US3004616A

US3004616A - Jar

Info

Publication number: US3004616A
Application number: US612489A
Authority: US
Inventors: Benjamin P Nutter; Hugh E Metcalf
Original assignee: Johnston Testers Inc
Current assignee: Johnston Testers Inc
Priority date: 1956-09-27
Filing date: 1956-09-27
Publication date: 1961-10-17
Anticipated expiration: 1978-10-17

Description

Oct. 17, 1961 Filed Sept. 27, 1956 B. P. NUTTER ETAL JAR rfn/ U 2 Sheets-Sheet 1 ,cla-2 www :xfa

2 sheets-sheet 2 B. P. NUTTER ET AL JAR Oct. 17, 1961 Filed sept. 27, 195e United States Patent() 3,004,616 JAR 'Ihis invention relates to well jars and, more specifically, to well jars of the hydraulic type yfor use with oil well testing equipment.

In carrying on oil well testing procedures, various testing tools and one or more packers are connected to a pipe string and lowered into a well bore. The packers are set to seal off the well bore and standard testing procedures are followed, using the testing tools. At the end of the test, the packers are released and the pipe string is removed from the well. Sometimes, however, the packer or tools below it may become stuck in the well. To 'overcome this problem, a jar is often connected in the pipe string above the upper packer where it may be operated to free the stuck object so that the pipe string may be removed. If a jar is not placed inthe pipe string, there is the danger that the pipe string may be broken in attempting to remove it by a manipulation of the pipe string alone. Thus, a pipe string may often be Ifreed by repeated impacts of a jar, although stuck too tight to be freed by straight tensioning.

From the foregoing, it would appear that it would always be advisable to insert a jar in the pipe string in the eventuality that testing equipment becomes stuck in the well bore, but in practical usage this is not always done. The jar is but one of many tools to be connected at theend of the pipe string, and the total length of the tools is an important practical consideration to be weighed in determining what elements are to be fused. Hence, the utilization of many existing jars is restricted because of their over-all length.

Therefore, it is an object of this invention to provide a new and improved jar having a minimum overall length and, hence, `a greater utility in well testing operations.

It is a further object of this invention to provide a new and improved hydraulic jar utilizing iixed packing retainers for the hydraulic fluid chambers and having rotation prevention splines arranged to require no extension of the overall length.

It is a further object of this invention to provide a new and improved hydraulic jar of economical and rugged construction adapted to be readily maintained.

In accordance with the present invention, a well jar is provided which includes a mandrel and an annular housing together defining a uid chamber through which the mandrel extends. The housing has a grooved and an ungrooved bore portion of like diameter dening the outer wall of the chamber. A valve member carried by the mandrel moves from within the ungrooved position to within thev grooved portion providing first for a restricted flow of iiuid, then for a rapid ow as the jar is extended. An anvil is also carried by the mandrel and has longitudinally extending splines thereabout which are retained in the grooved portion to lock said mandrel and housing against relative rotation. `An' impact face on the mandrel strikes an impact face on the housing to terminate extension of the jar and to impart a iarringblow to an object connected by Vthe jar to the lower end of a drill string.

Other objects Vand advantages will become apparent in the following detailed description.

In lthe accompanying drawings, lforming a part of this application, and in which like numerals are used to designate like parts throughout the same,

FIG. l is a sectional elevational view of a jar embodying the invention;

FIGS. 2 and 3 are sectional elevational views of the upper and lower parts, respectively, of the jar of FIG. l on an enlarged scale, showing the jar in collapsed position;

FIG. 4 is a partial sectional elevational view similar to FIGS. 2 and 3, showing the jar in extended position;

FIG. 5 is a cross-sectional view of the jar taken on line 5-5 of FIG. 2; and

FIG. 6 is a cross sectional view of the jar taken on line 6-6 of FIG. 4. v

In the drawings, there is shown for the purpose of illustrating a preferred embodiment of the invention, a jar which comprises an annular housing member v11 having aniupper section 12, a middlesection 13, and a hammer sub 14, each being threadedly connected to the adjacent section. The Aupper housing section 12 is provided Ywith internal threads 16 adapted to receive the lower end of a pipe string 17.

A mandrel 18, having an upper wash mandrel section 19, an intermediate section 21, and a lower section 22, is internally and concentrically received within the housing member 11 yfor limited longitudinal movement as a unit with respect to the housing member. The bottom end of the mandrel 18 is provided with external threads 23 adapted to be connected to conventional testing equipment 24. A central bore `25 provides a uid passage lengthwise through mandrel 18.

The housing section 13 has upper and

lower portions

26 and 27 of unequal length but with `equal internal diameters, these portions forming, with the mandrel 18, a hydraulic fluid chamber 28. The chamber 28 is sealed at the top by a packing member 29 iixed by means of an annular external ilange 31 to the housing member 11 by the screw connection of housing sections 12 and 13.

An O-ring 32 seals against fluid flow from the chamber 28 past the outer surf-ace of packing member 29, and O-

rings

33 and 34 prevent Huid flow between the mandrel 18 and the packing member 29. The lower end of chamber 28 is sealed by means of 0rings '36, 37 and 38 which prevent tluid ow between the hammer sub. 114 of housing member 11 and mandrel 18. The mandrel 18 has'the same external diameter at the upper sealing member 29 and at

lower sealing rings

36, 37 and 38, and thus the chamber volume is maintained constant regardless of the relative longitudinal positions of the mandrel and the housing member. A plug 39 allows the chamber 28 to be lled with a suitable hydraulic Huid. Y v

Surrounding the intermediate mandrel section 21 is an annular valve member 41 having an external diameter slightly less than the internal diameter of the lrelatively short upper portion 26 of the middle housing section 13 to allow a restricted vlow of fluid between thevalve member 41 and the portion 26. The valve member 41, as seen in FIGS. 2 and `6, has an internal diameter substantially greater than the outerdiameter of the corresponding portion of mandrel section 21 and is centered for sliding movement along the mandrel section by cireumferentially spaced longitudinal splines 42 formed on said mandrel section, such splines having cylindrical outer surfacesv slidably ttted Within valve member 41. An outwardly extending annular valve seat 43 is formed on the mandrel section 21 to limit the upward movement of valve member 41 and to shut olf lluid llow through grooves 45 formed in eircumferentially spaced relation between the splines 42 when the valve member 41 is forced against the valve seat 43. An annular valve stop 44 surrounds the mandrel section 21 below the valve member 41 and limits downward movement of the valve member to a travel sutiicient to open the valve. The internal diameter of the valve stop member 44 corre- Y n a spends to the internaldiameter of the valve member 41, and lateral bores 46 formed through the valve stop member allow iluid communication from the chamber 28 tothe grooves 45 between the valve member 41 and mandrel section 21 when the valve memberrests against the valve stop member 44. Y

The mandrel section 22 is radially enlarged at its upper end to form Van anvil 46a having an annular downwardly facing impact face 47. Longitudinal splines 48 are formed on the external surface of anvil 46a,`extend ing short of the impact face 47, and mating 4with grooves 49 formed longitudinally of the inner surface ofJthe relatively long lower portion 27 ofthe section 13. These splines and grooves prevent relative rotation'between the mandrel 18 and housing member 11, while permitting limited relative longitudinal movement therebetween. As will be seen in FIG. 5, the housing portion 27 has a greater number of grooves 49 than the anvil V46a has splines and thus there is relatively free fluid communica-V tion'from one side of anvil 46a to the other in chamber 28 through the unoccupied grooves 49.

The hammer sub 14 of housing member 11 has an upwardly directed impact face 52 adapted to contact the anvil impact face 47 when the jar 10 is pulled into itsl extended position. n

The jar is assembled as in FIG. 1 with the chamber 4 allow for thelength of the iluid chamber 28 and the extendible length of the mandrel 18 with respect to the housing member 11.

The provision that the mandrel splines 48 terminate Short of the anvil impact face'47 insures that no impact will be delivered to the splines 48 upon the sudden extension of the jar, and thus eliminates the possibility that the relatively thin splines will'be sheared from the anvil upon impact. I

It is to be understood that the form of the invention, herewith shown and described, is to be taken as a preferredY embodiment ofthe same, and that various changes in the shape, size and arrangement of parts may be re# 28 being filled with hydraulic uid, and is connected to the lower end of a pipe string 17 and to the upper end of a packer element 24 of a conventional tester. If at the end of a test the packer, or any ofthe other testing elements, is stuck in the well bore, the stuck object may be jarred loose in the following manner. A steady stress is applied to the upper end of the well string, thus urging the housing member 11 upwardly while the mandrelV 18, being connected to the stuck object, remains stationary, As Ithehousing portion `26 moves upwardly with respect to valve member 41, the valve member is urged against the valve seat 43 and the uid in the lower portion of chamber 28 is subjected to pressure.v Since the fluid is essentially non-compressible, no relative movement results between thelhousing member 11 and mandrel 18 except -that provided by the transfer of fluid from the lower to the upper side of the valve member through the re# stricted passage between the valve member and housing portion 26. A- certain length of time is required Vfor the valve member 41 to move out of the housing portion 26, and during this timethe upward pull on the pipel string imparts a stretch to the pipe string. At the instant the valve member 41 clears the housing portion 26, a relatively free passage is providedfor the compressed fluid vin the lower section ofnchamber 28 `around the valve member 41 and the stretched pipe contracts upwardly, causing the housing member 11 to suddenly rise with respect to the mandrel to the. extended position shown in FIG. 4. The hammersub-impact face 52 strikes the anvil pact face 47, thus imparting a violent blow to the mandrel 18 and the stuckrobject to whichitis connected.

If this one lblow. is insuicient todislodgethe stuck object, the housing member 11 is again lowered. The valve member 41 moves downwardly against the valve stop member, thus providing a relatively unobstructed flow path to the fluid in the upper end of chamberl 28 to the lower end of that chamber.. With the jar 10 again in a collapsed position, another upward blow may beimparted to the stuck object as discussed previously. Success'ive blows may be generated until the stuck object becomes dislodged.

It will be noted that the'overall length of the jar 1t) is kept to a minimum by 'using a xed packing member 29 instead of a floating packing retainer, the latter Arequiring an additional length of housing in which to float, an'd by the disposition ofl'the mandrel'splines 48 and housing member grooves 49.c'o1`npletely within the lower portion of the fluid Acharr'iber 28. By this arrangement, the overall length of the jar 10 need be only enough to sorted to, without departing from the spirit of the invention, or the scope of the attached claims.

l. A well jar comprising an annular housing member and a cylindrical mandrel concentrically carried therein, said housing member and said mandrel being intertted for limited longitudinal movement relative to each other between a contracted position andan extended position, said housing member and said mandrel providing opposite ends for said jar adapted for connection in a pipe string above an object which may becomestuck in a well bore, annular seal means` of like diameter spaced longitudinally apart for effecting a sliding seal between saidvhousing member and mandrel to denean annular closed fluid-iilled chamber therebetween with said mandrel extending completely through said closed chamber, saidrhousing member having grooved and ungrooved portions of equal internaldiameter forming the outer wall of said chamber, an enlarged portion of said mandrel intermediate the ends of said chamber having a valve seat thereon, a valve memberrcarried by said mandrel and movable between a closed and an open position with respect to said seat by Huid pressure as said mandrel is extended and contracted, respectively, said valve member cooperating with the ungrooved portion of said outer chamber wall to restrict iluid flow. past said enlarged .portion in its closed position Yand to enhance -uid flow therepast in its open position, and an annular anvil carried by said mandrel` slidably within said grooved portion of said outer chamber wall and closed to uid flow therethrough, said grooved portion of said outer chamber wall providing unrestricted fluid flow around said anvil and around said enlarged portionwhen said jar is proximate `to its extended position, said anvil and said housing meinber Ahaving confronting impact faces adapted to contact when said mandrel and housing member move to said extended position, said anvil having at least one spline engaged in said grooved portion of said outer chamber wall to prevent rotation between said mandrel and said housing member. A

2. A well jar comprising an annular housing member and a mandrelconcentrically carried therein, said housing member and said mandrel being interitted for limited longitudinal movement relative to each other between a contracted positionhand an extended position, said housing member and saidmandrelproviding opposite `ends for. said jar adapted for connection in a pipe string above an object which may become stuck in a well bore, seal means of like diameterspaced longitudinally apart for effecting a sliding seal between said housing member and lmandrel to define an annular closed uidchamber therebetween with said mandrel extending completely through said closed chamber, ,said housing member having grooved and ungrooved portions ofequal internal diameter forming the outer wall-of the chamber, an en*- larged portion of said mandrel intermediate the ends of said chamber providing a valve seat, a valve member movable ybetween a closed andan open position with respect to said seat by fluid pressure `as said mandrel is.

Y lextended and contracted, said valve member cooperating its closed position and to enhance fluid flow therepast in its open position, said groove portion of said outer charm ber walll providing unrestricted fluid flow around said enlarged portion and valve member when said jar is proximate to its extended position, and an anvil carried by said mandrel and disposed within said grooved portion, said anvil and said housing member having confronting impact faces adapted to contact when said mandrel and housing member move to said extended position, said anvil having at least one spline for engaging said grooved portion to prevent rotation between said mandrel and said housing member, each such anvil spline terminating short of said anvil impact face and being retained in said grooved portion. t

3. A well jar comprising an annular housing member and a sectional tubular, mandrel concentrically carried therein, said housingmember and said mandrel being interfitted 4for limited longitudinal movement relative to each other between a contracted position andan extended position, said housing member and said mandrel providing opposite ends for said jar adapted for connection in a pipe string above an object which may become stuck in a well bore, seal means of like diameter spaced longitudinally apart for effecting a sliding seal between said housing member and mandrel to define an annular closed fluid-filled chamber therebetween with said mandrel extending completely through said closed chamber, said housing member having grooved and ungrooved portions of equal internal diameter forming the outer wall of said chamber, an enlarged portion of one section of said mandrel intermediate the ends of said chamber having a valve seat thereon, a valve member carried by said mandrel and movable between a closed and an open position with respect to said seat by fluid pressure as said mandrel is extended and contracted, respectively, said valve member cooperating with the ungrooved portion of said outer chamber wall to restrict fluid flow past said enlarged portion in its closed position and to enhance fluid flow therepast in its open position, and an annular anvil integrally carried by a second section of said mandrel slidably within said grooved portion of said outer chamber wall and closed to fluid flow therethrough, said `grooved portion of said outer chamber'wall providing unrestricted fluid flow around said anvil and around said enlarged portion when said jar is proximate to its extended position, said anvil and said housing member having confronting impact faces adapted to contact when said mandrel and housing member move to said extended position, said anvil having at least one spline engaged in said grooved portion of said outer chamber wall to prevent rotation between said mandrel and said housing member, said ungrooved portion of said housing member being substantially shorter than said grooved portion, said anvil threadedly receiving an end of said one mandrel section to connect said second section therewith, and said enlarged portion and said valve member being completely received within said ungrooved portion when said jar is fully contracted.

4. A well jar comprising an annular housing member and a mandrel concentrically carried therein, said housing member and said mandrel being interfitted for limited longitudinal movement relative to each other between a contracted position and an extended position, said housing member and said mandrel providing opposite ends for said jar adapted for connection in a pipe string above an object which may become stuck in a well bore, seal means spaced longitudinally apart for effecting a sliding seal between said housing member and mandrel to define an annular closed fluid chamber therebetween with said mandrel extending completely through said closed cham'ber, said seal means having a fixed longitudinal spacing and the same effective diameter, said housing member having grooved and ungrooved portions of equal internal diameter forming the outer wall of the chamber, an enlarged portion of said mandrel intermediate the ends of said chamber providing a valve seat of annular configuration carried by said mandrel, a valve member of annular configuration slidable a limited longitudinal distance along said mandrel between a 'closed and an open position with respect to said seat by fluid pressure as said mandrel is-extended and contracted, said valve seat sealing with said valve member when said mandrel and housing member are being extended, said valve member cooperating with the ungrooved portion of said outer uid chamber wall to restrict fluid flow past said enlarged portion in its closed position and to enhance fluid flow therepast in its open position, said grooved portion of said outer chamber wall providing unrestricted fluid flow around said enlarged portion and valve member when said jar is proximate to its extended position, and an anvil carried by said mandrel and disposed within said grooved portion, said anvil and said housing member having confronting impact faces adapted to contact when said mandrel and housing member move to said extended position, said anvil having at least one spline for engaging said grooved portion to prevent rotation between said mandrel and said housing member.

5. A well jar comprising an annular housing member and a mandrel concentrically carried therein, said housing member and said mandrel being inteltted for limited longitudinal movement relative to each other between a contracted position and an extended position, said housing member and said mandrel providing opposite ends for said jar adapted for connection in a pipe string above an object which may become stuck in a well bore, seal means spaced longitudinally apart for effecting a sliding seal between said housing member and mandrel to define an annular closed fluid chamber therebetween with said mandrel extending completely through said closed chamber, said seal means having a fixed longitudinal spacing and the same effective diameter, said housing member having grooved and ungrooved portions of equal internal diameter forming the outer wall of the chamber, an enlarged portion of said mandrel intermediate the end of said chamber providing a valve seat of annular configuration carried by said mandrel, a valve member of annular configuration slidable a limited longitudinal distance along said mandrel between a closed and an open position with respect to said seat by fluid pressure as said mandrel is extended and contracted, said valve seat sealing with said valve member when said mandrel and housing member are being extended, said valve member cooperating with the ungrooved portion of said outer fluid chamber wall to restrict fluid flow past said enlarged portion in its closed position and to enhance fluid flow therepast in its open position, said grooved portion of said outer chamber wall providing unrestricted fluid flow around said enlarged portion and said Valve member when said jar is proximate to its extended position, and an anvil carried by said mandrel and disposed within said grooved portion, said anvil and said housing member having confronting impact faces adapted to contact when said mandrel and housing member move to said extended position, said anvil having at least one spline for engaging said grooved portion to prevent rotation between said mandrel and said housing member, an annular apertured stop member disposed around said mandrel intermed-iate said val-ve member and said anvil, said mandrel being relieved to provide a passage extending beneath said valve member and terminating interiorly of said stop member for the flow of fluid therethrough when said jar is being contracted.

6. A Well jar comprising an annular housing member and a mandrel concentrically carried therein, said housing member and said mandrel being interfitted for limited longitudinal movement relative to each other between a contracted posit-ion and an extended position, means adapted to connect one end of the housing member -to a pipe string, means adapted to connect the opposite end of the mandrel to an object which may become -stuc'kIin a well bore, sealmeans of like diameter spaced longitudinally vapart for effecting a sliding seal between saidj housing member and mandrel to deline an annular closed fluid chamber therebetween with `said mandrel extending completely through said closed chamber, said housing member having adjacent grooved and ungrooved portions extending longitudinally of the chamber, an annular valve member surrounding said mandrel and adapted to be received in the ungrooved portion of said housing member when the well jar is in its contracted position, the outer diameter of said valve member'being slightly smaller than the diameter of said ungrooved portion to'permit restricted iluid flow between the valve member and said ungrooved portion, said valvevr member having an inner bore cooperating with the underlying portion of said mandrel to dene a passage extending lengthwise beneath said valve member, a valve seat of annular coniiguration on an Yenlarged portion of said mandrel intermediate the ends of said chamber, said valve member being adapted to seat on said valve seat, an annular Valve stop member surrounding said mandrel and adapted to allow said valve to move a limited distance from said valve mem,- ber seat passage means in said valve stop member allowing uid communication from the passage provided between said mandrel and said =valve member-to the outer surface of said valve stop member, said valve membersbeing adapted to tbe completely received 4in the grooved portion of said housing member when said jar is in extended position, an anvil having an impact face carried, by said mandreljand disposed within said grooved housing portion, said anvil serving to position said valve stop member with respect to said mandrel, said housing member having an impact face defining the lower end of said chamber and adapted to contact the impact face of said anvil when said mandrel and housing member move to said extended position, and a plurality of splines formed longitudinally of said anvil and received in said grooved housing portion lto prevent relative rotation between said mandrel andY said housing member, said grooved portion affording a longitudinal passage for the passage of fluid around said anvil and said valve member.

7. A well jar comprising an annular housing member and a mandrel concentrically carried therein, said housing member and said mandrel being interfitted for lim- Y 8 ited longitudinal movement relativev to each other between a contracted position and an extended position, said housing Amember and said mandrel providing opposite ends for said jar adapted for connection in a well string above'l an object which may become stuck in a well bore, seal means of like diameter spaced longitudinally apart for effecting a sliding seal between said housing member and mandrel to define an annular closed fluid-filled chamber therebetween with said mandrel extending completely through said closed chamber, said housing member having grooved and ungrooved portions of equal internal diameter forming the outer wall of said chamber, an enlarged portionV of said mandrel intermediate the ends of said chamber having a valve seat thereon, a valve member carried by said mandrel and movable between a closedV and an open position with respect to said seat by fluid pressurel as said mandrel is extended Vand contracted, said valve member cooperating with Ithe ungrooved portion of said outer chamber wall to restrict uid ilow past said enlarged portion in its closed position and to enhance fluid ow therepast in its open position, and an annular anvil carried by said mandrel slidably within said grooved portion of said outer chamber wall, said grooved portion of said outer chamber wall providingunrestricted iluid iow around said anvil and around said enlarged portion when said jar is proximate to its extended position, said anvil and `said housing member having confronting impact faces adapted to contact when said mandrel and housing member move to saidextended position, said mandrel carrying at least onerspline engaged-in said grooved portion of said outer chamber -wall along a length of said wall which overlaps substantially with Ithe length thereof traversed by lsaid enlarged portion in movement of said mandrel from its contracted to itsextended position, thereby to prevent rotation between said mandrel and said housing member.

References Cited in the file .of this patent Osmun Dec. v 1, 1957