US2228241A - Well packer - Google Patents

Description

Jan.14,`1941. RQ BAKER Em 2,228,241'` WELL PACKER Y Jan. 14, 1941.

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R. c. BAKERv E-rAL WELL PACKER Filed May 5, 1939 2 Sheets-Sheet 2 described in detail:

Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE WELL PACKER Application May 5, 1939, Serial No. 271,940

28 Claims.

The present invention relates to well packers, and more particularly to :packers capable of employment in the cementing or repressuring of oil wells, or in testing formations for fluid permeability or breakdown pressures, or in testing casing for holes.

I-t is an object of the present invention to provide an improved well packer capable o-f being set, released and reset within the casing without the necessity for its withdrawal to the surface of the bore. If desired, ailter the setting of the packer it can be released `and removed entirely from the casing.

A further object of the invention is to minimize or completely eliminate the tendency for unintentional setting of a hydraulically operated packer within a casing.

Still another object of the invention is to provide an improved hydraulically operated tripping device for a well packer, permitting the incorporation of 4an efficiently sealed pisto-n of a smaller area, which consequently requires a greater unit pressure or fluid head to cause its movement against any definite resisting force.

A further object of the invention is to provide a Well packer having a back pressure valve requiring dissimilar degrees of pressure to induce its opening at different stages in the operation of the packer. n

The present invention has other objects that will become apparent from a consideration of one form in which it is embodied. This form is shown in the drawings accompanying and forming part `of the present specification, and it will now be However, is to be understood that this detailed description is not to be taken in a limited sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal sectional view disclosing one embodiment of the invention within a well casing, with the parts in position for running th-e device in tne casing;

Figure 2 is a view similar to Figure 1 with the slips and valve assembly shown in tripped position;

Figure 3 is a view similar to Figure 2 withithe slips shown in fully set position; and

Figure 4 is a view similar lto Figure 2 with the slips and associ-ated parts disclosed in released position.

The packer includes a generally cylindrical main body II'I, carrying a plurality of circumferentially arranged slips II thereon through the mediumof a ring or cage I2, from which pro- (Cl. 16B-12) jects a plurality of radial fingers I3 supporting T-shaped heads I4 extending from the slips. The slips are guided radially of the main body by the engagement of shank portions I5, depending from the heads, with the sides of the fingers I3. The cage or ring I2 is movable downwardly against the action of a helical retractor spring I6 abutting -a flange I'I extending from the main bodr and an inturned flange or ring I8 extending from the cage. Upward movement of the ring is limited by its engagement wi-th a stop ring I9 xed to the body. The downward movement of the cage will cause its abutment 20 to engage with the upper surface of the T-shaped heads I4 on the slips, and move the slips longitudinally of the body. Each slip I I is provided with a downwardly and outwardly tapered surface 2| engageable with an expander cone 2\2 slidable upon the main body. It will be noted that the down-ward movement of the slips in the manner aforementioned will cause their radial outward movement, in view of the engagement `between the cooperable tapered surfaces 2I, 23 on the slips and cone, which movement will continue until the wickers or teeth IIa on the exterior of each slip are engaged or embedded wi'thin the casing C.

Theexpander 22 is supported from 'the main body I0 by a retaining ring 24 Ith-readedly or otherwise suitably secu-red to the main body, and

by means of a packing sleeve 25 of rubber or the like secured to both the cone and retainer. Such securing of the packing sleeve is accomplished by seating its respective external end anges 2-6, 26 within grooves or recesses 21, 21 formed Within the cone and the retainer, each of these grooves being definedV by an inturned flange -28 seating within an external circumferential groove 29 in the sleeve formed between its main portion and outwardly directed flange. 'Ihe rubber packing sleeve 25 normally tends lto assume a distended position, urging the cone 22 upwardly towards engagement with the slips. l,Howeven this upward movement is limited by the abutting of the end of the cone with lthe ange I'I provided on the main body.

The slips are set by a trip assembly, including a complementary body 30 in the form of a trip nipple or sub, connected to the main body III of the packer by a square threaded connection 3|, preferably of lef-t hand and fairly steep pitch.

in order to permit the disconnection of the trip assembly from the main body. The trip nipple 38 slidably carries a. trip ring 32 -threadedly or otherwise secured to a. trip collar or piston 33, having an inturned portion forming an annular piston head 34, upon which uid under pressure is adapted .to act after passing -through one or more inlet ports provided in the nipple. This fluid under pressure will urge the piston downwardly against the action of a return spring 36 abutting the lower end of lthe collar at one end, and a stop ring 31 secured to the nipple at its other end. The downward movement of the piston and trip ring is limited by the engagement of an inturned flange 38 on the trip ring with the stop ring 31.

'Ihe piston 33 is sealed against leakage of fluid in opposite directions ofv its head. Seepage or now in an upward direction'is prevented by a circular sealing ring 39 seated within a V or wedge-shaped groove 40 formed on Ethe exterior of 'the nipple 30, this seal or packing engaging the interior surface of the trip collar or piston. Leakage past the piston in the other direction is prevented by providing an annular packing 4I within an internal V or wedge-shaped ring groove 42 formed within the trip collar below 'the piston head 34 and tending to urge the sealing ring 4=| into leak proof engagement with the exterior surface of the nipple. r

vThe lower end of the main packer body I0 carries a back pressure valve assembly which will permit the free passage of liquid through the en- -ti-re device, but which is also capable of causing pressure to be built up within the .packer for setting it at any place within a casing and for performing various other functions.- This valve assembly includes a guide cage 43 initially xedly secured to a depending sleeve portion 44 ot the rubber retainer 24 by means of one or more shear screws 45. Extending upwardly from the lower portion of this cage is a guide sleeve 46 slida'bly receiving a stem 41 secured to the head 48 of the back pressure valve, this head having a tapered end 48a adapted to seat upon a seal 49 of rubber or the like provided in the main body. A valve spring 50 encircles the guide and acts against the valve head to normally urge it to seating engagement with its cooperable seat. This valve head 48 is also positively held against its seat by the engagement of its depending portion 48h with the upper end of .the guide sleeve 46. Such positive seating is desirable to ensure that ports 51 or openings through the valve head will be fully closed by a slidable trip valve 52 positioned within the head. 'Ihis slide valve is normally maintained clear of the ports .by means of a frangible connector in the form of a shear screw 53 secur` ing it .to the main body I0 of the packer.

In the use of the device, the trip assembly is secured to the main body of the packer by its threaded interconnection 3|, and the upper vpart of the trip nipple is attached to the run-in string of tubing, drill pipe, or the like 54. The packer is lowered in the casing to .the desired point, there being freedom of movement of the displaced huid through the packer lby its ability to enter the main body through the openings 43a in the valve guide and the radial ports 5I within the back Dressure'valve head. Because `of this initial arrangement of valve parts, a swabbing action by in the auxiliary slide valve. Pressure can thereupon be built up within the packer until a force is exerted upon the ball and slide valve of sucient magnitude to shear the screw 53 and free the slide valve from the main body, permitting it to be moved into abutting relationship with the bottom of the back pressure valve head 48, and to a position in which Ithe ports 5I are closed. Circulation through the packer can then only be obtained by the removal of the back pressure valve head from its cooperable seat.

Initially vthis head is positively held against its seat by the positive engagement between the head porti-on 48h and guide sleeve, and by the rigid securement of the valve cage 43 to the body I0 by the frangible screws 45. This arrangement is desirable to ensure that the auxiliary slide valve 52 will be moved completely downwardly to close the ports 5I fully, and with its upper end below the sealing tapered surface of the valve head. If only the valve spring 50 offered resistance .to the downward movement ofthe valve head, a possibility would exist that foreign matter or some unforeseen condition would prevent complete movement of the auxiliary slide valve .to its lowermost position, free-from subsequent interference with t'he operation of the 'back pressure valve head.

'I'he building up of pressure Within the 'body after seating of the .ball 55 and shearing of the screw 53, which permits the slide valve to move to its lowermost position, will produce the shearing of the screws holding the valve cage 43 in xed position with respect to the body III or retainer 24. This action will occur because of the positive connection between the slide valve 52 and shear screws 45 afforded by the abutting of the lower part of .the valve head with the guide sleeve 46. As soon as the shear screws fail, the valve spring will move the cage 43 downwardly to a position limited by the engagement of the upper ends of guide slots 51 in the cage with guide stops 58 xed to .the retainer sleeve 44. It will be apparent that such lowering of the valve cage will decrease the tension in the spring 54 and remove the abutting association between the valve head and guide, permitting unseating of the valve head upon application vthereto of a suflcient pressure to overcome the force of the spring.

Upon seating of the trip ball as described y above (see Figure 2), the building up of pressure in the fluid will cause it to act upon the annular piston 34, and move its collar 33 and associated trip ring 32 downwardly against t'he action of 'the return spring 36. In pursuing this movement, the lower end of the trip ring will abut the upper portion of the ring I2 and move it downwardly against the action of its associated return spring I6. The abutment 20 on the cage will engage 4the T-shaped heads I4 on the slips and move them downwardly upon the expander cone 22 to urge the slips radially outwardly until their wickers I la engage the casing. Thereafter, the running-in string and associated trip nipple and main body will be moved upwardly (see Figure 3), producing a compression of the packing sleeve 25 into sealing engagement with the sides of the casing, and also an upward force against the cone 22, to urge the slip teeth or wickers IIa more firmly into the casin-g, ensuring that they will be held therein securely.

The packer is now in position for performing the desired operation or function within the casing. If the device is to be used as a cement retainer, .the forcing of the cement slurry down the run-in string and packer body will unseat the valve head 48, permitting the slurry to pass from the packer to the desired regions. After sufllcient cement has been forced through the body, the back pressure valve head will be seated by its associated spring 50 to prevent return flow of any fluid or plastic cement.

The device can be employed also in connection with repressuring operations, as by pumping a suitable gas through the body and out past the back pressure valve, the one-way characteristics of this valve preventing return ow of the gas. Moreover, formations may be .tested for uid permeability or breakdown pressure through the forcing of a suitable medium through the packer.

The packer can be left in the casing if desired by rotating the run-in string and trip nipple or sub in a righthand direction, which will produce a disconnection at the lefhand threads 3I between the sub and the main body I0 of the packer. However, the present invention includes the ability to remove the packer after it has been set in position, and a subsequent resetting in the same or another position within the casing without the necessity for removing the packer to the surface of the bore.

After the packer has been set and the desired function accomplished, the pressure Within the main body and the trip nipple can be relieved, and the run-in string and nipple and body connected thereto moved downwardly (see Figure 4) to distend the packing sleeve 25 and move the expanding cone 22 downwardly from contact with the slips II. This will permit the return trip spring 36 to move the piston to its initial position and correspondingly move the trip ring 32 from engagement with the cage I2, allowing the energy previously stored in the retractor spring I6 to move the cage upwardly and the slips out of engagement with the casing and free from functional cooperation with the tapered surface 23 of the cone. An encircling coil spring 59 engagging within a circumferential groove 60 in each of the slips is provided to move them radially inwardly upon the removal of the cone from its operative position.

The run-in string can now be raised or lowered to position the packer at any other desired point within the casing, after which the pumps can be started and pressure built up to move the piston 34 downwardly and cause its associated trip ring 32 to engage the cage I2 and force the slips I I downwardly upon the expanding cone 22 into engagement with the casing. Upon taking a strain on the run-in string the packing sleeve .25 can again be compressed to engage with the casing, and its associated cone urged more strongly against the slips. 'Ihe device is now in condition for performing the desired function at its new location.

The packer can again be released and set at another position. 'I'his ability to be alternately set and released permits its utilization as an instrument for testing casing for holes or fractures, simply by setting the packer at various positions within the casing and thereafter applying pressure until the defect in the casing is noted through the inability to build up sufficient pressure within the run-in string and packing device.

After shearing of the screws holding the back pressure valve guide or cage to the retainer sleeve, the valve spring will limit the effective pressure upon the annular piston 34, and conse- `cluently limits the force that can be exerted downwardly upon the slips. This total force is a function of the unit pressure differential in the region of the piston and the piston area on which uid can act. Heretofore, such annular pistons have been of an unrequired large area, which would unduly multiply the downward force exerted upon them, and which in some instances might cause an undesired setting of the slips, as, forl example, upon raising of the packer in the casing. en this operation is performed, the tubing or drill pipe might extend a hundred feet or more above the surface of the bore, the uid coni-ined therein creating a sufficient pressure differential to move the piston downwardly to set the slips. The piston area has previously been of a large size because of the necessity for effecting a proper seal between it and its relatively stationary cooperable part, as the trip nipple or sub 30 of the instant application. Usually a U-shaped or similar sealing ring has been employed at the head of the piston. In the present invention, it is proposed to produce the sealing action at a point remote from the pressure active surface of the piston, and to employ a seal of such character as to require a minimum of radial space in effectively performing its required functions.

Referring to the drawings as heretofore described, annular seals are provided on opposite sides of the piston head 34, the sealing rings 39, 4I being circular in cross-section, and cooperable with the tapered sides of their confining grooves 4D, 42. 'I'he removal of these sealing elements from the active head of the piston permits the reduction of the piston area to any desired radial dimenison, which can be as low as that actually needed to move the slips downwardly against the action of the springs 36, I6. In sliding of the rings 38, 4I upon the nipple 30 or collar 33. an effective seal is obtained because of the tendency of each rubber or leather packing ring to move axially of the wedge groove into a longitudinally converging space between the groove and its opposed member, causing a compression of the rings into intimate sealing engagement between the piston or trip collar and the nipple.

We claim:

1. In a device of the character described, the combination of a body adapted to be positioned within a well casing, slips carried by said body, an expander slidably carried by said body for moving said slips into engagement with said casing, an elastic packer xed to said expander and to said body, and hydraulically actuated means for moving said slips longitudinally along said expander` into contact with the casing.

2. In a device of the character described, the combination of a body adapted to be positioned within a well casing, slips carried by said body, an expander slidably carried by said body for moving said slips into engagement with said casing, an elastic packer surrounding said body and fixed to said expander, and hydraulically actuated means for moving said slips longitudinally along said expander into contact with the casing independently of any movement of said expander.

3. In a device of the character described, the combination of a body adapted to be positioned within a well casing, slips carried by said body, an expander slidably carried by said body for moving said slips into engagement with said casing, an elastic packing surrounding said body and xed to said expander on one side thereof,- and hydraulically actuated means on the other side of said expander operable to move said slips longitudinally along said expander into contact with the casing.

4. A well packer, including body means adapted to be positioned within a well casing, slips carried by said body means, an expander carried by said body means for moving said slips into engage'- ment with said casing, hydraulically operated means for moving said slips into engagement with said expander, comprising an annular piston surrounding said body means, said piston being provided with a ring groove below its head, and a sealing ring in said groove engageable with said body means.

5. A well packer, including body means adapted to be positioned within a well casing, slips carried by said body means, an expander carried. by said body means for moving said slips into engagement with said casing, hydraulically operated instrumentalities for moving said slips with respect to said expander, comprising annular piston means surrounding said body means, one of said means being provided with a ring groove in its side wall, and a sealing ring in said groove engageable with the other of said means.

6. A well packer, including body means adapted to be positioned within a well casing, slips carried by said body means, an expander carried by said body means for effecting movement of said slips into engagement with said casing, hydraulically operated instrumentalities for producing relative movement'between said slips and expander, comprising annular piston means surrounding said body means, one of said means being provided with a ring groove in its side wall, and a sealing ring in said groove engageable with the other of said means.

7. A Well packer, including body means adapted to be positioned within a well casing, slips carried by said body means, an expander carried by said body means for moving said slips into engagement with said casing, hydraulically' operated means for moving said slips with respect to said expander,l comprising an annular piston surrounding said body means, said piston having a head and being provided with a ring groove below said head, a sealing ring in said groove engageable with said body means, said body means being provided with a ring groove above said head, and a sealing ring in said body groove engageable with said piston.

8. A well packer, including body means adapted to be positioned within a well casing, slips carried by said body means, an expander carried by said body means for moving said slips into engagement with said casing, hydraulically operated instrumentalities for moving said slips with respect to said expander, comprising annular piston means surrounding said body means, one of said means being provided with a ring groove, and a sealing ring in said groove engageable with the other of said means, said groove havingtapered side walls for urging said sealing ring radially against the other of said means upon relative longitudinal movement therebetween.

9. A well packer, including a body adapted to be positioned within a well casing, slips carried by said body, an expander carried by said body for moving said slips into engagement with said casing, hydraulically operated means for moving said slips with respect to said expander, and a detachable connection between said body and hydraulically operated means permitting their disconnection while in the casing.

10, A well packer, including a body adapted to -be positioned within a well casing, slips carried by said body, an expander carried by said body for moving said slips into engagement with said casing, hydraulically operated means for moving said slips with respect to said expander, comprising a complementary body, piston means and spn'ng means carried by and between said complementary body and piston means, said complementary body being detachably secured to said inst-mentioned body to permit its disconnection therefrom while in the casing together with said piston means and spring means.

11. A well packer, including a body adapted for positioning within a well casing, slips carried by said body, an expander carried by said body for moving said slips into engagement with said casing, spring means normally urging said slips away from said expander, means comprising a piston for moving said slips into engagement with said expander, and spring means for moving said piston away from said slips.

12. A well packer, including a body adapted for positioning within a well casing, a plurality of slips disposed circumferentially around said body, a ring mounting said slips, an expander carried by said body for moving said slips into engagement with said casing, a spring supported on said bodyfor urging said ring away from said expander, means engageable with said ring for moving it toward said expander, and a second spring for moving said means away from said ring. 1

13. A well packer, including a body adapted for positioning Within a well casing, a plurality of slips disposed circumferentially around said body, a ring mounting said slips, an expander carried by said body for moving said slips into engagement with said casing, a spring supported on said body for urging said ring away from said expander, a nipple detachably secured to said body, apiston slidable on said nipple and engageable with said ring for moving it toward saidexpander, and a second spring supported on said nipple for moving said piston away from said ring.

14. A well packer, including a body adapted for positioning within a well casing, a plurality of slips disposed circumferentially around said body, a ring mounting said slips, an expander carried by said body for moving said slips into engagement with said casing, a spring supported on said body for urging said ring away from said expander, nipple means detachably secured to said body, piston means including a head slidable on said nipple and engageable with said ring for moving it toward said expander, a second spring supported on said nipple for moving said piston means away from said ring, one of said means having a generally wedge-shaped ring groove below said head confining a sealing ring for engagement against the other of said means.

15. A back pressure valve, including a valve seat, a valve head, means positively holding said head against said seat, and' means yieldably urging said head against said seat upon rendering said positive holding means ineffective.

16. In a well packer, a valve seat, a valve head, means including a frangible connector for positively holding said head against said seat, and.

means yieldably urging said head against said seat upon failure of said connector.

1'?. In a well packer, a body through which uid is adapted to pass, a valve seat on said body, a valve head having av port therein permitting passage of uid, means positively holding said head against said seat, and a valve adapted to close said port, whereby to prevent passage of fluid therethrough.

18. In a well packer, a bodythrough which iluid is adapted to pass, a valve seat on said body, a valve head having a port therein permitting passage of uid from said body, means yieldably holding said head against said seat, and a valve adapted to close said port, whereby to prevent passage of fluid therethrough.

19. In a well packer, a body through which fluid is adapted to pass, a valve seat on said body, a valve head having a port therein permitting passage of fluid from said body, means positively holding said head against said seat, means yieldably urging said head against said seat, and a valve adapted to close said port whereby to prevent passage or iluid therethrough.

20, In a well packer, a body through which iluid is adapted to pass, a valve seat on said body, a valve head having a port therein permitting passage of fluid from said body, means positively holding said head against said seat comprising a frangible connector, a spring engageable with said means for yieldably urging said head against said seat, a slide valve within said valve head to close the port therein, and a frangible connector securing said slide valve to said body to maintain it clear of said port.

21. In a well packer, a body through which iluid is adapted to pass, a valve seat on said body, a valve headhaving a port therein permitting passage of fluid from said body, a guide for said head, a frangible connector securing said guide to said body to positively hold said head against said seat, a spring carried by said guide for yieldably urging said head against said seat, a slide valve within said valve head to close the port therein, a frangible connector securing said slide valve to said body to maintain it clear of said port, and a lost motion connection between said guide and body permitting limited movement of said guide away from said head upon failure of said first-mentioned frangible connector.

22. In a well packer, a body through which iluid is adapted to pass, a valve seat on said body, a valve head, a guide for said head, a frangible connector securing said guide to said body to hold said head positively against said seat, a spring carried by said guide for yieldably urging said head against said seat, and a lost motion connection between said guide and body permitting limited movement of said guide away from said head upon failure of said irangible connector.

23. In a well packer, a body through which fluid is adapted to pass, a valve seat on said body,

a valve head, a guide for said head, frangible means securing said guide to said body to hold said head positively against said seat, and means carried by said guide for yieldably urging said head against said seat upon failure of said frangible means.

24. In a device of the character described, the combination of a body adapted to be positioned within a well casing, initially retracted means adapted to engage said casing, means coupling said initially retracted means to said body both While retracted and in engagement with the casing, expander means slidably carried by said body for moving said initially retracted means into engagement with said casing, and hydraulically operated means for moving said initially retracted means into engagement with said expander means.

25. In a device of the character described, the combination of a body adapted to be positioned within a well casing, an expander slidably carried by said body, slips cooperable with said expander for anchoring said body to said well casing,

hydraulically actuated means for moving said slips along said expander into contact with the casing independently of movement of said expander, and means coupling said slips to said body while they are anchored to the casing.

26. In a device of the character described, the combination of a body adapted to be positioned in a well casing, an expander slidably carried by said body and having a downwardly diverging outer surface, slips cooperable with said expander for anchoring said body to said well casing, hydraulically actuated means for moving said slips downwardly to their fullest extent along said expander surface into contact with the casing, and means coupling said slips together and to said body while they are anchored to the casing.

27. In a device of the character described. the combination of a body adapted to be positioned in a well casing, an expander slidably mounted on said body, normally retracted slips cooperable with said expander for anchoring said body to said well casing, hydraulically actuated means for moving said slips along said expander into in a well casing, an expander slidably mountedv on said body, normally retracted slips cooperable with said expander for anchoring said body to said well casing, hydraulically actuated means for moving said slips along said expander into contact with the casing independently of movement of said expander, and means for coupling said slips to said body and for removing them from engagement with said casing to their normally retracted position.

REUBEN C. BAKER. CLARENCE E. BURT. THOMAS M. RAGAN.

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