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Publication numberUS3349858 A
Publication typeGrant
Publication dateOct 31, 1967
Filing dateOct 14, 1965
Priority dateOct 14, 1965
Publication numberUS 3349858 A, US 3349858A, US-A-3349858, US3349858 A, US3349858A
InventorsChenoweth David V
Original AssigneeBaker Oil Tools Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydraulic jarring apparatus having a restricted flow path from its chamber with constant flow regulator means
US 3349858 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Oct. 31, 1967 HYDRAULIC JARRIN D V. CHENOWETH FLOW PATH FROM ITS CHAMBER WITH CONSTANT FLOW REGULATOR MEANS Filed Oct. 14, 1965 G APPARATUS HAVING A RESTRICTED 2 Sheets-Sheet 1 Dav/o .II. CHENOWETH IN VEN TOR.

ATTORNEY D.'V. CHENOW RING APPARA ROM ITS LOW REG Oct. 31, 1967 H 3,349,858

HYDRAULIC JAR TUS H NG A RESTRICTED FLOW PATH F CHAMBER WITH CONSTANT F ULATOR MEANS 2 Shegts-Sheet 2 Filed Oct. 14, 1965 United States Patent Ofiice 3,349,858 HYDRAULIC JARRING APPARATUS HAVING A RESTRICTED FLOW PATH FROM ITS CHAMBER WITH CONSTANT FLOW REGULATOR MEANS David V. Chenoweth, Houston, Tex., assignor to Baker Oil Tools, Inc., Commerce, Califl, a corporation of California Filed Oct. 14, 1965, Ser. No. 495,937 Claims. (Cl. 175-297) The present invention relates to subsurface well bore equipment, and more particularly to hydraulic jars used in well bores for delivering an impact blow for the purpose of freeing devices stuck in the well bore, or moving devices in the well bore.

In hydraulic jarring apparatus a stretch or pull is taken on a pipe or other running-in string attached to the jar assembly for the purpose of forcing a piston against oil, or other liquid, in the apparatus, causing it to flow through a narrow passage or passages until the piston moves into a larger diameter of the surrounding cylinder, whereupon the piston is freed and the stretch taken in the running-in string is eflfective to accelerate the assembly secured to the running-in string and cause a knocker or hammer portion thereto to strike a companion knocker or hammer portion on a surrounding body, which is secured directly or indirectly to the device to be moved.

In the prior devices, extremely close tolerances have been necessary in connection with the piston and cylinder arrangement to control the flow of liquid, for the purpose of regulating the jarring action and the time over which the jarring cycle occurs. The time of the cycle varies with the strain taken on the pipe or running-in string.

In the present invention, a jarring apparatus is provided in which extremely close tolerances of the piston portion in the companion cylinder are not necessary, inasmuch as a suitable seal can be provided therebetween. The displacement of the liquid in the outer or cylindrical portion of the jarring mechanism from one side of the piston to the other occurs at a controlled rate, and without the requirement for having close tolerances between the portions of the apparatus. The strain taken on the inner or piston portion of the apparatus can vary and yet the time required for securing the impact blow will remain constant, since the liquid can only be displaced through the jarring mechanism at a controlled and constant rate. In view of the lack of necessity for providing close tolerances, the hydraulic jar apparatus is less costly to produce and is easier and more economical to maintain. Moreover, it is unnecessary to provide a confined body of oil as the liquid medium, since the liquid in the well bore itself can be used in the apparatus.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section, with parts shown in elevation, of a jarring mechanism or apparatus embodying the invention, with its parts in their initial or closed position prior to imparting a jarring blow;

FIG. 2 is a longitudinal section, on an enlarged scale, through the cylinder and piston portion of the apparatus illustrated in FIG. 1;

FIG. 3 isan enlarged fragmentary longitudinal section 3,349,858 Patented Oct. 31, 1967 portion of the apparatus disthrough the flow regulator closed in FIGS. 1 and 2;

FIG. 4 is a view similar to FIG. 3 illustrating the flow regulator mechanism in another position;

FIG. 5 is an enlarged cross-section taken along the line 5-5 on FIG. 1;

FIG. 6 is a cross-section taken along the line 6-6 on FIG. 2;

FIG. 7 is an enlarged section taken along the line 7-7 on FIG. 3.

A hydraulic rotary jar apparatus A is illustrated in the drawings, which is adapted to be lowered in a well bore on a suitable running-in string B, such as a string of pipe, and which is adapted to be suitably connected, in a known manner, to a fish (not shown) stuck in the well bore, or to some other device (not shown) in the well bore, upon which a jarring blow is to be imposed. As disclosed, the hydraulic jar apparatus includes a tubular inner member or mandrel 10 having an upper threaded box 11 for threaded attachment to the lower end of the tubular string B extending to the top of the well bore. This inner tubular member or mandrel is telescopically disposed within an outer tubular member or body 12, the lower end of which may have a suitable threaded pin 13 thereon for threaded attachment to a wash pipe (not shown), or any other mechanism, that is connected. by suitable means (not shown) to the fish or other device to be moved in the well bore.

The inner member or mandrel includes an upper section 14, having a threaded box 11, having a threaded pin 15 at its lower portion threadedly secured within a companion box 16 in the piston portion 117 of the mandrel which has a lower threaded box 18 for threaded attachment to a lower section 19 of the mandrel. The outer body 12 includes an upper section 20 that has internal splines 21 in its lower portion meshing with elongate external splines 22 of the mandrel, so that the mandrel 10 can be shifted longitudinally in the outer body 12 and yet allow full torque to be transmitted between the mandrel and the body in both rotary directions. The upper portion 23 of the upper body section 20 is in the form of a sleeve that has an internal seal ring 24 mounted thereon for slidably sealing against the cylindrical periphery 25 of the mandrel section 14 above its splined portion 22, the sealing engagement with the periphery being maintained during the entire length of stroke of the mandrel 10 within the outer body 12.

The upper section 20 of the outer body 12 is threaded ly secured to the main body section 26, which includes an intermediate portion 27 spaced from the splined portion 22 of the mandrel to form an elongate annular upper chamber 28 therebetween. Below the upper chamber portion 28, the outer body member has a cylindrical portion A 29 of a smaller internal diameter than the upper portion 27, providing a cylinder wall 30 along which the piston portion 17 of the inner mandrel can slide. The piston portion has anexternal diameter 31 substantially less than the internal diameter of the cylinder wall 30, providing an annular space 32 therebetween communicating at its upper end with the upper chamber 28. Despite the presence of this annular space, the piston is sealed against the cylinder wall by a piston or seal ring 33 mounted on the piston and slidably and sealingly engaging the cylinder wall. This seal ring may be of any suitable construction, its upper end bearing against a downwardly facing shoulder 34 on the piston and its lower end bearing against a retainer ring 35 slidable along the cylinder wall and held against the piston seal ring by a nut 36 threaded on the lower end of the piston 17.

A liquid disposed in the upper chamber 28 is adapted to move around the upper portion of the piston 17 and through the piston into a lower chamber 38 below the piston, defined between the lower section 19 of the inner mandrel and the cylindrical portion 29 of the outer body member 12. The lower end of this annular chamber 38 communicates with an annular space 39 between the lower mandrel section 19 and the inner reduced diameter wall 40 of the main portion 26 of the outer body, this lastmentioned annular space communicating with the interior of the mandrel section 19 through a plurality of circumferentially spaced, elongate, slotted ports 41 which are relatively narrow to function as a screen in connection with the passage of liquid from the wall bore into and out of the jar mechanism. This liquid is the restraining medium used in connection with the taking of a stretch on the pipe secured to the upper end of the hydraulic jar apparatus. The lower portion 42 of the lower mandrel section 19 below the thin, slotted ports 41 has a diameter conforming to the inside diameter of the body wall 40, to support the lower portion of the mandrel in its telescopic movement within the outer member or body 12.

The liquid in the upper chamber 28 can only pass to the lower chamber 38 by moving through a path that includes an annular space 32, which opens into a passage 43 within the piston controlled by a flow regulator valve 44. This flows regulator valve is disposed within a longitudinal bore 45 formed in the piston, the regulator valve including a cylinder 46 disposed in this bore and resting upon a shoulder 47 forming the lower end of the bore. The cylinder is maintained within the bore by an upper cylinder head 48 within the bore, whose substantial upward movement in the bore is prevented by the lower end 49 of the upper mandrel section 14 located closely adjacent thereto. Leakage of fluid around the periphery of the cylinder head is prevented by a suitable side seal ring 50 thereon sealingly engaging the wall of the bore.

Liquid can flow from the annular space 32 between the piston 17 and the cylinder wall 30 through a side port 51 in the piston opening into the bore 45. Such liquid will pass from the port 51 into a circumferential groove 52 in the cylinder 46, which communicates with a cylinder port 53 extending to its interior. A flow regulator sleeve or piston 54 is slidably mounted in the cylinder 46, having a peripheral groove 55 communicating with the cylinder port 53 and a side port 56 providing communication between this groove and the central passage 57 through the sleeve or piston valve. The lower end portion of the sleeve valve member has a central choke orifice 58 therein from which fluid can discharge into the longitudinal piston passage 43, extending from the enlarged bore or counterbore 45, for discharge from the lower end of the piston into the lower chamber '38. Leakage of fluid in a down- Ward direction along the cylinder sleeve 46 is prevented by a suitable side seal ring 59 thereon below its circumferential groove 52 engaging the wall of the piston bore 45 below the piston port 51.

The sleeve 54 is normally urged in an upward direction and into contact with the cylinder head 48 by a helical compression spring 60, the lower end of which bears against an upwardly facing piston shoulder 61, and the upper end of which engages the sleeve. When the sleeve is contacting the cylinder head 48, the groove 55 of the sleeve fully exposes the cylinder port 53 so that fluid can flow unrestrainedly through the cylinder port 53 and the sleeve port 56 to the interior of the latter. The flow of fluid through the regulator valve builds up a pressure diferential on the lower portion 62 of the sleeve across its orifice 58, which tends to shift the sleeve valve 54 downwardly against the force of the spring so as to shift the sleeve valve partially across the cylinder port 53 and throttle the area thereof.

The sleeve valve 54 with its orifice 58, and the spring 60 therebelow, will insure the maintenance of a predetermined pressure drop through the orifice, which is accompanied by a predetermined volumetric rate of flow of liquid therethrough. Thus, if the pressure on the upstream side of the orifice 58 tends to increase, the sleeve is shifted downwardly partially across the cylinder port 53 and reduces its area, thereby throttling the flow of fluid there through and decreasing the pressure on the upstream side of the orifice. On the other hand, should the pressure on the upstream side of the orifice tend to decrease, then the spring 60 moves the sleeve or piston 54 upwardly to increase the effective area of the cylinder port 53, thereby increasing the pressure of the liquid on the upstream side of the orifice. The sleeve, by its throttling action on the cylinder port, will maintain the pressure of the liquid flowing through the port 53 to the interior 57 of the sleeve valve, and on the upstream side of the orifice 58, at a substantially constant value, the flow of liquid through the orifice remaining at a substantially constant rate.

The presence of the constant flow regulator valve 44 insures that liquid can only transfer from the upper chamber 28 to the lower chamber 38 at a predetermined rate of flow, regardless of the upward strains taken on the pipe (not shown) connected to the inner mandrel 10 and its piston 17. With a lesser strain taken thereon, the effective flow area of the cylinder port 53 is greater, so that the throttling action or reduction of the pressure below that imposed upon the liquid in the upper chamber by the piston is less. On the other hand, if a much greater strain is taken on the pipe and the inner mandrel and its piston, the throttling action of the sleeve 54 will be greater, so that the higher pressure in the chamber 28 is reduced in value preparatory to passing into the central passage 57 of the sleeve valve member. Accordingly, the liquid pressure on the upstream side of the orifice 58 remains constant, insuring flow of fluid through the orifice at a constant rate.

In the use of the apparatus, it is first placed in the position illustrated in FIGS. 1 and 2, in which the inner mandrel 10 is fully telescoped within the body 12. The piston 17 can shift downwardly within the cylinder 29 very readily, since the liquid in the lower cylinderspace 38 can flow easily upwardly through a by-pass or return passage extending longitudinally through the piston to the upper chamber 28. Downward flow of liquid through this by-pass passage is prevented by a suitable check valve device 71, such as a ball valve member, that moves downwardly into engagement with a companion seat 72 in the passage. Upward movement of the ball member 71 away from its seat is limited by its engagement with the lower end 49 of the upper mandrel section. The ball member is disposed within an enlarged bore 73 of the by-pass passage 70 so that liquid can flow in an upward direction freely around the ball member and through the upper portion of the by-pass passage to the upper chamber.

Assuming the jarring apparatus has been lowered in the well bore and that it has been appropriately connected with the fish, or other device, in the well bore to be shifted, the mandrel 10 is moved downwardly within the body to the position disclosed in FIGS. 1 and 2, in which the piston seal 33 is in contact with the lower portion of the cylinder wall 30, the liquid in the well bore passing through the slotted ports 41 and the annular space 39 into the lower chamber 38 and then upwardly through the by-pass passage 70 and around the check valve 71 therein into the upper chamber 28 to fully fill the latter between the piston 17 and the head or hammer portion 20 of the outer body member 12. An upward strain or stretch is taken on the pipe B secured to the mandrel, the inner assembly of the jar being pulled upwardly at a rate which will always be constant since the liquid can only flow from the upper chamber 28 through the regulator valve 44 and the passage 43 at a constant rate. Such flow will occur with a stretch taken on the pipe, until the seal 33 moves out of the cylindrical bore 30 into the enlarged diameter portion 27 of the outer body member, which suddenly releases the resistance to upward movement of the pipe and piston, allowing unobstructed passage of fluid from the upper chamber 28 around the exterior of the piston 17. This results in continued upward movement of the entire inner assembly at an accelerated speed, due to the stretch on the pipe, until the upper hammer or knocker portion 80 at the upper end of the piston strikes the head or hammer portion 20 of the outer body member '12, the blow thus struck being transmitted through the outer body member, and through Whatever parts are connected to its lower portion, to the fish, or other device, in the Well bore that is to be freed or moved.

After a blow has been struck, the apparatus can be recocked for striking of another blow merely by lowering the pipe B and the inner mandrel to reshift the piston portion 17 downwardly within the cylinder, the liquid in the well bore and the lower chamber 38 moving relatively freely through the by-pass passage 70 and around the check valve 71 back into the upper chamber 28. Additional blows can be delivered as often as desired by repeating the foregoing cycle of operation. As indicated, regardless of the stretch taken upon the pipe and the force imposed on the pipe, the liquid can only be displaced from the upper chamber 28 and through the flow regulator valve 44 at a constant rate, insuring that the time of delivery of the blow, regardless of the degree of the blow, will be the same.

The apparatus need not be made with extremely close tolerances since the sealing effectiveness of the piston 17 with respect to the cylinder Wall 30 is readily obtainable through use of the piston seal ring structure 33. It is only essential that the flow regulator valve 44, and primarily the size of its orifice 58 and the force of its spring 60, be properly determined, to insure appropriate regulation of the jarring action and the time of each cycle. Inasmuch as close tolerances are unnecessary, the cost of producing the hydraulic jar apparatus is reduced, and it is easier to maintain in proper operating condition.

I claim:

1. In hydraulic jarring apparatus to be disposed in a well bore: an outer member having a hammer portion; an inner member disposed within and movable relative to said outer member, said inner member having a hammer portion; piston means on one of said members shiftable by relative movement between said members between a first position closely adjacent to the other of said members and a second position substantially spaced from said other of said members; said piston means when in said first position and with said hammer portions spaced from each other providing with said members a chamber on one side of said piston means adapted to contain a liquid; means providing a restricted flow path from said chamber for the liquid therein during movement of said piston means from said first position to said second position; flow regulator means in said restricted flow path for maintaining the rate of flow of liquid from said chamber substantially constant; liquid in said chamber being movable freely therefrom upon shifting of said piston means to said second position, whereby said hammer portions can impact upon each other.

2. In hydraulic jarring apparatus as defined in claim 1; said piston means being on said inner member.

3. In hydraulic jarring apparatus as defined in claim 1; said piston means being on said inner member; said restricted flow path means extending through said piston means; said flow regulator means being on said piston means.

4. In hydaulic jarring apparatus as defined in claim 1; said flow regulator means comprising an orifice, and automatically variable throttle means for maintaining substantially constant the pressure of the liquid on the upstream side of said orifice.

5. In hydraulic jarring apparatus as defined in claim 1; said flow regulator means comprising an inlet for the liquid in said chamber, a sleeve valve having an orifice and shiftable across said inlet to throttle the flow of liquid therethrough to the upstream side of said orifice.

6. In hydraulic jarring apparatus to be disposed in a well bore: an outer member having a hammer portion; an inner member telescopically disposed .in said outer member and having a hammer portion adapted to impact upon said other hammer portion; piston means on one of said members shiftable by relative longitudinal movement between said members between a first position closely adjacent to the other of said members and a second position substantially spaced from the other of said members; said piston means when in said first position with said hammer portions longitudinally spaced from each other providing with said members a chamber on one side of said piston means adapted to contain a liquid; means providing a restricted fiow path from said chamber for the liquid therein during longitudinal movement of said piston means from said first position to said second position; fiow regulator means in said restricted flow path for maintaining the rate of flow of liquid from said chamber substantially constant; liquid in said chamber being movable freely therefrom upon longitudinal shifting of said piston means to said second position, whereby said hammer portions can impact upon each other.

7. In hydraulic jarring apparatus as defined in claim 6; said piston means being on said inner member.

8. In hydraulic jarring apparatus as defined in claim 6; said piston means being on said inner member; said restricted flow path means extending through said piston means; said flow regulator means being on said piston means.

9. In hydraulic jarring apparatus as defined in claim 6; said flow regulator means comprising an orifice, and automatically variable throttle means for maintaining substantially constant the pressure of the liquid flowing from said chamber and within said flow path to the upstream side of said orifice.

10. In hydraulic jarring apparatus as: defined in claim 6; said flow regulator means having a liquid inlet for fluid from said chamber a sleeve valve having an orifice shiftable across said inlet to throttle the flow of liquid passing therethrough to the upstream side of said orifice.

11. In hydraulic jarring apparatus to be disposed in a well bore: an outer member having a hammer portion, a first cylindrical bore below said hammer portion, and a second cylindrical bore below said first cylindrical bore and of lesser diameter than said first cylindrical bore; an inner member telescopically disposed in said outer member and having a hammer portion below and adapted to impact upon said other hammer portion; a piston on said inner member in slidable sealing relation to the wall of said second bore; said inner and outer members providing a chamber above said piston for a liquid; means providing a restricted flow path from said chamber for the liquid therein during upward movement of said inner member and said piston within said outer member and with said piston in slidable sealed relation'to said second bore; flow regulator means in said restricted flow path for maintaining the rate of flow of liquid from said chamber substantially constant; liquid in said chamber being movable freely therefrom around the exterior of said piston upon shifting of said piston from sealed relation to said second bore, whereby said hammer portions can impact upon each other.

12. In hydraulic jarring apparatus as defined in claim 11; said flow regulator means comprising an orifice, and automatically variable throttle means for maintaining substantially constant the pressure of the liquid flowing from said chamber and into said flow path to the upstream side of said orifice.

13. In hydraulic jarring apparatus as defined in claim 11; said restricted flow path extending through said piston; said flow regulator means comprising an inlet for liquid from said chamber, a sleeve valve having an orifice and shiftable across said inlet to throttle the flow of liquid therethrough to the upstream side of said orifice.

14. In hydraulic jarring apparatus as defined in claim 11; means providing a by-pass for liquid from a region in said outer member below said piston to said chamber above said piston; and check valve means adapted to close said by-pass against downward flow of liquid therethrough. 15. In hydraulic jarring apparatus as defined in claim 11; passage means for liquid in the well bore into said outer member below said piston; means providing a bypass for the well bore liquid from below the piston to said chamber above said piston; and check valve means closing said by-pass against downward flow of liquid.

References Cited UNITED STATES PATENTS Sutlifi 175-297 Storm 175-297 Sutliff 175-297 Whittle 175-94 CHARLES E. OCONNELL, Primary Examiner.

10 I. A. CALVERT, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2678805 *Feb 20, 1950May 18, 1954Sutliff Wayne NHydraulic well jar
US2721056 *Feb 14, 1952Oct 18, 1955Storm Lynn WHydraulic well jar
US2922626 *Mar 25, 1957Jan 26, 1960Sutliff Wayne NHydraulic jar
US3233689 *Nov 29, 1962Feb 8, 1966Whittle FrankFluid pressure motive systems, primarily for borehole drilling
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3399741 *Feb 24, 1967Sep 3, 1968Schlumberger Technology CorpWell jar
US3526284 *Jan 13, 1969Sep 1, 1970Bossco IncDrill string shock absorber
US3729058 *Oct 21, 1970Apr 24, 1973Kajan Specialty Co IncHydraulic jarring mechanism
US3851717 *Nov 15, 1973Dec 3, 1974Baker Oil Tools IncSubstantially constant time delay fishing jar
US4098338 *Dec 27, 1976Jul 4, 1978Kajan Specialty Company, Inc.Jarring method and apparatus for well bore drilling
US4111271 *May 31, 1977Sep 5, 1978Kajan Specialty Company, Inc.Hydraulic jarring device
US4145034 *Mar 16, 1978Mar 20, 1979Hughes Tool CompanyHeat shield for a drill string shock absorbing apparatus
US4478284 *Feb 25, 1982Oct 23, 1984Bralorne Resources LimitedJar tool
US5624001 *Jun 7, 1995Apr 29, 1997Dailey Petroleum Services CorpMechanical-hydraulic double-acting drilling jar
US6290004Sep 2, 1999Sep 18, 2001Robert W. EvansHydraulic jar
US6481495Sep 25, 2000Nov 19, 2002Robert W. EvansDownhole tool with electrical conductor
Classifications
U.S. Classification175/297, 175/321
International ClassificationE21B31/00, E21B31/113
Cooperative ClassificationE21B31/113
European ClassificationE21B31/113