US2645459A - Hydraulic jar - Google Patents

Description

w. N. ,suTLu-'F Hmmm JAR;

July 14, T953` 2 Sheets-Sheet l Filed Aug. 6, 1951 July 14, 19:53 l w. N. s-UTLIFF 2,645,459

HYDRAULI JAR Patented .uly 1.4,

Wayne N. Sutli", Bakersfield, Calif. Application August c, 1951, seria1N0.240,4s7

This invention relates to an oil well tool and particularly to a hydraulic well jar of the typev including a hammer and anvil, in which the hammer is retarded when urged toward the anvil to tension the drill string or wire supporting the well jar, and then released to cause a violent impact between the hammer and anvil. The present application is a continuation-in-part application of my prior co-pending application entitled,

Hydraulic Well Jar and Method of Use, Serial No. 49,973, iiled September 18, 1948, now abandoned.

As is well known to those skilled in the art, Well I jars are connected to twistedoff strings of drill pipe and other objects that become lodged or stuck in well bores for the purposes of jarring the lodged or stuck members in an effort to loosen them for removal.

Hydraulic well jars of the type described above have the advantage of being simple in construction, including few parts, and wearing less rapidly than mechanical well jars. However, these hydraulic well jars have not been dependable in operation, in many instances functioning for only a few jars and then ceasing to operate properly, necessitating their removal and adjustment or repair. I believe that this defect in operation is caused by the creation of voids in the hydraulic fluid chamber in the well jar.` 'I believe that .these voids Idetrimentally affect the operation of such a well jar by preventing the-extent of retardation of the hammer necessary to sufliciently tension the drill string or wire line to cause a violent impact between the hammer and anvil upon release of the hammer. These voids may be formed or created inseveral ways. Thehydraulic fluid chamber may notbe entirely filled when the -well jar is prepared forA use.` The high internal hydraulic pressures created in the well jar on the high pressure side of the hammerV during operation may cause leakage past the packing'on the high pressure side, or leakage can occur past the other packing in the well jar.

It i'sa main object of the present invention to provide a hydraulic well jar having a hydraulic iluid chamber including a compensating floating piston. exposed on one side. to the pressure of the well iluid andon the opposite side to the low pressure side of the hammer, so that when the well jar is lowered into a well, the pressure of the well f the volume thereof is equal to the hydraulic fluid therewithin, whereby existing voi-ds in the hydraulic fluid chamber are eliminated and the 4 claims. (01255-27) Ii-formation of new voids ncausable by leakage of hydraulic fluid from the chamber is prevented. This floating compensating piston structure is disclosed in my prior co-pending application above identified.

Another object of the present invention is to provide an improved hydraulic well jarjparticularly one having an improved valve arrangement. The valve arrangement of the present application, though being broadly similar to, is specifically `different from the one shown in my prior identilied co-pending application.

Various other objects will be apparent from the following description taken in connection with f the accompanying drawings, wherein:

Fig. 1 discloses a well jar embodying the concepts of the present invention being shown in quarter section. Y

Fig, 2 is an enlarged sectional View, through a portion of the well jar disclosed in Fig. 1, showing the valve closed and the hammer in the process of being pulled upwardly toward the anvil.

Fig. 3 is a View, similar to Fig. 2, showing the hammer after having been released and` in engagement with the anvil.

Fig. 4 is a view, similar to Fig. 2,showing the hammer being moved downwardly and the valve being open.

Fig. 5 is a View showing themanner of attachment of the hydraulic well jar to a wireline.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the hydraulic well jar has a' hydraulic iluid chamber formed by a valve housing 9, which has a lower sub `Il secured to 'the lower end thereof, and an upper sub I3 secured to the upper end of valve housing 9. This hydraulic fluid chamberis lled with a suitable hydraulic fluid, such as oil, through ports I4 in valve housing 9 closed by pipe plugs Illa.

A central composite mandrel I5 extends through the hydraulic chamber and, adjacent its upper end, sealingly `engages upper packing |1, carried by upper sub I3, and, vadjacent its ,lower end, sealingly engages lower packing I9, carried rby lower sub I I. Above lower packing I9, there is a floating compensating annular piston/2| slide ably received within valve housing sand slidably receiving the lower end of composite mandrel l5. The hydraulic fluid is therefore contained within tubular housing 9 and upper sub I3 and between upper packing I'l and iioating piston 2I Further reference to the floating will be made hereinafter.

Upper packing il is adapted to be held in place by arpacking nut 23 threadedly received within the upper end of upper sub I3, and lower packing compensating piston 2|A Y the -anvil andfluid passageways formed on the outer surface of said mandrel inwardly of the valve for bypassing the valve when the valve is unseated, said passageways extending from a point Vbeyond the valve seat toward the hammer and beyond theV valve and being closed by the valve against fluid passageV past the valve seat when said valve is close-d, spring means urging the valve toward its seat to seal "off the passageways, and a floating compensating annular piston slidably received by the chamber and slidably receiving the mandrel, exposed on one side to the Vpressureofthe hydraulic fluid in the chamber and' on its opposite side to the pressure of the vwell lfluid, operable, whenthe well jar is lowered into a well andthepiston is subjected to the well valve seat formed thereon facing axially toward Y fluidin the space between the hammer and anvil operable to'suddenly releasethe fluid to effect a sudden movement of the-hammer toward the anvil, the improvement which comprises the provision of a passageway communicating'the interior of the chamber with the exteriorthereof,

andan annular floating piston surrounding the mandrel and dimensioned to snugly fit against the `interior, walls of the. chamber and Vonzthe mandrel to seal against both members,A said pis- Y ton being exposed on one side to the pressure of fluid pressure, to eliminate existing voids in the hydraulic fluid chamber and prevent the formation of new voids, causable by leakage of hydraulic fluid from the cham-benby shifting under the influence of a differential pressure created by the voids or leaking fluid to reduce the volume of the hydraulic fluid chamber to an extent-where the volume of the hydraulic fluid chamber ist;

equal to the volume of thefluid therewithin.

vthe hydraulic fluid in the chamber and on its opposite side to the pressure of the well fluid and being operable when the jar is lowered into a well and the piston is subjected to the well fluid pressure, to eliminate existing voids in the hydraulic fluid chamber and prevent the forma- 2. A hydraulic well jar, comprising a hollow fluid-tight housing adapted to'be secured to a flsh lodged in a well and providing a hydraulic .uid` chamber deflnedl in part Iby a large bore portion and aV small bore portion, an anvil within the large bore portion of lthe housing, a mandrel Y adapted to be reciprocated by a drill string or wire line and slidably received within the housing and carrying a hammer adapted to be brought `into violent contact with the anvil,` an annular valve on the mandrel dimensioned to slidably fit within the small bore and over the mandrel and being operable to retard movement of the hammer toward the mandrel when the valve is disposed within the small bore'portion of the housing to cause tensioning of the drill string or equivalent structure and to suddenly release the hammerwhen moved to a position within the large =bore portion of the housing to allow the hammer to violently strike the anvil, said mandrel hav- Y :ing a valve seat formed thereonV facing axially toward the anvil and fluid passageways formed on the outer surface of said mandrel inwardly of the valve for bypassing the valve when the valve is unseated, said passageways extending from a point beyond the valve seat toward the hammer and beyond the Valve and being closed by the valve against fluid passage past the valve seat when said valve is closed, and spring means urging the valve toward its seat lto seal off the passageways, and a floating compensating annular piston slidably received within the chamber at a point to be exposed to the pressure on the side of the hammer remote from the anvil, and slidably receiving the mandrel, and exposed on its opposite side to the pressure of the well fluid, operable, when the well jar is lowered into a well and the piston is subjected to the well fluid pressure, to eliminate existing voids in the hydraulic fluid chamber and prevent the formation of new voids, causable by leakage of hydraulic fluid from the chamber, by shifting under the influence of a differential pressure created by the voids or leaking fluid to reduce the volume of Vthe hydraulic fluid chamber to :an extent where the volume of the hydraulic fluid chamber isequal to the volume of the fluid therewithin.

3. In a hydraulic `well jar of the type having a hydraulic fluid chamber reciprocably receivingr tion '.of new voids, causable by leakage of hydraulic fluid from the chamber, by vshifting under the influence of differential pressure created bythe existing voids or by leaking fluid to reduce the volume of thehydraulic fluid chamber to an extert where the volume thereof is equal to the volume of fluid therewithin.

4. In a hydraulic well jar of the type having a hydraulic fluidchamber reciprocably receiving a mandrel, and wherein a hammer isy provided Y on one of the parts in axial alignment and adapt- Y 'lol ed to be brought into violent engagementwith an anvil provided on the other of the parts upon relative movement between vthe -chamber and mandrel in one direction, the improvement which comprises the provisionof a passageway communicating the interior of the chamber-with the exterior thereof, an annular resilient floating piston Vsurrounding the mandrel and dimensioned to snugly llt against the interior walls of the chamber and on the mandrel to seal against both members, said piston being exposed on one side tothe pressure of the hydraulic fluid inthe chamber and onits opposite side to the pressure of the well fluid and being operable when the jar is lowered into a well and the piston'is subjected to the well fluid pressure, to eliminate existing voids in the hydraulic fluid chamber and prevent the formation of new voids, causable by leakage of hydraulic fluid from the chamber, by shifting under the influence of differential pressure created by the existing voids or by leaking fluid to reduce the volume of the hydraulic fluid chamber to 'an extent where the volume thereof is equal to the volume'of fluid therewithin, and means for trapping fluid in the space between the hammer and anvil operable to suddenly release the fluid to effect a sudden movement of the hammer toward the anvil, said piston being located on the side of the hammer remote lfrom the anvil so that it is not `subjected to the extreme pressures created in the space between the hammer and the anvil.

WAYNE N. SUTLIFF.

References Cited in the file of this patent

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