coincides with the channel 90'.
  • the lower guide element 32 is releasably screwed to the middle guide element 31 and, correspondingly, the guide sleeve 33 is releasably screwed to the lower guide element 32.
  • the cutting device 1 is provided with an internal piston 4 formed by an upper piston 40, two middle pistons 41, 41' and a lower piston 42.
  • the two middle pistons 41, 41' are of substantially like designs.
  • Features which are common to the pistons 40, 41, 41', 42 have the same reference numerals.
  • the piston 4 is provided with a plurality of first piston surfaces 43 extending radially from the guide 3 to an inner shell surface 444 on the side wall 44 of the piston 4.
  • the piston 4 is provided with a central, axial, through-going bore 45.
  • the piston 4 is circumferentially provided with a sealing element 402 bearing sealingly against the shell surface 20, and with a sealing element 404 in the bore 45.
  • the sealing element 404 bears sealingly against the guide 3.
  • the side wall 44 In its upper end portion, the side wall 44 is externally stepped and provided with threads 46 in the outer shell surface 442 of the piston 4. In its lower end portion, the side wall 44 is internally stepped and provided with threads 47 in the inner shell surface 444 of the piston 4. In its outer, upper stepped portion, the side wall 44 is circumferentially provided with a sealing element 412 bearing sealingly against the lower, inner stepped portion of the side wall 44 of the piston 4 above.
  • the upper piston 40 differs from the piston 41, 41' by the side wall 44 of the piston 40 only being formed by a portion 44' projecting downwards.
  • the first piston surface 43' thus extends radially from the guide 3 to the inner shell surface 20.
  • the lower piston 42 differs from the piston 41, 41' by the downward-projecting portion 44" of the side wall 44 having been given a different form.
  • the side wall 44" is circumfer- entially provided with a circular recess 48. After the cutting tool 1 has been assembled, the recess 48 will be flush with a radial, threaded shear-body bore 12 in the housing 2.
  • the shear-body bore 12 and the recess 48 are arranged to accommodate a threaded shear body 14.
  • the side wall 44" forms an abutment surface 49.
  • the abutment surface 49 also constitutes a portion of the second piston surface 490 of the piston 4.
  • the second piston surface 490 is additionally constituted by the surface 492 between the guide sleeve 33 and the inner shell surface 446 of the downward- projecting side wall 44" of the lower piston 42, as shown in figure 5.
  • the pistons 40, 41, 41', 42 are releasably screwed together at the threaded connections 46, 47 so that they form one continuous piston 4.
  • the piston 4 can be moved axially within the housing 2 along the guide 3.
  • the cutting tool 1 is provided with a cutter 5.
  • the cutter 5 includes a cylinder-shaped knife holder 55 holding two knives 51, 51' and holding two wedges 53, 53'.
  • the knife holder 55 forms an internal axial channel 59.
  • the two wedges 53, 53' are provided with sloping surfaces 54, 54' facing inwards and are axially movable along the knife holder 55 in an axial slot 552 formed in the outer shell surface 550 of the knife holder 55.
  • the knives 51, 51' are arranged to be moved radially in towards the centre axis of the cutting tool 1.
  • the knives 51, 51' are formed with a crescent-shaped cutting edge (not shown) facing inwards towards the centre axis of the cutting tool 1.
  • the knives 51, 51' are adapted with a narrow fit to a slot 56 in the knife holder 55 and are held in place in the slot 56 by friction.
  • the knives 51, 51' are of the guillotine type, so that the cutting edges pass each other when the knives 51, 51' are moved radially.
  • the bores 29 in the upper and lower end pieces 25, 27, the channel 39 of the guide 3 and the channel 59 of the knife holder 55 form a continuous, axial channel through the cutting tool 1.
  • the cutting tool 1 is slipped over the wire 8.
  • the cutting tool will glide along the wire 8 and down into the cavity 70.
  • the cutting tool 1 will be surrounded on its outside by the fluid standing in the cavity 70, for example drilling fluid of a kind known per se. The fluid will also surround the wire 8 in the channel 29, 39, 59 of the cutting tool 1.
  • the static pressure of the fluid increases down the cavity 70. Fluid will enter the cutting tool 1 through the bore 29 and further through the bores 38 and the cannels 90, filling the annular spaces 94, 94' completely or partially.
  • the cutting tool 1 is not fluid-tight in its lower portion 23, so that the free, upper end portions of the wedges 53, 53', the knife holder 55 and the lower portion of the guide sleeve 33 will be surrounded by fluid.
  • the fluid in the annular space 94 will exert a pressure on the first piston surface 43 1 of the upper piston 40. This will be balanced by the pressure against the piston 4 from the fluid in the lower portion 23 of the cutting tool 1.
  • the pressure in the annular spaces 94' will drive the piston 4 axially against the shear bodies 14.
  • the shear bodies 14 prevent the piston 4 from moving axially relative to the housing 2.
  • the number of shear bodies 14 may be varied and the breaking strength of the shear bodies 14 may be varied.
  • the shear bodies 14 are cut and the piston 4 moves axially towards the lower end portion 23 of the cutting tool 1.
  • the abutment surface 49 of the lower piston 42 forces the wedges 53, 53' downwards.
  • the sloping surfaces 54, 54' of the wedges 53, 53' force the knives 51, 51' radially inwards against the wire 8, and further into the wire 8 until this is cut, see figure 2C. Thereby it is achieved that the wire 8 is cut at a desired depth in the cavity 70.
  • the cutting tool 1 may further be provided with a feeder cable (not shown) which may be attached to the upper end piece 25.
  • the feeder cable is paid out in a controlled manner, so that the cutting tool 1 is lowered in a controlled manner into the cavity 70.
  • the cutting tool 1 is hoisted up again by means of the feeder cable .
  • the hydrostatic pressure in a cavity 70 may be increased by means of pum s. Thereby the desired cutting depth may also be adjusted by means of the pressure in the cavity 70. If the cutting tool 1 should not reach the intended depth, or the pressure is too low for the shear bodies 14 to break, the cutting tool 1 is activated by increasing the pressure in the cavity 70. If the cutting tool 1 has not reached the intended depth when the cutting tool is activated, the wire 8 will be cut higher up in the cavity 70 and at a distance from the portion in which it is stuck. The major part of the wire 8 may still be freed.
  • the cutting tool 1 is shown in an alternative embodiment in the figures 6 and 7. In these figures, the cutting tool 1 is shown more schematically and only the parts of the cutting tool 1 that are necessary for the understanding of the operation of the tool 1 are discussed. Parts having the same function have been given the same reference numerals as in the figures 1 to 5, but are not necessarily mentioned.
  • the cutting tool 1 On the exterior of the housing 2, the cutting tool 1 is provided with holders 81 for the elongated body 8. The cutting tool 1 is movably connected to the elongated body 8 by means of the holders 81. The cutting tool 1 is lowered along the elongated body 8 in an elongated fluid-filled cavity 70 which is formed by a pipe 7.
  • the pipe 7 may be constituted by production tubing or casing.
  • the end piece 25 is provided with an axial through-going bore 29.
  • a guide 3 extends axially.
  • the guide 3 includes at least one radial end wall 35. In the figures three radial end walls 35 are shown.
  • the guide 3 is provided with an axial, through-going channel 39 extending from the end piece 25, through the end wall 35 to below the lower end wall 35.
  • the channel 39 is in fluid communication with the elongated cavity 70 through the bore 29.
  • the guide 3 is provided with radial, through-going bores 38 which are positioned just below the end walls 35.
  • the guide 3 is further provided with a radial, through-going upper bore 38' just below the upper end portion 21 of the housing 2.
  • the upper bore 38' discharges into an annular space 94 which is formed between the outer surface of the guide 3 and the inner shell surface 20 of the housing 2.
  • the other bores 38 discharge into the annular space 94 1 which is formed between the outer surface of the guide 3 and the inner shell surface 444 of the piston 4.
  • the piston 4 is constituted by an upper piston 40, two middle pistons 41, 41' and a lower piston 42.
  • the piston 4 is provided with a plurality of first piston surfaces 43 extending radially from the guide 3 to an inner shell surface 444 on the side wall 44 of the piston 4.
  • the piston 4 is provided with a central, axial, through-going bore 45.
  • the piston 4 is circumferentially provided with a sealing element 402 which bears sealingly against the shell surface 20, and with a sealing element 404 in the bore 45.
  • the sealing element 404 bears sealingly against the guide 3.
  • the upper piston 40 differs from the piston 41, 41' by the first piston surface 43 ' extending from the guide 3 to the inner shell surface 20.
  • the side wall 44 is circumferentially provided with a circular recess 48.
  • the recess 48 will be flush with a radial, threaded shear- body bore 12 in the housing 2.
  • the shear-body bore 12 and the recess 48 are arranged to accommodate a threaded shear body 14.
  • the piston 4 forms a second piston surface 490.
  • the piston 4 further forms a wedge 53 which is provided with a sloping surface 54 facing inwards, sloping outwards and downwards from the centre of the cutting tool 1.
  • the sloping surface 54 forms a portion of the second piston surface 490.
  • the cutting tool 1 is provided with a cutter 5.
  • the cutter 5 includes a knife 51.
  • the knife 51 is provided with a sloping surface 58 facing outwards, sloping outwards and downwards from the centre of the cutting tool 1.
  • the housing 2 is provided with a through-going opening 26 for the cutting edge 51' of the knife 51.
  • the cutting tool 1 Whenever it is necessary to cut the wire or rod 8 extending down into the elongated, fluid-filled cavity 70, the cutting tool 1 is attached, movably, to the wire 8 with the holder 81. By its own weight, possibly also by weights (not shown) that may be slipped over the wire 8 on the top side of the cutting tool 1, the cutting tool 1 will glide along the wire 8 and down into the cavity 70. In the cavity 70, the cutting tool 1 will be surrounded on its outside by the fluid standing in the cavity 70.
  • the static pressure of the fluid increases down the cavity 70. Fluid will enter the cutting tool 1 through the bore 29, the channel 39 and the bores 38, filling the annular spaces 94, 94' completely or partially.
  • the cutting tool 1 is not fluid-tight in its lower portion 23, so that the second piston surface 490 will be in fluid communication with the cavity 70 through the opening 26.
  • the fluid in the annular space 94 will exert a pressure on the first piston surface 43 ' of the upper piston 40. This will be balanced by the pressure against the second piston surface 490 in the lower portion 23 of the cutting tool 1.
  • the pressure in the annular spaces 94' will force the piston 4 axially against the shear bodies 14 because of the area of the first piston surface 43, 43' being larger than the second piston surface 490.
  • the shear bodies 14 prevent the piston 4 from moving axially relative to the housing 2.
  • the number of shear bodies 14 may be varied and the breaking strength of the shear bodies 14 may be varied.
  • the pressure of the fluid against the piston 4 exceeds the overall breaking strength of the shear bodies 14, the shear bodies 14 are cut and the piston 4 moves axially towards the lower end portion 23 of the cutting tool 1.
  • the wedge 53 of the piston 4 with the sloping surface 54 will force the knife 51 outwards against the wire 8 and further into the wire 8 until this is cut, or possibly it is nearly cut through and is divided by a remaining portion being torn.
  • the cutting tool 1 may be provided with a time-controlled actuator and/or valve 60, possibly with an actuator 60 which can be activated from the surface, as shown in figure 7.
  • the actuator 60 operates fluid-tight valves for the bore 29. When the cutting tool 1 is lowered, there will be no fluid entering the annular spaces 94 , 94 1 . After the cutting tool 1 has been positioned and at a desired time, the actuator opens the valves so that fluid will enter the annular spaces 94, 94' and the cutting tool 1 is activated to cut the wire 8.
  • the cutting tool 1 may be provided with a clamping member 83 which, after the activation of the cutting tool 1, holds the cutting tool 1 fixed to a portion of the cut wire 8 above the cutting point formed by the knife 51. Thereby the cutting tool 1 can be hoisted up together with the cut wire 8 in the cavity 70.
  • a radially movable clamping member 83 is shown schematically in figure 7.
  • the clamping member 83 is accommodated in a slot 85 in the outer shell surface 442 of the piston 4.
  • the inclined wall 87 of the slot 85 abuts against the sloping surface 89 of the clamping member 83, and the clamping member 83 will be moved radially outwards when the piston 4 is moved axially downwards towards the cutter 5.
  • the wire 8 will be clamped between the holder 81 and the clamping member 83.
  • annular spaces 94, 94' may be in fluid communication with the cavity 70 through openings in the wall of the housing 2. In this embodiment, there is no through-going bore 29 and no channel
  • the end walls 35 may have a cross section which is adapted to the inner diameter of the housing 2.
  • the guide 3 may be replaced by an axial piston rod connecting the pistons

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Shearing Machines (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)
  • Lubricants (AREA)

Abstract

A cutting tool (1) arranged to cut an elongated body (8), the body (8) extending axially in a fluid-filled, elongated cavity (70) surrounding the cutting tool (1); the cutting tool (1) being provided with a cutter (5) which is arranged to cut the elongated body (8) completely or partially; the cutter (5) including at least one knife (51, 51') with a cutting edge (52), the knife (51, 51') being arranged to force the cutting edge (52) completely or partially through the elongated body (8); the cutting tool (1) including at least one axially movable piston (4) with a first piston surface (43, 43') facing away from the cutter (5) and with a second piston surface (490) facing the cutter (5); the second piston surface (490) being in fluid communication with the fluid in the elongated cavity (70), and the area of the first piston surface (43, 43') being larger than the area of the second piston surface (490); and a wedge-shaped portion provided with a sloping surface (54, 54') being arranged to move the knife (51, 51') against the elongated body (8) when the wedge-shaped portion is being moved axially along the cutting tool (1), and the first piston surface (43, 43') being in fluid communication with the fluid in the elongated cavity (70). A use of the cutting tool (1) is also discussed.

Description

CUTTING TOOL FOR USE IN FLUID-FILLED CAVITIES AND USE OF THE TOOL
The invention relates to a cutting tool for cutting elongated bodies in a fluid-filled cavity. More particularly, the invention relates to a cutting tool for cutting wires or long rods which are used in the petroleum industry to carry out operations in boreholes or petroleum wells.
Within the petroleum industry, it is known to carry out so- called downhole operations by means of equipment or tools which are lowered by means of gravity into the well, hanging on a steel cable. Within the art, the cable is referred to as a wireline or a slickline. It is also known that the equipment may be attached to a carbon-fibre rod.
The steel cable or rod may get stuck in the well. This may happen, for example, if the borehole collapses, locking through a pressure difference between the borehole and formation, so-called "differential sticking" or by material, such as sand for example, caving in on or around the cable. In such situations it is necessary to free the cable by cutting it as close as possible to where it is stuck. For this purpose, it is known within the art to use a cutting tool which is moved down along the cable. A tool is known by the trade name of Kinley Sandline Cutter. This is a bipartite tool. One part includes a knife which is forced into the cable by the discharge of an explosive charge. This part is slipped over the cable and moved by means of gravity into the well. The explosive charge is discharged when the second part, in the form of a weight, follows the first part and hits it. Within the industry, there are restrictions on the forwarding, storage and use of explosives. Another tool is known by the trade name of Flopetrol - Rotary Wireline Cutter. This cutting tool is provided, in its lower end portion, with a crescent- shaped, flat, rotatable knife piece resting on a circularly shaped recess. The knife piece is rotatable around a horizontal axis. In its position of application, the knife piece is provided with a vertical slot extending radially from one edge of the knife piece in towards and past the centre of the knife piece. The slot is arranged to be slipped over the cable and in such a way that the knife piece forms two fingers, one finger on either side of the cable. The cutting edge of the knife piece is formed at the bottom of the slot between the fingers. The edge of the knife piece facing away from the slot forms a cam and the slot is formed in such a way that the cam projects upwards when the cutting tool is moved down along the cable. The cutting tool is slipped over the cable and dropped down along the cable. When the cutting tool hits the barrier holding the cable fixed, the upper portion of the cutting tool will strike via an impact piece against the cam of the knife piece, turning it around so that the cutting edge is forced into and through the cable. This cutting tool requires great speed to achieve a momentum large enough to cut the cable.
The patent document US 6,763,753 / US 6,805,197 discloses a combination tool for retrieving a stuck, wireline tool in a well and for cutting the cable attached to the wireline tool. The combination tool is mounted at the lower end of a tubular work string, for example coiled tubing. Apart from a lower gripping device, the combination tool includes a cutting de- vice. The cutting device includes one axially movable piston which is in fluid communication at both end portions with an elongated inner space in the tubular work string. At its lower end portion, the axially movable piston abuts against an axially movable wedge. The axially movable wedge abuts against a radially movable wedge which is provided with a cutting blade directed inwards. The radially movable wedge is fixed to the housing of the combination tool by a shear screw. The cable which is attached to the stuck wireline tool extends axially through the centre of the combination tool. Thus, the cable also extends axially through the axially movable piston. The pressure of the fluid within the tubular work string may be kept higher than the pressure of the fluid present in the annulus formed between the work string and the wall of the borehole. The wall of the borehole may be formed by production tubing or casing. At a certain pressure in the fluid within the work string, the pressure against the axially movable piston will result in tensile stress on the shear screw. When this tensile stress is sufficient to break the shear screw, the radially movable wedge with the cutting blade moves against the cable, and the cable is cut. The operation of this tool is independent of the fluid pressure in the annulus .
One known drawback of some of the prior art cutting tools is that they are less suitable when the well has been drilled with a deviation, especially when the deviation is larger than 60°. There is uncertainty about whether the cutting tool will reach the desired depth, whether the triggering weight will reach the tool or whether the speed will be great enough to trigger the tool .
By an elongated body is meant, in what follows, a steel wire, a steel cable, a metal rod or a carbon-fibre rod / carbon- fibre cable, for example. The steel wire may be provided with one or more electrical conductors, and the carbon- fibre rod may be provided with one or more electrical conductors and/or fibre optics.
By an elongated cavity is meant, in what follows, a borehole, a borehole provided with one or more casings, one casing may be on the outside of the other, or a drilling pipe. The borehole may be a well, such as an exploration well, a production well or an injection well, for example. The well may be used for petroleum recovery, energy production or production of drinking water or water for irrigation purposes.
By a fluid is meant, in what follows, for example liquids like water, seawater, brine, completion fluid, drilling fluid, drilling mud and oil, or gas, and mixtures of gas and liquids .
The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.
The object is achieved through features which are specified in the description below and in the claims that follow.
In a first aspect, the invention relates to a cutting tool arranged to cut, completely or partially, an elongated body, the body extending axially in a fluid-filled, elongated cavity surrounding the cutting tool; the cutting tool being provided with a cutter arranged to cut the elongated body completely or partially; the cutter including at least one knife with a cutting edge, the knife being arranged to force the cutting edge completely or partially through the elongated body; the cutting tool including at least one axially movable piston with a first piston surface facing away from the cutter and with a second piston surface facing the cutter; the second piston surface being in fluid communication with the fluid in the elongated cavity, and the area of the first piston surface being larger than the area of the second piston surface; and a wedge-shaped portion provided with a sloping surface being arranged to move the knife towards the elongated body when the wedge-shaped portion is moved axially along the cutting tool, and the first piston surface being in fluid communication with the fluid in the elongated cavity.
By the area of the first piston surface is meant the sum of the effective, operative area of one or more surfaces that are perpendicular to the longitudinal axis of the cutting tool and that are facing away from the cutter. By the area of the second piston surface is meant the effective, operative area of one or more surfaces that are perpendicular to the longitudinal axis of the cutting tool and that are facing the cutter. For surfaces that are not perpendicular to the longitudinal axis of the cutting tool, the projected area of the surface on a perpendicular surface will constitute the effective, operative area. The operative area is the area which is in contact with the fluid in the elongated cavity.
The cutter may further include at least one axially movable wedge provided with a sloping surface arranged to move the knife against the elongated body when the wedge is moved axially along the cutting tool, the piston pushing against the wedge as the piston is being moved axially against the cutter .
The piston of the cutting tool may be constituted by several cooperating pistons. The pistons may be fixedly connected. The pistons may have piston surfaces following one behind the other in the axial direction. The cutting tool may include an axial guide forming an axial channel . An annular space at the first piston surface may be in fluid communication with the axial channel .
In an alternative embodiment, the cutting tool may include an axial guide forming a through-going channel . The axial guide with the through-going channel may be arranged to accommodate the elongated body. An annular space at the first piston surface is in fluid communication with the through-going channel .
The piston may be held fixed by at least one shear body. The cutter may include at least two knives . The cutter may include at least two wedges.
The cutting tool may be provided with an activatable clamping device arranged to hold the cutting tool fixed to the elongated body in a portion above the knife after activation of the knife. The clamping device may hold the cutting tool fixed to a portion of the cut elongated body which is positioned above a cutting point.
The at least one knife may cut the elongated body completely or partially with a cut forming an angle of between 15° and 165° to the longitudinal axis of the elongated body. In an alternative embodiment, the cut may form an angle of between 30° and 150° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 45° and 135° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 60° and 120° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 75° and 105° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 80° and 100° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form an angle of between 85° and 95° to the longitudinal axis of the elongated body. In a further alternative embodiment, the cut may form a radial cut of 90° to the longitudinal axis of the elongated body.
The invention may also include equipment for operations in a fluid-filled, elongated cavity including an elongated body extending axially in the elongated cavity, the elongated body being provided with the movable cutting tool described above.
In a second aspect, the invention relates to a method of cutting an elongated body in a fluid-filled elongated cavity, the method including:
- providing a cutting tool as described above;
- providing a desired number of shear bodies of a desired breaking strength and securing said shear bodies in the shear-body bores of the cutting tool;
- displaceably attaching the cutting tool to the elongated body ;
- moving the cutting tool down into the elongated, fluid- filled cavity; and
- positioning the cutting tool in the fluid-filled cavity, where the pressure of the fluid against the piston surfaces of the cutting tool exceeds the overall breaking strength of the shear bodies, so that a piston is moved axially against the cutter of the cutting tool, whereby a wedge-shaped portion forces the at least one knife of the cutting tool into the elongated body in order thereby to cut the elongated body completely or partially.
The method may further include adjusting the pressure of the elongated cavity from the outside of the elongated cavity. This may be carried out with pumps of a kind known per se, which are placed at the surface where the elongated cavity has its mouth.
In what follows, examples of preferred embodiments are described, which are visualized in the accompanying drawings, in which:
Figure 1 shows a view of the cutting tool in accordance with the invention positioned in a well, the pipe wall of the well being shown in section;
Figures 2A-C show on the same scale, in A, a view of the cutting tool in accordance the invention; in B, a cutaway view of the cutting tool before activation and, in C, a cut-away view after activation;
Figure 3 shows, on the same scale, but in a greater degree of detail, the same as figure 2B;
Figure 4 shows, on a larger scale, the upper half of the
cutting tool shown in figure 3;
Figure 5 shows, on the same scale as figure 4, the lower
half of the cutting tool shown in figure 3 ;
Figure 6 shows a cut-away view on the same scale as figure
1, an alternative embodiment of the tool in accordance with the invention before activation; and
Figure 7 shows, by and large, the same as figure 6, the tool after activation.
In the figures, the reference numeral 1 indicates a cutting tool in accordance with the invention. The cutting tool 1 includes an outer cylinder-shaped housing 2. In its, in the position of application, upper end portion 21, the housing 2 is provided with an upper end piece 25 and, in its lower end portion 23, the housing 2 is provided with a lower end piece 27. In the upper end portion 21 and the lower end portion 23, the inner shell surface 20 of the housing 2 is provided with a threaded portion 22. The upper end piece 25 and the lower end piece 27 are provided with an outer threaded portion 24, so that the upper end piece 25 and the lower end piece 27 may be releasably attached to the housing 2 with a screw connection. The end piece 25 and the end piece 27 are provided with an axial through-going bore 29 which is arranged to accommodate a wire, a cable or a rod 8, as shown in figure 1, and over which the cutting tool 1 may be slipped. The upper end piece 25 is provided with a sealing element 252 bearing seal- ingly against the inner shell surface 20. In a portion facing in towards the housing 2, the bore 29 of the upper end piece 25 is provided with a threaded portion 28. In the portion facing in towards the housing 2, the upper end piece 25 is further provided with a radial channel 90 extending from the bore 29 to a circular, circumferential recess 92 in the upper end piece 25 and forming an annular space 94. On its outside, the upper end piece 25 is provided with a neck 6, so that the cutting tool 1 may be fished up by a fishing tool of a known kind .
The cutting tool 1 is movable along the elongated body 8. The cutting tool 1 is lowered along the elongated body 8 in an elongated fluid-filled cavity 70 which is formed by a pipe 7. The pipe 7 may be constituted by production tubing or casing.
Internally in the housing 2, from the upper end portion 21 towards the lower end portion 23, there is a guide 3 extending axially. The guide 3 includes three substantially like guide elements, termed, in what follows, an upper guide element 30, a middle guide element 31 and a lower guide element 32. The guide 3 also includes a guide sleeve 33. In what fol- lows, the upper guide element 30 is discussed. It is understood that the discussion correspondingly applies to the guide elements 31 and 32 as well and only differing features are discussed for the guide elements 31, 32. The guide element 30 includes a tubular axial stem 34 and, in its lower portion, a radial end wall 35. The stem 34 extends from the end wall 35 towards the upper end piece 25. In its upper end portion, the stem 34 is provided with an externally threaded portion 36. The guide elements 30, 31, 32 are provided with an axial through-going channel 39 extending from the upper end portion of the stem 34 through the end wall 35. In its lower portion, the channel 39 is provided with a threaded portion 37. In its radial surface, the end wall 35 is provided with a sealing element 352 bearing sealingly against a piston 4 which will be discussed in what follows. In its upper portion, the stem 34 is provided with a radial bore 38. In its lower portion, the end wall 35 is provided with a radial channel 90' extending from the axial channel 39 to a circular, circumferential recess 92' in the end wall 35 and forming an annular space 94 ' . In its upper portion, the guide sleeve 33 is formed as the stem 34. In its lower portion, in the channel 39, the guide sleeve 33 is provided with an internally threaded portion 37'.
The upper guide element 30 is releasably screwed to the upper end piece 25 with the screw connection formed by the threaded portions 28 and 36. The threaded portions 28 and 36 are screwed together in such a way that the bore 38 coincides with the channel 90 and a continuous channel is formed from the channel 39 to the annular space 94, 94 ' . The middle guide element 31 is releasably screwed to the upper guide element 30 with the screw connection formed by the threaded portions 36 and 37. The threaded portions 36 and 37 are screwed together in such a way that the bore 38 coincides with the channel 90'. Correspondingly, the lower guide element 32 is releasably screwed to the middle guide element 31 and, correspondingly, the guide sleeve 33 is releasably screwed to the lower guide element 32.
The cutting device 1 is provided with an internal piston 4 formed by an upper piston 40, two middle pistons 41, 41' and a lower piston 42. The two middle pistons 41, 41' are of substantially like designs. Features which are common to the pistons 40, 41, 41', 42 have the same reference numerals. The piston 4 is provided with a plurality of first piston surfaces 43 extending radially from the guide 3 to an inner shell surface 444 on the side wall 44 of the piston 4. The piston 4 is provided with a central, axial, through-going bore 45. The piston 4 is circumferentially provided with a sealing element 402 bearing sealingly against the shell surface 20, and with a sealing element 404 in the bore 45. The sealing element 404 bears sealingly against the guide 3. In its upper end portion, the side wall 44 is externally stepped and provided with threads 46 in the outer shell surface 442 of the piston 4. In its lower end portion, the side wall 44 is internally stepped and provided with threads 47 in the inner shell surface 444 of the piston 4. In its outer, upper stepped portion, the side wall 44 is circumferentially provided with a sealing element 412 bearing sealingly against the lower, inner stepped portion of the side wall 44 of the piston 4 above.
The upper piston 40 differs from the piston 41, 41' by the side wall 44 of the piston 40 only being formed by a portion 44' projecting downwards. The first piston surface 43' thus extends radially from the guide 3 to the inner shell surface 20. The lower piston 42 differs from the piston 41, 41' by the downward-projecting portion 44" of the side wall 44 having been given a different form. The side wall 44" is circumfer- entially provided with a circular recess 48. After the cutting tool 1 has been assembled, the recess 48 will be flush with a radial, threaded shear-body bore 12 in the housing 2. The shear-body bore 12 and the recess 48 are arranged to accommodate a threaded shear body 14. In its lower portion, the side wall 44" forms an abutment surface 49. The abutment surface 49 also constitutes a portion of the second piston surface 490 of the piston 4. The second piston surface 490 is additionally constituted by the surface 492 between the guide sleeve 33 and the inner shell surface 446 of the downward- projecting side wall 44" of the lower piston 42, as shown in figure 5.
The pistons 40, 41, 41', 42 are releasably screwed together at the threaded connections 46, 47 so that they form one continuous piston 4. Before the shear bodies 14 are positioned in the bores 12, the piston 4 can be moved axially within the housing 2 along the guide 3.
In its lower end portion 23, the cutting tool 1 is provided with a cutter 5. The cutter 5 includes a cylinder-shaped knife holder 55 holding two knives 51, 51' and holding two wedges 53, 53'. The knife holder 55 forms an internal axial channel 59. The two wedges 53, 53' are provided with sloping surfaces 54, 54' facing inwards and are axially movable along the knife holder 55 in an axial slot 552 formed in the outer shell surface 550 of the knife holder 55. The knives 51, 51' are arranged to be moved radially in towards the centre axis of the cutting tool 1. The knives 51, 51' are formed with a crescent-shaped cutting edge (not shown) facing inwards towards the centre axis of the cutting tool 1. The knives 51, 51' are adapted with a narrow fit to a slot 56 in the knife holder 55 and are held in place in the slot 56 by friction. The knives 51, 51' are of the guillotine type, so that the cutting edges pass each other when the knives 51, 51' are moved radially.
When the cutting tool 1 has been put together, the bores 29 in the upper and lower end pieces 25, 27, the channel 39 of the guide 3 and the channel 59 of the knife holder 55 form a continuous, axial channel through the cutting tool 1. When it is necessary to cut the wire or rod 8 extending down into the elongated, fluid-filled cavity 70, the cutting tool 1 is slipped over the wire 8. By its own weight, possibly also by means of weights (not shown) which may be slipped over the wire 8 on the top side of the cutting tool 1, the cutting tool will glide along the wire 8 and down into the cavity 70. In the cavity 70, the cutting tool 1 will be surrounded on its outside by the fluid standing in the cavity 70, for example drilling fluid of a kind known per se. The fluid will also surround the wire 8 in the channel 29, 39, 59 of the cutting tool 1.
The static pressure of the fluid increases down the cavity 70. Fluid will enter the cutting tool 1 through the bore 29 and further through the bores 38 and the cannels 90, filling the annular spaces 94, 94' completely or partially. The cutting tool 1 is not fluid-tight in its lower portion 23, so that the free, upper end portions of the wedges 53, 53', the knife holder 55 and the lower portion of the guide sleeve 33 will be surrounded by fluid. The fluid in the annular space 94 will exert a pressure on the first piston surface 431 of the upper piston 40. This will be balanced by the pressure against the piston 4 from the fluid in the lower portion 23 of the cutting tool 1. The pressure in the annular spaces 94' will drive the piston 4 axially against the shear bodies 14. As the cutting tool 1 is being moved down the cavity 70, the pressure against the first piston surfaces 43 will increase. The shear bodies 14 prevent the piston 4 from moving axially relative to the housing 2. The number of shear bodies 14 may be varied and the breaking strength of the shear bodies 14 may be varied. When the pressure of the fluid against the piston 4 exceeds the overall breaking strength of the shear bodies 14, the shear bodies 14 are cut and the piston 4 moves axially towards the lower end portion 23 of the cutting tool 1. The abutment surface 49 of the lower piston 42 forces the wedges 53, 53' downwards. The sloping surfaces 54, 54' of the wedges 53, 53' force the knives 51, 51' radially inwards against the wire 8, and further into the wire 8 until this is cut, see figure 2C. Thereby it is achieved that the wire 8 is cut at a desired depth in the cavity 70.
The cutting tool 1 may further be provided with a feeder cable (not shown) which may be attached to the upper end piece 25. The feeder cable is paid out in a controlled manner, so that the cutting tool 1 is lowered in a controlled manner into the cavity 70. After the cutting tool 1 has been activated and cut the wire 8, the cutting tool 1 is hoisted up again by means of the feeder cable .
The person skilled in the art will know that the hydrostatic pressure in a cavity 70 may be increased by means of pum s. Thereby the desired cutting depth may also be adjusted by means of the pressure in the cavity 70. If the cutting tool 1 should not reach the intended depth, or the pressure is too low for the shear bodies 14 to break, the cutting tool 1 is activated by increasing the pressure in the cavity 70. If the cutting tool 1 has not reached the intended depth when the cutting tool is activated, the wire 8 will be cut higher up in the cavity 70 and at a distance from the portion in which it is stuck. The major part of the wire 8 may still be freed.
The cutting tool 1 is shown in an alternative embodiment in the figures 6 and 7. In these figures, the cutting tool 1 is shown more schematically and only the parts of the cutting tool 1 that are necessary for the understanding of the operation of the tool 1 are discussed. Parts having the same function have been given the same reference numerals as in the figures 1 to 5, but are not necessarily mentioned.
On the exterior of the housing 2, the cutting tool 1 is provided with holders 81 for the elongated body 8. The cutting tool 1 is movably connected to the elongated body 8 by means of the holders 81. The cutting tool 1 is lowered along the elongated body 8 in an elongated fluid-filled cavity 70 which is formed by a pipe 7. The pipe 7 may be constituted by production tubing or casing.
The end piece 25 is provided with an axial through-going bore 29. Internally in the housing 2, from the end piece 25 towards the lower end portion 23, a guide 3 extends axially. The guide 3 includes at least one radial end wall 35. In the figures three radial end walls 35 are shown. The guide 3 is provided with an axial, through-going channel 39 extending from the end piece 25, through the end wall 35 to below the lower end wall 35. The channel 39 is in fluid communication with the elongated cavity 70 through the bore 29. The guide 3 is provided with radial, through-going bores 38 which are positioned just below the end walls 35. The guide 3 is further provided with a radial, through-going upper bore 38' just below the upper end portion 21 of the housing 2. The upper bore 38' discharges into an annular space 94 which is formed between the outer surface of the guide 3 and the inner shell surface 20 of the housing 2. The other bores 38 discharge into the annular space 941 which is formed between the outer surface of the guide 3 and the inner shell surface 444 of the piston 4. The piston 4 is constituted by an upper piston 40, two middle pistons 41, 41' and a lower piston 42. The piston 4 is provided with a plurality of first piston surfaces 43 extending radially from the guide 3 to an inner shell surface 444 on the side wall 44 of the piston 4. The piston 4 is provided with a central, axial, through-going bore 45. The piston 4 is circumferentially provided with a sealing element 402 which bears sealingly against the shell surface 20, and with a sealing element 404 in the bore 45. The sealing element 404 bears sealingly against the guide 3. The upper piston 40 differs from the piston 41, 41' by the first piston surface 43 ' extending from the guide 3 to the inner shell surface 20.
The side wall 44 is circumferentially provided with a circular recess 48. After the cutting tool 1 has been assembled, the recess 48 will be flush with a radial, threaded shear- body bore 12 in the housing 2. The shear-body bore 12 and the recess 48 are arranged to accommodate a threaded shear body 14. In its lower portion, the piston 4 forms a second piston surface 490. In its lower portion, the piston 4 further forms a wedge 53 which is provided with a sloping surface 54 facing inwards, sloping outwards and downwards from the centre of the cutting tool 1. The sloping surface 54 forms a portion of the second piston surface 490.
In its lower end portion 23, the cutting tool 1 is provided with a cutter 5. The cutter 5 includes a knife 51. The knife 51 is provided with a sloping surface 58 facing outwards, sloping outwards and downwards from the centre of the cutting tool 1. The housing 2 is provided with a through-going opening 26 for the cutting edge 51' of the knife 51. When the cutting tool 1 has been assembled, the bore 29 in the upper end piece 25, and the channel 39 of the guide 3 and the bores 38, 38' form a continuous channel from the outside of the cutting tool 1 to the annular spaces 94, 94' above the piston surfaces 43, 43'. Whenever it is necessary to cut the wire or rod 8 extending down into the elongated, fluid-filled cavity 70, the cutting tool 1 is attached, movably, to the wire 8 with the holder 81. By its own weight, possibly also by weights (not shown) that may be slipped over the wire 8 on the top side of the cutting tool 1, the cutting tool 1 will glide along the wire 8 and down into the cavity 70. In the cavity 70, the cutting tool 1 will be surrounded on its outside by the fluid standing in the cavity 70.
The static pressure of the fluid increases down the cavity 70. Fluid will enter the cutting tool 1 through the bore 29, the channel 39 and the bores 38, filling the annular spaces 94, 94' completely or partially. The cutting tool 1 is not fluid-tight in its lower portion 23, so that the second piston surface 490 will be in fluid communication with the cavity 70 through the opening 26. The fluid in the annular space 94 will exert a pressure on the first piston surface 43 ' of the upper piston 40. This will be balanced by the pressure against the second piston surface 490 in the lower portion 23 of the cutting tool 1. The pressure in the annular spaces 94' will force the piston 4 axially against the shear bodies 14 because of the area of the first piston surface 43, 43' being larger than the second piston surface 490. As the cutting tool 1 is being moved downwards in the cavity 70, the pressure against the first piston surfaces 43 will increase. The shear bodies 14 prevent the piston 4 from moving axially relative to the housing 2. The number of shear bodies 14 may be varied and the breaking strength of the shear bodies 14 may be varied. When the pressure of the fluid against the piston 4 exceeds the overall breaking strength of the shear bodies 14, the shear bodies 14 are cut and the piston 4 moves axially towards the lower end portion 23 of the cutting tool 1. The wedge 53 of the piston 4 with the sloping surface 54 will force the knife 51 outwards against the wire 8 and further into the wire 8 until this is cut, or possibly it is nearly cut through and is divided by a remaining portion being torn. Thereby it is achieved that the wire 8 is cut at a desired depth in the cavity 70, as shown in figure 7. The cutting tool 1 may be provided with a time-controlled actuator and/or valve 60, possibly with an actuator 60 which can be activated from the surface, as shown in figure 7. The actuator 60 operates fluid-tight valves for the bore 29. When the cutting tool 1 is lowered, there will be no fluid entering the annular spaces 94 , 941. After the cutting tool 1 has been positioned and at a desired time, the actuator opens the valves so that fluid will enter the annular spaces 94, 94' and the cutting tool 1 is activated to cut the wire 8.
It is essential to the operation of the cutting tool 1 that a greater pressure is applied to the surfaces 43, 43' of the piston 4 than the pressure in a chamber 16 defined by the outer surface 310 of the guide 3, the inner shell surface 444 of the piston, the upper surface 354 of the end wall 35 and the bottom side 446 of the piston, see figure 6. The chamber 16 will maintain an atmospheric pressure while the cutting tool 1 is moved down along the elongated body 8. The sealing elements 352 and 404 prevent fluid from the cavity 70 from being able to enter the chamber 16.
In a further alternative embodiment, the cutting tool 1 may be provided with a clamping member 83 which, after the activation of the cutting tool 1, holds the cutting tool 1 fixed to a portion of the cut wire 8 above the cutting point formed by the knife 51. Thereby the cutting tool 1 can be hoisted up together with the cut wire 8 in the cavity 70. Such a radially movable clamping member 83 is shown schematically in figure 7. The clamping member 83 is accommodated in a slot 85 in the outer shell surface 442 of the piston 4. The inclined wall 87 of the slot 85 abuts against the sloping surface 89 of the clamping member 83, and the clamping member 83 will be moved radially outwards when the piston 4 is moved axially downwards towards the cutter 5. The wire 8 will be clamped between the holder 81 and the clamping member 83.
In an alternative embodiment, not shown, the annular spaces 94, 94' may be in fluid communication with the cavity 70 through openings in the wall of the housing 2. In this embodiment, there is no through-going bore 29 and no channel
39. The end walls 35 may have a cross section which is adapted to the inner diameter of the housing 2. The guide 3 may be replaced by an axial piston rod connecting the pistons
40, 41, 41', 42 and extending centrally through the end walls

Claims

C l a i m s
A cutting tool (1) arranged to cut an elongated body (8) completely or partially, the body (8) extending axially in a fluid- filled, elongated cavity (70) surrounding the cutting tool (1) ; the cutting tool (1) being provided with a cutter (5) which is arranged to cut the elongated body (8) completely or partially; the cutter (5) including at least one knife (51, 51') with a cutting edge (52), the knife (51, 51") being arranged to force the cutting edge (52) completely or partially through the elongated body (8); the cutting tool (1) including at least one axially movable piston (4) with a first piston surface (43, 43') facing away from the cutter (5) and with a second piston surface (490) facing the cutter (5) ; the second piston surface (490) being in fluid communication with the fluid in the elongated cavity (70) , and the area of the first piston surface (43, 43') being larger than the area of the second piston surface (490) ; and a wedge-shaped portion provided with a sloping surface (54, 54') being arranged to move the knife (51, 51') against the elongated body (8) as the wedge-shaped portion is being moved axially along the cutting tool (1) ,
c h a r a c t e r i z e d i n that the first piston surface (43, 43') is in fluid communication with the fluid in the elongated cavity (70) .
The cutting tool (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the cutter (5) further includes at least one axially movable wedge (53, 53') provided with a sloping surface (54, 54') arranged to move the knife (51, 51') against the elongated body (8) when the wedge (53, 53') is being moved axially along the cutting tool (1) , the piston (4) pushing against the wedge (53, 53') when the piston (4) is being moved axially against the cutter (5) .
3. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the piston (4) is formed by several cooperating pistons (40, 41, 41', 42) .
4. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the cutting tool (1) includes an axial guide (3) forming an axial channel (29, 39) .
5. The cutting tool (1) in accordance with claim 4,
c h a r a c t e r i z e d i n that an annular space (94, 94') at the first piston surface (43, 43') is in fluid communication with the axial channel (29, 39) .
6. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the cutting tool (1) includes an axial guide (3) which forms a through- going channel (29, 39, 59) .
7. The cutting tool (1) in accordance with claim 6,
c h a r a c t e r i z e d i n that the axial guide (3) is arranged to accommodate the elongated body (8) .
8. The cutting tool (1) in accordance with claim 6,
c h a r a c t e r i z e d i n that an annular space (94, 94') at the first piston surface (43, 43') is in fluid communication with the through-going channel (29, 39, 59) .
9. The cutting tool (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the piston (4) is held fixed by at least one shear body (14) .
10. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the cutter (5) includes at least two knives (51, 51 ' ) .
11. The cutting tool (1) in accordance with claim 2,
c h a r a c t e r i z e d i n that the cutter (5) includes at least two wedges (53, 531 ) .
12. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the cutting tool (1) is provided with an activatable clamping device arranged to hold the cutting tool (1) fixed to the elongated body (8) in a portion above the knife (51, 51') after activation of the knife (51, 51 ' ) .
13. The cutting tool (1) in accordance with claim 1,
c h a r a c t e r i z e d i n that the at least one knife (51, 51') cuts the elongated body (8) , completely or partially, with a cut forming an angle of between 15° and 165° to the longitudinal axis of the elongated body (8) .
14. Equipment for operations in a fluid-filled, elongated cavity (70) including an elongated body (8) extending axially in the elongated cavity (70) , c h a r a c t e r i z e d i n that the elongated body (8) is movably provided with the cutting tool (1) in accordance with claim 1.
15. A method of cutting an elongated body (8) extending axially in a fluid-filled, elongated cavity (70) , wherein the method includes : - providing a cutting tool (1) in accordance with claim 1 ;
- providing a desired number of shear bodies (14) of a desired breaking strength and securing said shear bodies (14) in the shear-body bores (12) of the cutting tool (1) ;
- displaceably attaching the cutting tool (1) to the elongated body (8) ;
- moving the cutting tool (1) down into the elongated, fluid-filled cavity (70) ; and
- positioning the cutting tool (1) in the fluid-filled cavity (70) where the pressure of the fluid against the first piston surfaces (43, 43') of the cutting tool (1) exceeds the overall breaking strength of the shear bodies (14) , so that a piston (4) is moved axi- ally against the cutter (5) of the cutting tool (1) , whereby a wedge-shaped portion forces the at least one knife (51, 51') of the cutting tool (1) into the elongated body (8) in order thereby to cut the elongated body (8) completely or partially.
The method in accordance with claim 15, wherein the method further includes adjusting the pressure of the fluid in the elongated cavity (70) from the outside of the elongated cavity (70) .
PCT/NO2012/050057 2011-04-08 2012-03-30 Cutting tool for use in fluid-filled cavities and use of the tool WO2012138231A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP12768317.5A EP2694774A4 (en) 2011-04-08 2012-03-30 Cutting tool for use in fluid-filled cavities and use of the tool

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NO20110540 2011-04-08
NO20110540 2011-04-08
NO20120391A NO334976B1 (en) 2011-04-08 2012-03-29 Cutting tool for use in fluid-filled cavities and method of cutting an elongated body in the fluid-filled cavity with the cutting tool
NO20120391 2012-03-29

Publications (1)

Publication Number Publication Date
WO2012138231A1 true WO2012138231A1 (en) 2012-10-11

Family

ID=46969413

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2012/050057 WO2012138231A1 (en) 2011-04-08 2012-03-30 Cutting tool for use in fluid-filled cavities and use of the tool

Country Status (3)

Country Link
EP (1) EP2694774A4 (en)
NO (1) NO334976B1 (en)
WO (1) WO2012138231A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104708650A (en) * 2015-03-11 2015-06-17 大庆金祥寓科技有限公司 Perforated cable cutter

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2185303A (en) * 1938-07-01 1940-01-02 Myron M Kinley Wire line shooting tool
US3926252A (en) * 1974-09-19 1975-12-16 Schlumberger Technology Corp Line cutting devices
US4909321A (en) * 1988-12-27 1990-03-20 Conoco Inc. Wireline releasing device
WO2004038171A1 (en) * 2002-10-24 2004-05-06 Welltec Aps Method for releasing cables from an attached well tool and apparatus for exercising the method
US6763753B1 (en) * 2000-10-06 2004-07-20 Baker Hughes Incorporated Hydraulic wireline cutter
US7264060B2 (en) * 2003-12-17 2007-09-04 Baker Hughes Incorporated Side entry sub hydraulic wireline cutter and method
US20100181072A1 (en) * 2009-01-21 2010-07-22 Peter Gillan Downhole Well Access Line Cutting Tool

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1491610A (en) * 1920-10-05 1924-04-22 Alice Double Wire-line cutter
US4512411A (en) * 1984-04-19 1985-04-23 Camco Incorporated Fluid actuated energy charged well service line cutter
US4886115A (en) * 1988-10-14 1989-12-12 Eastern Oil Tools Pte Ltd. Wireline safety mechanism for wireline tools
NO20070217A (en) * 2007-01-12 2008-06-30 Smart Installations As Cutting device and method for emergency cutting of a pipe in a well
US8333236B2 (en) * 2009-05-20 2012-12-18 Baker Hughes Incorporated Auxiliary conduit cutting apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2185303A (en) * 1938-07-01 1940-01-02 Myron M Kinley Wire line shooting tool
US3926252A (en) * 1974-09-19 1975-12-16 Schlumberger Technology Corp Line cutting devices
US4909321A (en) * 1988-12-27 1990-03-20 Conoco Inc. Wireline releasing device
US6763753B1 (en) * 2000-10-06 2004-07-20 Baker Hughes Incorporated Hydraulic wireline cutter
WO2004038171A1 (en) * 2002-10-24 2004-05-06 Welltec Aps Method for releasing cables from an attached well tool and apparatus for exercising the method
US7264060B2 (en) * 2003-12-17 2007-09-04 Baker Hughes Incorporated Side entry sub hydraulic wireline cutter and method
US20100181072A1 (en) * 2009-01-21 2010-07-22 Peter Gillan Downhole Well Access Line Cutting Tool

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2694774A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104708650A (en) * 2015-03-11 2015-06-17 大庆金祥寓科技有限公司 Perforated cable cutter

Also Published As

Publication number Publication date
EP2694774A4 (en) 2016-01-06
EP2694774A1 (en) 2014-02-12
NO20120391A1 (en) 2012-10-09
NO334976B1 (en) 2014-08-11

Similar Documents

Publication Publication Date Title
US10202814B2 (en) Downhole tool with expandable stabilizer and underreamer
EP2206877B1 (en) Downhole cable gripping/shearing device and method
US5924489A (en) Method of severing a downhole pipe in a well borehole
EP0604568B1 (en) Downhole activated system for perforating a wellbore
NO314732B1 (en) Method and apparatus for centering a pipe into a well
US5165478A (en) Downhole activated process and apparatus for providing cathodic protection for a pipe in a wellbore
BRPI0903389A2 (en) multi-cut coating methods
US10544655B2 (en) Method and apparatus for severing a drill string
EP3830379B1 (en) Improvements in or relating to well abandonment and slot recovery
US7325612B2 (en) One-trip cut-to-release apparatus and method
EP1998001A2 (en) Perforating torch apparatus and method
US10119349B2 (en) Redundant drill string cutting system
GB2492919A (en) A vibrating downhole tool having differing turbine blades
CN109790744A (en) Improved preventer
US20230287751A1 (en) System for dislodging and extracting tubing from a wellbore
WO2013033306A9 (en) Well emergency separation tool for use in separating a tubular element
US8579022B2 (en) Apparatus for deploying and activating a downhole tool
US20110226474A1 (en) Method and apparatus for cutting tubular goods
EP2694774A1 (en) Cutting tool for use in fluid-filled cavities and use of the tool
US7353868B2 (en) Wireline coupler
WO2015009283A1 (en) Systems and methods for minimizing impact loading in downhole tools
EP3559400B1 (en) Downhole apparatus and methods
NO333219B1 (en) Device by cable cutter
US11993995B2 (en) Tubular cutting and fishing tool
US20240200418A1 (en) External intervention downhole drilling and workover tool

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12768317

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

REEP Request for entry into the european phase

Ref document number: 2012768317

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 2012768317

Country of ref document: EP