Single acting hydraulic fishing jar

Description

[0001] This invention relates to new and useful improvements in fishing jars and more particularly to single acting hydraulic fishing jars and the like.

[0002] A fishing job, in oilfield terminology, means removing something from the well bore that does not belong there. What is removed is called a "fish" and may be part of a drilling string which has become stuck when drilling an oil or gas well, or may be production equipment being removed from an existing well bore during a workover or repair operation. The accepted method of retrieving a fish is to grab it by some means and push or pull an axial strain on it until something gives. A jar is a tool employed when either drilling or production equipment has become stuck to such a degree that a straight push or pull from the surface is unsufficient to dislodge it.

[0003] The jar is normally placed in the pipe string in the region of the stuck object and allows the drilling rig operator at the surface to deliver an impact blow at the fish through manipulation of the drill pipe string. Jars contain a spline joint which allows relative axial movement between an inner mandrel or housing and an outer housing without allowing relative rotational movement.

[0004] The mandrel, or inner housing contains an impact surface or hammer, which contacts a similar impact surface or anvil on the housing when the jar has reached the limit of axial travel. If these impact surfaces are brought together at high velocity, they transmit a very substantial impact to the fish due to the mass of the pipe above the jar.

[0005] Prior art jars of three distinct forms, viz. hydraulic jars, mechanical jars and bumper jars. The bumper jar is used primarily to provide a downwardly directed impact blow. The bumper jar is usually a splined joint with sufficient axial travel allowed so that the pipe can be lifted and dropped, causing the impact surfaces inside the jar to come together to deliver a downward impact blow to the fish.

[0006] Mechanical and hydraulic jars differ from the bumper jar in that they contain a tripping mechanism which retards the motion of the impact surfaces relative to each other until an axial strain has been applied to the pipe. To jar upward, the pipe is stretched by an axial tensile pull applied at the surface. This tensile force is resisted by the tripping mechanism of the jar long enough to allow the pipe to stretch and store potential energy. When the jar "trips", this stored energy is converted to kinetic energy causing the impact surface of the jar to move together at a high velocity. Hydraulic and mechanical jars are much more efficient than bumper jars because they allow a much greater impact at the fish for a given pipe strain.

[0007] Mechanical jars are generally less versatile and reliable than hydraulic jars. One design of mechanical tripping mechanism requires that the tripping load be selected and preset at the surface to trip at one specific load. If it is desired to increase or decrease the tripping load, it is necessary to pull the pipe from the well bore, a costly and time consuming procedure. Another mechanical tripping mechanism of known configuration requires that torque be applied from the surface through the pipe to the tripping mechanism and that this torque be maintained while the jar trips. This can be dangerous to personnel on the rig floor and makes the tripping load difficult to control in deviated well bores. Another weakness of mechanical tripping devices is that they must be run in the cocked or detent position. Thus, the tripping mechanism is subjected to stresses during the normal course of drilling if it is run as a part of the bottom hole assembly. Mechanical tripping mechanisms have the additional disadvantage that the metallic parts must move relative to each other while under a high compressive load. This causes rapid wear and frequent failure of the moving parts.

[0008] Hydraulic tripping mechanisms are more desirable because they afford the versatility of a variable hitting load controlled only by the amount of axial strain applied at the surface. Also, hydraulic tripping mechanisms are less subject to mechanical deformation and wear than mechanical tripping mechanisms and therefore will work for a longer time under the same conditions.

[0009] The patent literature disclosing hydraulic jars has developed largely within the last thirty years.

[0010] U.S.-A-3,349,858 discloses a single acting (upward) hydraulic drilling jar in which the oil flow through the piston is controlled by a constant flow regulator valve.

[0011] U.S.-A-3,735,827 discloses a hydraulic fishing jar requiring a compressible hydraulic fluid. The mandrel is moved until the hydraulic fluid is compressed to a selected degree at which point a control valve engages an adjustable tripping abutment which opens the valve and dumps the pressurized fluid through a bypass to permit rapid movement of the hammer relative to the anvil surface.

[0012] U.S.-A-3,797,591 discloses a hydraulic fishing jar similar to US-A-3,735,827 but including a different adjustable trigger mechanism.

[0013] U.S.-A-3,851,717 discloses a hydraulic fishing jar having a constant flow bypass for a tripping piston and arranged so that the tripping piston is moved down until the main bypass valve is opened and the device trips.

[0014] U.S.-A-4,059,167 discloses a fishing jar similar to U.S.-A-3,851,717 and incorporating a tandem piston arrangement to lower the internal operating pressure.

[0015] U.S.-A-3,285,353 discloses a fishing jar having telescoping mandrels, one connected to the drill string and the other to the drill fish, surrounded by an outer housing. A piston valve is arranged to dump pressure after a selected degree of movement and to move the housing to impact a hammer surface against an anvil su rface.

[0016] U.S.-A-3,087,559 discloses a hydraulic fishing jar having mechanical trip fingers with a hydraulic delay.

[0017] GB-A-2,089,400 discloses a double acting drilling jar having telescoping members with a hammer member on one of them and an anvil member on the other of the telescoping members. A piston operatively connected to one of said telescoping members is provided to close a chamber formed therebetween and to be movable in said chamber for pressurization thereof. Valve means are provided for closing a valve opening in one of said telescoping members and moveable to open same to release fluid from the chamber, as well as means for actuating said valve means.

[0018] The object of the invention is to provide an improved fishing jar useful in earth drilling operations for removing stuck objects or "fish" from a drill hole.

[0019] This object is achieved according to the invention in a fluid actuating fishing jar as described in the preamble of claim 1 by the features recited in the characterizing part of claim 1.

[0020] Useful embodiments of the invention are claimed in the claims 2 to 15.

[0021] The invention will now be described by way of example with reference to the accompanying drawings wherein:

Figs. 1A-1 D are successive portions, in quarter section, along the length of a single acting hydraulic fishing jar showing a preferred embodiment of this invention in an initial or starting position;

Fig. 2 is a view in half cross section of the fishing jar taken on the section line 2-2 of Fig. 5B;

Fig. 3 is a view in half cross section of the fishing jar taken on the section line 3-3 of Fig. 5B;

Fig. 4 is a view in half cross section of the fishing jar taken on the section line 4-4 of Fig. 5C; and

Figs. 5A-5D correspond substantially to Figs. 1A-1D showing the position of the apparatus after the tripping valve has been opened and the mandrel has moved to the fully actuated position with the hammer striking the anvil portion thereof.

[0022] Referring to the drawings, and particularly to Figs. 1A-1D, inclusive, there is shown a single acting fishing jar 1 which is of substantial length necessitating that it be shown in four successive longitudinally broken quarter sectional views, viz. Figs. 1A, 1B, 1C and 1D. Each of these views is shown in longitudinal section extending from the center line of the jar to the outer periphery thereof. Fishing jar 1 comprises inner tubular mandrel 2 telescopingly supported inside outer tubular housing 3. Mandrel 2 and housing 3 each consist of a plurality of segments or parts which must be described in further detail.

[0023] Mandrel 2 consists of an upper tubular portion 4 (in Figs. 1A and 1 B) having an inner longitudinal passage 5 extending therethrough. The upper end of upper portion 4 is enlarged as indicated at 6. and is internally threaded at 7 for connection to a drill string or the like. The lower end of mandrel portion 4 is provided with a counterbore ending in internal shoulder 8 and internally threaded as indicated at 9.

[0024] An intermediate portion of mandrel 2 consists of tubular sleeve member 10 (in Figs. 1B and 1C) which has its upper end threaded as indicated at 11 for connection inside threaded portion 9 of member 4 with the upper end portion abutting shoulder 8. The lower end of sleeve member 10 is threaded externally as indicated at 12 (Fig. 1C) and is provided with an internal bore or passage 13 which is a continuation of passage 5 in mandrel portion 4. The lower end of mandrel 2 consists of tubular member 14 (in Figs. 1C and 1D) which is provided with a counterbore ending in shoulder 15 and internally threaded as indicated at 16. Tubular portion 14 is threadedly assembled on the lower end of tubular member 10 with the lower end thereof abutting shoulder 15.

[0025] The lower end portion of tubular member 14 is of reduced diameter as indicated at 17 defining an annular stop shoulder 18. Tubular portion 14 has an internal longitudinal passage 19 which is an extension of passages 5 and 13. The three portions 4, 10 and 14 are threadedly assembled, as shown, into a single tubular mandrel 2 which is longitudinally movable inside tubular housing 3 as will be subsequently described.

[0026] Tubular housing 3 is formed in several sections, for purposes of assembly, somewhat similarly to mandrel 2. The upper end of tubular housing 3 consists of tubular member 20 (in Fig. 1A) which has a smooth inner bore 21 at its upper end in which the exterior surface 22 of upper mandrel tubular member 4 is positioned for longitudinal sliding movement. The lower end portion of tubular housing member 20 has a portion of reduced diameter forming an annular shoulder 23 and having an exterior threaded 'portion 24.

[0027] Tubular housing 3 is provided with an intermediate tubular portion 25 (in Figs. 1A and 1B) which is internally threaded as indicated at 26 at its upper end "for threaded connection to the threaded portion 24 of tubular housing member 20. The upper end of the intermediate tubular portion 25 abuts shoulder 23 when the threaded connection is made up tight. The lower end portion of tubular member 25 has a portion of reduced diameter (Fig. 1B) forming shoulder 27 and externally threaded as indicated at 28.

[0028] The lower portion of tubular housing 3 consists of tubular member 29 (in Figs. 1B, 1C and 1D) which is internally threaded as indicated at 30 at its upper end for threaded connection to the threaded portion 28 of intermediate housing portion 25. The upper end of the lower tubular housing portion 29 abuts shoulder 27 when the threaded connection is made up tight. The lower end of tubular housing portion 29 is internally threaded as indicated at 31 (in Fig. 1D).

[0029] At the lower end of tubular housing 2, there is provided an elongated tubular connecting member or sub 32 which is externally threaded, as indicated at 33, at its upper end and has a shoulder 34 against which the lower end of tubular housing member 29 abuts when the threaded connection 31/33 is made up tight. Connecting sub 32 has an inner longitudinal passage 35 which is a continuation of the passages through mandrel 2 and which also communicates with the annular space between mandrel portion 14 and the inner surfaces of housing portion 29 and sub 32. The lower end of sub 32 is of reduced diameter as indicated at 36 and has a threaded surface 37 for connection to a fish, or the like, for operation as a fishing jar.

[0030] As has already been noted, the mandrel 2 and housing 3 are each formed of several threadedly connected sections for purposes of assembly. Mandrel 2 is arranged for sliding movement inside housing 3. The apparatus will be charged with a suitable operating fluid, e.g. hydraulic fluid, as will be subsequently described, and it is therefore necessary to provide seals against leakage from several points of assembly and also from the points of sliding engagement between mandrel 2 and housing 3.

[0031] As previously noted, the exterior surface of the upper mandrel portion 4 has a sliding fit in the bore 21 of the upper tubular portion 20 of housing 3. Tubular member 20 is provided with an internal annular groove 38 in which there is positioned an O-ring 39 which seals that sliding joint against leakage of hydraulic fluid. The threaded connection between tubular housing portions 20 and 25 is sealed against leakage by an O-ring 40 (in Fig. 1A) which is positioned in external peripheral groove 41 in the lower end of tubular housing member 20. The threaded connection between tubular housing members 25 and 29 is similarly sealed against fluid leakage by an 0-ring 42 (in Fig. 1B) which is positioned in peripheral groove 43 in the lower end portion of housing member 25. The threaded connection between the lower end of tubular housing member 29 and connecting sub 32 is similarly sealed against leakage in fluid by 0-ring 44 (in Fig. 1D) positioned in annular groove 45 in the upper end of sub 32.

[0032] Similar seals are provided to prevent leakage through the threaded joints connecting the several sections of mandrel 2. The threaded connection between upper tubular portion 4 and intermediate tubular portion 10 of mandrel 2 is sealed against leakage by O-ring 46 (in Fig. 1B) which is positioned in inner annular groove 47 in the lower end portion of the upper tubular mandrel member 4. The threaded connection between intermediate tubular mandrel member 10 and lower tubular mandrel member 14 is similarly sealed against leakage by O-ring 48 (in Fig. 1C) which is positioned in inner circumferential groove 49.

[0033] The space between the inner bore of the various components of housing 3 and the external surface of mandrel 2 provides an enclosed chamber and passages for flow of hydraulic fluid (or other suitable operating fluid) through this fishing jar. Various additional components are provided as will be subsequently described. At the upper end of tubular housing member 20, the space between the inner bore 50 thereof and the external surface 22 of mandrel tubular member 4 provides an annular space or chamber 52. The upper end of chamber 52 is provided with a threaded opening 53 in which a threaded plug member 54 is secured. Threaded opening 53 provides for the introduction of hydraulic fluid (or other suitable operating fluid) as will be subsequently described.

[0034] The exterior surface of tubular mandrel member 4 is of slightly reduced diameter at the lower end portion 55 thereof and is provided with a plurality of longitudinally extending grooves 56 with splines 57 therebetween (in Figs. 1A and 2). The lower end portion of housing tubular member 20 is provided with an inner bore 58 of reduced diameter forming an upper beveled shoulder 59 and having a plurality of' longitudinally extending grooves 60 therein circumferentially spaced to define a plurality of splines 61 which fit into grooves 56 in upper tubular mandrel member 4 (in Figs. 1A and 2).

[0035] The grooves 56 and 60 in tubular housing member 20 and in tubular mandrel member 4 are of greater depth than the height of the splines 57 and 61 positioned in those grooves. As a result, passages are provided which extend longitudinally of the respective grooves in mandrel member 4 and housing member 20 as indicated at 62 and 63 (in Figs. 1A and 2).

[0036] The arrangement of longitudinally extending splines and grooves in tubular housing member 20 and on tubular mandrel member 4 provides a guide for longitudinal movement of mandrel 2 in housing 3 without permitting rotary movement therebetween. The passages 62 and 63 in the clearance between the splines and grooves provide for flow of hydraulic fluid between chamber 52 and the lower portions of the apparatus as will be subsequently described.

[0037] In Fig. 1 B, it is seen that the clearance between tubular housing member 25 and mandrel member 4 is such that there is provided a hydraulic chamber 64 of substantially enlarged size relative to hydraulic chamber 52 and communicating therewith. The lower end of tubular housing member 20 provides an anvil surface 65 which is utilized when this apparatus jars in an upward direction for fishing an object from a well. The inner surface 66 of tubular housing member 25 constitutes a counterbore which produces an internal circumferential shoulder 67 at the lower end of hydraulic chamber 64 which is a stop limiting downward movement of the mandrel into the housing.

[0038] The lower end portion 68 of mandrel member 4 has the external surface 55 thereof threaded as indicated at 69. A hollow cylindrical hammer 70, having internal threads 71, is threadedly secured on the threaded portion 69 of tubular mandrel member 4 and may be secured against loosening during operation by a set screw or the like (not shown). The upper end portion 72 of hammer 70 is engageable during operation with the anvil surface 65 on housing member 20. The lower hammer surface 73 of hammer member 70 engages stop shoulder 67 at the limit of downward operation of the apparatus. Housing member 25 has an upper counterbore 74 and a lower counter-bore 75 which end a short distance apart and define an intermediate portion 76 forming a guide for movement of the mandrel.

[0039] Tubular mandrel portion 10 is provided with a plurality of longitudinally extending grooves 77 (in Figs. 1B, 1C and 3). Grooves 77 provide flow passages for flow of hydraulic fluid as will be subsequently described. Tubular sleeve member 78 fits tightly on tubular mandrel member 10 overlying the upper end portions of grooves 77. The lower end portion of sleeve member 78 has an enlarged portion 79 with a beveled surface forming a valve seat 80 (in Figs. 1B and 3).

[0040] Tubular sleeve member 78 is provided with apertures 81 at its upper end which open from counterbore 74 into grooves 77. It is also provided with apertures 82 which open from the lower ends of grooves 77 into hydraulic chamber 83, controlled by a tripping valve 84, as described below. The upper end of tubular sleeve member 78 abuts the lower end of tubular mandrel member 4. The lower end of tubular member 78, below valve seat 80, abuts the upper end of a tubular sleeve member 85 which fits tightly over the mandrel member 10 covering the lower end portions of grooves 77. Sleeve members 78 and 85 therefore enclose the grooves 77 and define a system of longitudinally extending passages. The lower end of sleeve 85 is enlarged, as indicated at 86 and has a plurality of apertures 87 opening from the lower ends of grooves or passages 77.

[0041] The inner surface 88 of housing member 29 and the outer surfaces of tubular sleeve members 78 and 85 are spaced apart to define a hydraulic chamber 83. The outer surface of sleeve member 85 is a smooth cylindrical surface permitting free movement of a pressure piston 89 and a tripping valve 84 supported therebetween. The lower end portion of sleeve member 85 is enlarged, as indicated at 90, and is provided with slots 91 in the outer surface thereof. The upper end of hydraulic chamber 83, at guide portion 76 of housing member 25 is sealed by O-ring 92 positioned in annular groove 93.

[0042] Approximately midway of the length of hydraulic chamber 83, there is provided a tripping valve 84 (in Figs. 1B and 5C) for controlling the release of hydraulic fluid from the chamber 83. Tripping valve 84 is a tubular valve member having a smooth cylindrical bore 94 fitting the outer surface of tubular sleeve 85 for sliding movement thereon. Valve member 84 is sealed on its inner surface by O-ring 95 fitting in annular groove 96. Valve member 84 has an enlarged tubular extension 97 having a counterbore 98. Apertures 99 open from counterbore 98 into hydraulic chamber 83. Valve member 84 has a beveled valve seat surface 100, connecting smooth cylindrical bore 94 and counterbore 98, which has an initially closed position against valve seat 80.

[0043] An annular pressure piston 89 is positioned at the lower end of hydraulic chamber 83 (in Fig. 1C). Piston 89 has a sliding fit between tubular member 85 and the inner surface 88 of housing member 29 and is sealed on the outside by O-ring 101 positioned in groove 102. Piston 89 has a longitudinal passageway 103 with an orifice 104 therein. There are grooves 91 in an enlarged portion of sleeve 85 over which piston 89 slides which permit flow of hydraulic fluid. A coil spring 106 is positioned between piston 89 and tripping valve member 84 which urges valve member 84 to a seated position and hydraulic piston member 89 toward an initial position seated on shoulder 107.

[0044] Below the shoulder 107 on which pressure piston 89 rests, there is a fluid chamber 108 (in Fig. 1C) formed by the outer surface 109 of mandrel portion 14 and the inner surface 110 of housing portion 29. The lower end of fluid chamber 108 is closed by annular piston 111 positioned for sliding movement therein. Piston 111 is sealed against fluid leakage by O-rings 112 and 113 positioned in grooves 114 and 115, respectively. Piston 111 abuts and is urged upward by spring 116 which is supported on the upper end 117 of connecting sub 32. A threaded opening 118, closed by plug 119 provides for filling chamber 108 with fluid.

[0045] The apparatus described above is a single acting hydraulic fishing jar which can be used to apply upwardly directed impact or jarring forces to an object stuck in a well, i.e. a "fish". In the operation of this fishing jar for jarring in the upward direction, the drill pipe is stretched by an axial tensile pull applied at the surface. The application of this tensile force is resisted by the tripping mechanism of the jar long enough for the pipe to stretch and store potential energy. When the jar reaches a tripping position, the stored energy in the stretched pipe is converted to kinetic energy which causes the impact surfaces, i.e. hammer and anvil, of the jar to move together and strike at a high velocity, thus applying a very high impact force. When the upward stretch of the pipe is released, the jar is recocked to its initial or starting position. The apparatus described above is a novel fishing jar which operates in the upward direction and is tripped hydraulically. The principle of operation and the sequence of movement of the various parts will be described below to provide a clearer understanding of the invention.

[0046] When the fishing jar 1 is assembled, as described above, it is filled with a hydraulic fluid through opening 53 in the upper tubular housing member 20 and opening 118 in the lower housing member 29. The hydraulic fluid used is preferably a non-compressible fluid since the apparatus operates utilizing the leakage of fluid past the pressure piston. With certain adjustments in operating clearances, the apparatus can be operated using the well drilling fluid. While non-compressible fluids are preferred, it is possible to use a compressible hydraulic fluid or a high pressure gas, but this would require a longer tool in order to allow for the additional travel required to pressurize a compressible fluid.

[0047] When the hydraulic fluid is introduced into the fishing jar 1 through openings 53 and 118, it flows to the bottom of hydraulic fluid chamber 108 which is closed by pressure balancing piston 111. The hydraulic fluid fills the space in hydraulic chamber 108 and hydraulic chamber 83 which is located between the pressure piston 89 and O-ring seal 92. The hydraulic fluid also fills the various passages including passage 77 and counterbore 74 leading to hydraulic fluid chamber 64. This chamber is filled with fluid on up into hydraulic fluid chamber 52 in which the fluid extends up to the level of the filling opening 53.

[0048] The apparatus can be inclined somewhat to work out air bubbles in the filling so that it is completely filled with fluid up to the opening 53. At this point, filling plugs 54 and 119 are inserted and the apparatus is ready for use. The pressure balancing piston 111 allows for thermal expansion of the fluid and also allows the hydrostatic pressure of the fluid in the well bore which surrounds the jar to keep the fluid in the jar under sufficient pressure to cause it to complete its path of flow fron one section of the apparatus to another.

[0049] In the embodiment of the invention as shown in Figs. 1A-1D, the apparatus is in the initial or starting position from which it can be moved upward to produce an upward jarring force to facilitate loosening a "fish". In this initial position, the hammer 70 is positioned against stop shoulder 73. The pressure piston 89 is held against shoulder 107 by the force of spring 106. In this position, the spring 106 also holds tripping valve 84 in closed position against valve seat 80 (in Fig. 1B). The apparatus will be first described in providing an upward jarring action for loosening a "fish".

[0050] When this fishing jar is operated in an upward direction from the initial position shown in Figs. 1A-1D, the drill string to which the upper end 6 of mandrel 2 is attached is stretched upward and placed under the desired degree of tension. As the drill string is streched upward, it places the mandrel 2 under tension and moves it to the limit permitted by the tripping mechanism. The upward movement of mandrel 2 from the initial or starting position shown in Figs. 1A-1D, first brings the shoulder of the enlarged portion 86 of sleeve member 85 into engagement with the bottom end of pressure piston 89. In this position the shoulder of enlarged portion 86 and piston 89 function as a valve closing the end of chamber 83 which prevents the flow of fluid from the chamber except through passage 104. This initial upward movement by mandrel 2 does not yet start to actuate tripping valve 84 or apply any pressure to the fluid in the system.

[0051] As mandrel 2 moves further upward, the shoulder moves pressure piston 89 upward to apply pressure to the fluid in chamber 83. Further movement of pressure piston 89 upward, by movement of mandrel 2, results in the resistance to movement building up because of the relative incompressibility of the hydraulic fluid which fills chamber 83. When pressure piston 89 moves upward, pressure is applied to the fluid in chamber 83 and a very high hydraulic pressure is rapidly achieved. The fluid can not flow past O-ring seal 92 or out through tripping valve 84 which is closed at this stage of operation. The fluid in chamber 83 can only leak very slowly through passage 103 and orifice 104 in pressure piston 89. This permits upward movement of piston 89 at a rate determined by the amount of fluid which has leaked from chamber 83 through passage 103. During this upward movement, the hydraulic fluid in chamber 83 is maintained under a very high pressure which represents the pressure created by the tension applied to mandrel 2 from the drilling string.

[0052] Further upward movement of mandrel 2 moves the pressure piston 89 relative to housing portion 29 and relative to the 0-ring seal 92. Such movement is permitted by the slow leakage of fluid from chamber 83 through orifice 104 into chamber 108 and through passages 77 into chamber 64 beyond the 0-ring seal 92. After predetermined upward movement, the apparatus reaches the position where the end of the enlarged portion 97 of tripping valve 84 engages the lower end 120 of housing member 25. The position just described is an intermediate position, not shown in the drawings, just prior to tripping the valve.

[0053] At this point, the hydraulic fluid in chamber 83 is under a very high pressure and is resisting movement of piston 89 which provides the resistance to movement of mandrel 2 allowing the build up of a substantial amount of tension in the mandrel and in the drill string. When mandrel 2 moves further upward, the movement of tripping valve 84 along with the mandrel is restrained and valve surface 100 moves away from valve seal 80 to open tripping valve 84. In this position, the end of valve member enlarged portion 97 abuts the lower end 120 of housing member 25. Tripping valve 84 is open and fluid is free to flow through apertures 99 and 82 and the various passages communicating with the other fluid chambers 108, 64, and 52. When tripping valve 84 is opened, the fluid in chamber 83 is released to flow to the other fluid chambers, primarily chambers 108 and 64, and the pressure in chamber 83 drops substantially to the level of the hydrostatic pressure in the well bore. This pressure drop removes the resistance to upward movement by pressure piston 89 and permits that piston and mandrel 2 to move, rapidly for the remaining length of the jarring stroke.

[0054] This last rapid movement is the movement between the position where the tripping valve 84 starts to open and the position shown in Figs. 5A to 5D. This movement is one in which the tripping valve has been opened wide, as seen in Figs. 5B and 5C, and mandrel 2 has moved upward to the point where the upper surface 72 of hammer 70 has engaged anvil shoulder 65 with a hammer or impact blow. This last rapid movement releases the tensile energy in mandrel 2 and the drill string in the form of kinetic energy moving hammer 70 at a very high speed into jarring impact with anvil shoulder 65. At the point of engagement of hammer 70 with anvil shoulder 65, the apparatus has reached the point of maximum upward movement. The movement of mandrel 2 is thus limited in an upward direction by engagement of hammer 70 with anvil shoulder 65 and in a downward direction by engagement of hammer 70 with stop shoulder 67, as previously described.

[0055] After reaching the upward limit of movement shown in Figs. 5A to 5D, the apparatus is recocked for further use by releasing the tension of the drill string to allow the mandrel 2 to move back to the initial or starting position of Figs. 1A-1D. As mandrel 2 moves downward, hammer 70 moves away from anvil surface 65. Pressure piston 89 moves downward along with mandrel 2. Fluid chamber 83 is filled with hydraulic fluid forced by the downward movement of pressure piston 89 through opening 87, passages 77, apertures 82, and the open tripping valve 84. When the downward movement of the mandrel moves tripping valve 84 away from the end 120 of housing member 25, tripping valve 84 closes. Continued downward movement of mandrel 2 causes pressure piston 89 to contact shoulder 107 and open the valve formed by piston 89 and the shoulder 86 or sleeve member 65. Hydrostatic pressure acting on piston 111 forces fluid through the open valve into chamber 83 to ensure that it is full of fluid. Further downward movement of the mandrel allows the fluid to distribute between chamber 108 and chambers 52 and 64 until the apparatus has returned to the initial or starting position shown in Figs. 1A to 1D where further downward movement is stopped by engagement of hammer 70 with stop shoulder 67.

Claims

1. A fluid actuated fishing jar comprising

a pair of tubular members (2, 3) positioned in telescoping relation for limited longitudinal movement of one relative to the other and adapted for connection of one tubular member (2) to a drill pipe and the other tubular member (3) to an object to be dislodged from a well,

means (78, 85) disposed on one of said tubular members (2, 3) defining a chamber (83) between said tubular members (2, 3)

piston means (89) closing said chamber (83) and operatively connected to one of said tubular members (3) for movement thereby,

a substantially incompressible hydraulic fluid being filled in said chamber (83) and resisting relative movement of said piston means (89),

said piston means (89) being movable in one direction to apply pressure to fluid in said chamber (83) upon relative movement between said tubular members (2, 3) in one direction,

one of said tubular members (2, 3) having a valve opening (82) positioned between said piston means (89) and the end of said chamber,

valve menas (84) initially closing said valve opening (82) and movable to open the same to release fluid from said chamber (83) upon a first predetermined relative movement of said piston means (89) in said one direction and thereby reduce substantially the resistance to further relative movement of said piston means (89) and movement of said tubular members (2, 3) therewith,

passage means (103) permitting a relatively minute flow of fluid from said chamber (83) during said first predetermined relative movement of said piston means (89), and

hammer (70) and anvil (65) means engageable with a jarring impact upon said further relative movement of said tubular members (2,3), characterized by

fixed abutment means (120) on one of said tubular members (2, 3) operatively engageable with said valve means (84) upon said first predetermined relative movement of said piston means (89) in said one direction.

2. A fishing jar according to claim 1 in which said hammer and anvil means include a hammer member on one tubular member and an anvil member on the other tubular member engageable with an impact force in one direction after a second predetermined relative movement of said tubular members in said one direction.

3. A fishing jar according to claim 1 or 2, in which said fluid flow permitting passage.means comprises at least one passageway associated with said piston means and operable during said first predetermined relative movement of said tubular members to release fluid from said chamber.

4. A fishing jar according to claim 3 in which said fluid flow permitting passageway is located in said piston means.

5. A fishing jar according to any one of the claims 1 to 4 in which said valve means comprises a valve member supported on one of said tubular members and closing said valve port, and resilient means cooperable with said valve member urging the same to an initially closed position.

6. A fishing jar according to any one of the claims 1 to 5, in which said tubular members comprise an inner tubular mandrel and an outer tubular housing.

7. A fishing jar according to claim 6 in which said inner tubular mandrel includes a plurality of equally spaced longitudinally extending splines and grooves on the external surface thereof,

said outer tubular housing includes a plurality of equally spaced longitudinally extending splines and grooves in the inner surface thereof,

the splines on each tubular member being of a size and shape fitting the grooves on the other tubular member, and

said splines and grooves being operable to permit longitudinal movement of said tubular members while preventing relative rotational movement therebetween.

8. A fishing jar according to claim 7 in which said hammer member has a plurality of equally spaced splines and grooves fitting the splines and grooves of said outer tubular member for longitudinal movement therein.

9. A fishing jar according to claim 6 in which said valve opening is in said inner tubular mandrel and

said valve member surrounds and is slidably movable on said inner tubular mandrel to control said valve opening to release fluid from said chamber, said valve member being movable with said inner tubular mandrel on movement thereof relative to said outer tubular housing.

10. A fishing jar according to claim 9 in which said tubular members enclose a second chamber (64, 108) communicating with said first named chamber through said valve opening (82), and said valve means (84) opening movement is operable to release fluid to flow from said first named chamber (83) to said second chamber (108).

11. A fishing jar according to any one of the claims 6 to 10 in which said outer tubular housing includes fixed abutment means.

12. A fishing jar according to claim 10, including seal means (111) cooperable with said tubular members to define said second chamber therebetween, and wherein the chamber defining means (78, 85) includes,

means for moving said piston means (89) in response to relative movement of said tubular members in one direction.

13. A hydraulic fishing jar according to claim 12, including

a passageway extending (77) from one end portion (64) to the other end portion (108) of said second chamber, around said first named chamber (83), to permit fluid flow therebetween.

14. A hydraulic fishing jar according to claim 9 in which

said piston means comprises an annular piston member surrounding said inner tubular mandrel and fitting within said outer tubular housing,

said piston member being movable relative to each of said tubular members,

said valve means comprising a valve member held in closing engagement at least in part by fluid pressure in said chamber and

spring means cooperable with said valve member urging the same closed position.

15. A hydraulic fishing jar according to claim 12, in which

further seal (92 comprise a seal between said tubular members at one end of said chamber permitting longitudinal sliding movement, said inner tubular mandrel has a shoulder engageable with said piston member to move the same toward said seal in response to relative movement of said tubular members in one direction and providing lost motion between said inner tubular mandrel and said valve member.

Ansprüche

1. Hydraulische Schlagschere mit einem Paar rohrförmiger Elemente (2, 3), welche teleskopisch ineinander angeordnet sind, um eine begrenzte Längsbewegung des einen bezüglich zu dem anderen zuzulassen und zur Verbindung eines rohrförmigen Elementes (2) mit einem Bohrgestänge und des anderen rohrförmigen Elementes (3) mit einem aus einem Bohrloch zu entfernenden Gegenstand angepasst sind, mit Mitteln (78, 85), welche auf einem der rohrförmigen Elementen (2, 3) angeordnet sind und eine Kammer (83) zwischen den rohrförmigen Elemente (2, 3) begrenzen, mit einer Kolbeneinrichtung (89), welche die Kammer (83) verschliesst und treibend mit einem der rohrförmigen Elemente (3) zur Bewegung durch dasselbe verbunden ist, mit einem im wesentlichen nicht komprimierbaren hydraulischen Fluidum, welcher in die Kammer (83) eingefüllt ist und sich der Relativvbewegung der Kolbeneinrichtung (89) widersetzt, wobei die Kolbeneinrichtung (89) in eine Richtung bewegbar ist, um das Fluidum in der Kammer (83) unter Druck zu setzen durch die Relativbewegung zwischen den rohrförmigen Elementen (2, 3) in einer Richtung, wobei eines der rohrförmigen Elemente (2, 3) eine Ventilöffnung (82) hat, welche zwischen der Kolbeneinrichtung (89) und dem Ende der Kammer angeordnet ist, eine Ventileinrichtung (84), welche anfangs die Ventilöffnung (82) verschliesst und bewegbar ist, um dieselbe zu öffnen und das Fluidum aus der Kammer (83) nach einer ersten vorgegebenen Relativbewegung der Kolbeneinrichtung (89) in der einen Richtung freizugeben und dadurch den Widerstand gegen eine weitere Relativbewegung der Kolbeneinrichtung (89) und der damit verbundenen Bewegung der rohrförmigen Element (2, 3) zur verringern, Durchgangsmittel (103), welche einen relativ geringen Durchfluss des Fluidums von der Kammer (83) während der ersten vorgegebenen Relativbewegung der Kolbeneinrichtung (89) erlaubt, und eine Hammer- (70) und Amboss-(65) einrichtung, welche von einem Schlagscherenstoss nach der weiteren Relativbewegung der rohrförmigen Element (2, 3) getroffen wird, gekennzeichnet durch eine feste Stoppeinrichtung (120), auf einem der rohrförmigen Elemente (2, 3), welche nach der ersten vorgegebenen Relativbewegung der Kolbeneinrichtung (86) in der einem Richtung treibend mit der Ventileinrichtung (84) zum Eingriff kommt.

2. Schlagschere nach Anspruch 1, in welcher die Hammer- und Ambosseinrichtung ein Hammerteil auf einem rohrförmigen Element und ein Ambossteil auf dem anderen rohrförmigen Element umfasst, die durch eine Schlagkraft in einer Richtung nach einer zweiten vorgegebenen Relativbewegung der rohrförmigen Elemente in der einen Richtung zum Eingriff kommen.

3. Schlagschere nach Anspruch 1 oder 2, in welcher die Durchgangseinrichtung, welche den Fluidumfluss erlaubt, mindestens einen Durchgang umfasst, welcher der Kolbeneinrichtung zugeordnet ist, und während der ersten vorgegebenen Relativbewegung der rohrförmigen Teile funktioniert, um das Fluidum aus der Kammer freizusetzen.

4. Schlagschere nach Anspruch 3, in welcher der den Fluidumdurchfluss zulassende Durchgang in der Kolbeinrichtung angeordnet ist.

5. Schlagschere nach einem der Ansprüche 1 bis 4, in welcher die Ventileinrichtung einem auf einem der rohrförmigen Elemente getragenden Ventilteil umfasst, welcher die Ventilöffnung verschliesst, sowie ein elastisches Mittel, welches mit dem Ventilteil zusammenwirkt, um dieses in die anfangs gschlossene Stellung zu drängen.

6. Schlagschere nach einem der Ansprüche 1 bis 5, in welcher die rohrförmigen Elemente einen inneren rohrförmigen Dorn und ein äusseres rohrförmige Gehäuse sind.

7. Schlagschere nach Anspruch 6, in welcher der innere rohrförmige Dorn mehrere in gleichem Abstand angeordnete und sich in Längsrichtung auf seiner Aussenfläche erstreckende Keile und Nutel aufweist, das äussere rohrförmige Gehäuse mehrere in gleichem Abstand angeordnete sich in Längsrichtung auf seiner Innenfläche erstreckende Keile und Nuten hat, wobei die Keile auf jedem rohrförmigen Element von solcher Grösse und Form sind, dass sie in die Nuten des anderen rohrförmigen Elementes hineinpassen und die Keile und Nuten die Längsbewegung der rohrförmigen Elemente ermöglichen, während sie die relative Drehbewegung zwischen ihnen verhindern.

8. Schlagschare nach Anspruch 7, in welcher der Hammerteil mehere in gleichem Abstand angeordnete Keile und Nuten hat, welche in die Keile und Nuten des äusseren rohrförmigen Elementes hineinpassen, in Hinblick auf die darin stattfindende Längsbewegung.

9. Schlagschere nach Anspruch 6, in welcher die Ventilöffnung sich in dem inneren rohrförmigen Dorn befindet und das Ventilteil den inneren rohrförmigen Dorn umgibt und darauf gleiten kann, um die Ventilöffnung für die Freilassung des Fluidums aus der Kammer zu steuern, wobei das Ventilteil mit dem inneren rohrförmigen Dorn bewegbar ist, wenn dieser sich relativ zum äusseren rohrförmigen Gehäuse bewegt.

10. Schlagschere nach Anspruch 9, in welcher die rohrförmigen Elemente eine zweite Kammer (64; 108) umschliessen, welche mit der zuerst genannten Kammer über die Ventilöffnung (82) in Verbindung steht und die Öffnungsbewegung der Ventileinrichtung (84) funktioniert, um das Fluidum freizugeben, um aus der erstgenannten Kammer (83) in die zweite Kammer (108) zu fliessen.

11. Schlagschere nach einem der Ansprüche 6 bis 10, in welcher das äussere rohrförmige Gehäuse eine feststebende Stoppeinrichtung hat.

12. Schlagschere nach Anspruch 10, welche Dichtungsmittel (111) umfasst, die mit den rohrförmigen Teilen zusammenwirken, um die zweite Kammer dazwischen zu begrenzen und in welcher die Kammerbegrenzungsmittel (78, 85) Mittel haben, um die Kolbeneinrichtung (89) durch die Relativbewegung der rohrförmigen Elemente in einer Richtung zu bewegen.

13. Schlagschere nach Anspruch 12, mit einem Durchgang (108), welcher sich von einem Endteil (64) zu dem anderen Endteil (108) der zweiten Kammer um die erstgenannte Kammer (83) herum erstreckt (77), damit das Fluidum dazwischen fliessen kann.

14. Schlagschere nach Anspruch 9, in welcher die Kolbeneinrichtung ein ringförmiges Kolbenelement hat, welches den inneren rohrförmigen Dorn umgbit und in das äussere rohrförmige Gehäuse hineinpasst, wobei das Kolbenelement relativ zu jedem der rohrförmigen Elemente verschiebbar ist, die Ventileinrichtung ein Ventilelement, welches wenigstens zum Teil durch den Fluidumdruck in der Kammer in der Schliesstellung gehalten wird, umfasst, sowie eine Federeinrichtung, welche mit dem Ventilelement zusammenwirkt, um dieses in die geschlossene Stellung zu drängen.

15. Schlagschere nach Anspruch 12, in welcher eine weitere Dichtung (92) eine Dichtung zwischen den rohrförmigen Elementen an einem Ende der Kammer umfasst, wodurch eine Gleitbewegung in Längsrichtung möglich ist, der innere rohrförmige Dorn eine vom Kolbenelement berührbare Schulter hat, um diesen in Richtung der Dichtung durch die Relativbewegung der rohrförmigen Elemente in einer Richtung zu bewegun und einen toten Gang zwischen dem inneren rohrförmigen Dorn und dem Ventilelement bereitzustellen.

Revendications

1. Coulisse de repêchage hydraulique comprenant une paire d'éléments tubulaires (2, 3) placés l'un dans l'autre de sorte à pouvoir exécuter un mouvement longitudinal limité l'un par rapport à l'autre et adaptés pour connecter l'un des éléments tubulaires (2) à une tige de forage et l'autre élément tubulaire (3) à un object à sortir d'un puits, des moyens (78, 85) disposés sur l'un des éléments tubulaires (2, 3) et définissant une chambre (83) entre les éléments tubulaires (2, 3), un moyen de piston (89) fermant ladite chambre (83) et connecté de façon active à l'un des éléments tubulaires (3) pour être déplacé par celui-ci, un fluide hydraulique substantiellement non compressible étant versé dans ladite chambre (83) et résistant au mouvement relatif du moyen piston (89), ledit moyen de piston (89) pouvant se déplacer dans une direction pour appliquer une pression au fluide dans ladite chambre (83) suite à un mouvement relatif entre lesdits éléments tubulaires (2, 3) dans une direction, un des éléments tubulaires (2, 3) comprenant une ouverture de soupape (82) placé entre ledit moyen piston (89) et l'extrémité de ladite chambre, un moyen de soupape (84) fermant initialement ladite ouverture de soupape (82) et pouvant se déplacer pour l'ouvrir pour libérer le fluide de ladite chambre (83) suite à un premier mouvement relatif prédéterminé dudit moyen piston (89) dans ladite direction et réduire ainsi substantiallement la résistance au mouvement relatif supplémentaire dudit moyen de piston (89) et donc le mouvement desdits éléments tubulaires (2, 3), un moyen de passage (103) permettant un flux relativement menu de ladite chambre (83) pendant ledit premier mouvement relatif prédéterminé du moyen de piston (89), et un moyen de marteau (60) et d'enclume (65) pouvant être soumis à un impact de coulisse suite au mouvement relatif supplémentaire desdits éléments tubulaires (2, 3), caractérisée par un moyen d'arrêt fixe (120) sur un desdits éléments tubulaires (2, 3) pouvant être contacté de façon active par ledit moyen de soupape (84) suite audit premier mouvement relatif prédéterminé du moyen de piston (89) dans ladite direction.

2. Coulisse selon la revendication 1, dans laquelle ledit moyen de marteau et d'enclume comprend un élément de marteau sur un élément tubulaire et un élément d'enclume sur l'autre élément tubulaire pouvant être soumis à une force d'impact dans une direction après un second mouvement relatif prédéterminé desdits éléments tubulaires dans ladite direction.

3. Coulisse selon la revendication 1 ou 2, dans laquelle ledit moyen de passage permettant le flux de fluide comprend au moins un passage associé audit moyen de piston et fonctionnant pendant ledit premier mouvement relatif prédéterminé desdits éléments tubulaires pour libérer le fluide de ladite chambre.

4. Coulisse selon la revendication 3, dans laquelle ledit passage permettant le flux de fluide se trouve dans le moyen de piston.

5. Coulisse selon l'une quelconque des revendications 1 à 4, dans laquelle ledit moyen de soupape comprend un élément de soupape porté sur un desdits éléments tubulaires et fermant ledit ouverture de soupape et un moyen élastique coopérant avec ledit moyen de soupape pour le forcer dans sa position initialement fermée.

6. Coulisse selon l'une quelconque des revendications 1 à 5, dans laquelle lesdits éléments tubulaires sont un mandrin tubulaire intérieur et une enveloppe tubulaire extérieure.

7. Coulisse selon la revendication 6, dans laquelle ledit mandrin tubulaire intérieur comprend une pluralité de cannelures et rainures équidistantes s'étendant et direction longitudinale sur la surface extérieure du mandrin, ladite enveloppe tubulaire extérieure comprend une pluralité de cannelures et rainures équidistantes s'étendant en direction longitudinale sur la surface intérieure de l'enveloppe, les cannelures sur chaque élément tubulaire étant d'une grandeur et forme s'insérant dans les rainures sur l'autre élément tubulaire, et les cannelures et rainuires fonctionnant pour permettre le mouvement longitudinal des éléments tubulaires tout en évitant un mouvement de rotation relative entre eux.

8. Coulisse selon la revendication 7, dans laquelle l'élément marteau comprend une pluralité de cannelures et rainures équidistantes s'insérant dans les cannelures et rainures de l'élément tubulaire extérieur pour pouvoir exécuter un mouvement longitudinal dans celui-ci.

9. Coulisse selon la revendication 6, dans laquelle ladite ouverture de soupape se trouve dans le mandrin tubulaire intérieur et ledit élément de soupape entoure ledit mandrin tubulaire intérieur et peut glisser sur celui-ci pour contrôler l'ouverture de soupape pour libérer le fluide de ladite chambre, ledit moyen de soupape se déplaçant avec ledit mandrin tubulaire intérieur suite à un mouvement de celui-ci par rapport à l'enveloppe tubulaire extérieure.

10. Coulisse selon la revendication 9, dans laquelle lesdits éléments tubulaires entourent une second chambre (60; 108) communiquant avec la chambre nommée en premier lieu par ledit moyen de soupape (82), et dans laquelle le mouvement d'ouverture du moyen de soupape fonctionne pour libérer le fluide de ladite chambre (83) nommée en premier lieu vers ladite seconde chambre (108).

11. Coulisse selon l'une quelconque des revendications 6 à 10, dans laquelle l'enveloppe tubulaire extérieure comprend un moyen d'arrêt fixe.

12. Coulisse selon la revendication 10, comprenant un moyen d'étanchéité (111) coopérant avec lesdits éléments tubulaires pour définir ladite seconde chambre entre eux et dans laquelle les moyens (78, 85) définissant la chambre comprennent un moyen pour déplacer le moyen de piston (89) en réponse au mouvement relatif desdits éléments tubulaires dans une direction.

13. Coulisse selon la revendication 12, comprenant un passage s'étendant (77) d'une partie extrême (64) vers l'autre partie extrême (108) de ladite seconde chambre autour de la chambre (83) nommée en premier lieu pour permettre le flux de fluide entre elles.

14. Coulisse selon la revendication 9, dans laquelle ledit moyen piston comprend un élément de piston annulaire entourant ledit mandrin tubulaire intérieur et s'insérant ladite enveloppe tubulaire extérieure, ledit élément de piston étant mobile par rapport à chacun desdits éléments tubulaires, ledit moyens de soupape comprenant un élément de soupape maintenu en position fermée au moins en partie par la pression de fluide dans ladite chambre et des moyens de ressort coopérant avec ledit élément de soupape pour le forcer dans la même position fermée.

15. Coulisse selon la revendication 12, dans laquelle un joint (92) supplémentaire comprend un joint entre lesdits éléments tubulaires à une extrémité de ladite chambre permettant le mouvement glissant longitudinal, ledit mandrin tubulaire intérieur a une épaule pouvant être contactée par ledit élément de piston pour la déplacer vers ledit joint en réponse au mouvement relatif desdits éléments tubulaires dans une direction et fournissant une course morte entre le mandrin tubulaire intérieur et ledit moyen de soupape.

Drawing