US3253656A - Straight-set retrievable packer - Google Patents

Description

May 31, 1966 c. c. BROWN STRAIGHT-SET RETRIEVABLE PACKER 2 Sheets-Sheet 1 Filed Aug.

CICERO CLBROW/V INVENTOR ATTORNEY y 1, 1966 c. c. BROWN 3,253,656

STRAIGHTSET RETRIEVABLE PACKER Filed Aug. 5, 1963 2 Sheets-Sheet 2 I C/CERO 6. BROWN y I NVENTOR.

NM BY A TERA/E) 3,253,656 STRAIGHT-SET RETRlEVABLE PACKER Cicero C. Brown, Brown Oil Tools, Inc., P.O. Box 19236, Houston, Tex.

Filed Aug, 5, 1963, Ser. No. 299,910 7 Claims. (Cl. 166129) This invention relates to well packers and to improvements in packers of the straight-set type.

Straight-set packers are understood in the art to mean packers which may be set and released solely by longitudinal movement of the setting mandrel. Such straightset packers are employed where, due to the conditions of the well bore or other factors commonly encountered, it is undesirable to employ a type of packer which requires relative rotation between the setting string and the packer elements to actuate or release the packer.

It is a primary object of this invention to provide an improved form of straight-set packer which is universally useable for various well-treating processes, such as squeezing, fracturing, and the like, as well as in well production operations.

A further object is the provision of a well packer of the straight-set type employing a novel arrangement of internal and external seal elements and latching elements by which the parts are releasably secured in inactive position, but are readily actuated in response to longitudinal movements of the operating string.

An additional object is to provide a packer construction employing a central mandrel on which are mounted a main packer unit, an anchor assembly, and an internal seal unit disposed for inter-engagement in response to longitudinal movements of the mandrel relative to the packer and anchor units.

A more specific object is the provision of a novel form of releasable latch between the packer assembly and the mandrel for holding the packer assembly in inactive position during running of the packer into the well.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiment in accordance with this invention.

In the drawing:

FIG. 1 is a longitudinal quarter-sectional view, showing the packer in the unset position as it is run into a casing lining a well bore;

FIG. 2 is a view similar to FIG. 1, showing the packet elements at an intermediate stage during the setting operations;

FIG. 3 is a view similar to FIG. 1, showing the packer in set position; and

FIGS. 4, 5, 6 and 7 are cross-sectional views taken, respectively, along lines 44, 5-5, 66 and 77 of FIG. 3.

The packer structure, which is insertable into a well casing W, includes a tubular mandrel M adapted to be connected into an operating pipe string T between upper and lower threaded collars C and C respectively, which forms downwardly and upwardly facing shoulders 10 and 11, respectively, at spaced points along the mandrel. A series of sub-assemblies are slidably supported on mandrel M and comprise an upper latch and inner seal assembly L mounted about the upper end of the mandrel,

the main packer assembly S positioned about the mandrel below assembly L, and an anchor assembly A disposed about the mandrel below packer assembly S. In their initial positions, the several assemblies are supported in spaced apart relation on mandrel M by means of releasable latch elements, to be described more fully hereinafter, but are arranged to be inter-engaged in response to rela- United States Patent 0 Patented May 31, 1966 tive vertical movements of the mandrel, as will appear hereinafter.

Latch and inner-seal assembly L, which is of the same general form and arrangement disclosed in my co-pending application Serial No. 756,552, filed August 28, 1958, now Patent No. 3,136,366, includes a seal packing 12 molded to upper and lower end rings 13 and 14, respectively, the packing unit being disposed for limited sliding movement on mandrel M between longitudinally spaced upper and lower snap rings forming external shoulders 15 and 16, respectively, about mandrel M. Slidably mounted about the latter above the seal packing is a latch sleeve 17 slotted longitudinally from its lower end to form a series of circumferentially arranged flexible latch fingers 18 terminating at their lower ends in outwardly projecting latching dogs 19. The latter have bevelled inner faces 20 adapted to engage an upwardly tapering conical expander surface 21 formed on upper end ring 13. 'A third snap ring 15a is mounted in the exterior of mandrel M to form an external shoulder a short distance above shoulder 15 and is adapted to be engaged by an internal shoulder 17a provided at the upper end of latch sleeve 17 to limit downward movement of the latter on mandrel M. Relative upward movement of sleeve 17 on mandrel M is limited by shoulder 10 defined by upper collar C.

Main packer assembly S includes a tubular packer body 22 having a counterbore 23 at its upper end adapted to sealingly receive seal packing 12 and latching dogs 19. Counterbore 23 is provided internally, near its upper end, with a latching groove 24 for latching engagement by dogs 19 when the latch assembly has been inserted in body 22, as will appear subsequently. An annular, flexible, resilient packer or seal element 25 is positioned about an intermediate portion of body 22 and is secured to upper and lower metal end rings 26 and 27, respectively. Upper end ring 26 is fixedly secured to body 22, while lower end ring 27 and seal element 25 are free to slide on body 22, seal elements 25 being radially expansible in response to end-wise compression exerted upwardly through lower end ring 27 against the fixedly positioned abutment formed by upper end ring 26. An external upwardly facing shoulder 24 provided near the lower end of body 22, co-operates with a downwardly facing in ternal shoulder 28 on end ring 27 to limit downward movement of the seal element on body 22. A plurality of generally conventional wickered hold-down buttons 29 will be mounted for radial movement in the wall of body 22 above the seal element and are adapted to be urged outwardly in response to hydraulic pressure interiorly of body 22 for engaging the wall of well casing W.

Lower end ring 27 has attached thereto surrounding body 22 a tubular slip cone B0 haw'ng a bore wall 30a and provided at its lower end with a downwardly and inwardly tapering external slip expander surface 31. Bore wall 30a is provided with an internal annular recess 32 extending over its lower portion. The upper portion of bore wall 30:: has a diameter such as to have close sliding engagement with the exterior of the portion of body 22 which extends below shoulder 24. A radial port 33 is provided through the wall of body 22 below shoulder 24 and is adapted to communicate with a radial port 34 extending through the wall of slip cone 30 when shoulders 28 and 24 are in engagement, whereby to provide fluid communication between the bore of body 22 and the exterior of the packer assembly.

Mandrel M is provided intermediate its ends at about its mid-point with an external annular shoulder 35 adapted to be engaged by the lower end of body 22 to limit downward movement of the packer assembly relative to the mandrel. A latch means is provided for releasably hold ing body 22 in the shoulder-engaging position and includes a plurality of circumferentially arranged positioning lugs mounted for radial movement in slots 37 extending through the wall of body 22 just above the lower end thereof. Lugs 36 have a radial length greater than the wall thickness of the lower portion of body 22 so as to be projectable from slots 37 into an annular latching groove 38 provided in the exterior of mandrel M just above shoulder 35 when the opposite ends of lugs 36 are engaged by bore wall 30a of the slip cone. It will be evident that when such relative longitudinal movement occurs between slip cone 30 and packer body 22 as to move recess 32 opposite lugs 36, the latter will be freed for retractive movement out .of groove 38, thereby releasing mandrel M for longitudinal downward movement relative to packer assembly S.

Anchor assembly A, which is positioned below packer assembly S, includes a tubular slip cage 40 on the upper end of which a plurality of upwardly extending circumferentially arranged pipe-gripping slips 41 are mounted for radial movement. The outer faces of the slips have the usual pipe-gripping teeth 41a and the inner faces of slips 41 are provided with upwardly and outwardly bevelled surfaces 42 for cooperative engagement with tapered surfaces 31 of slip expander cone 30. Cage 40 is provided with an external annular recess 43 in which are mounted for limited radial movement a plurality of friction pads 44, separated by spacer blocks 44a. Pads 44 are biased outwardly by means of coil springs 45 to frictionally engage the wall of casing W.

The lower end of cage 40 supports still another latch mechanism which comprises a'tubular sleeve 46 surrounding mandrel M and having an internal ledge 47 on which a plurality of latch segments 48 are rockably mounted for movement inwardly and outwardly of sleeve 46. A garter spring 48a is mountedto encircle the outer peripheries of the latch segments to bias them toward mandrel M. The upper ends of latch segments 48 define shoulders 49 adapted to engage beneath an external shoulder 50 provided on mandrel M at a suitable spacing below shoulder 35. As in the position illustrated in FIG. 1, it will be seen that latch segments 48 will be engaged beneath shoulder 50 so as to prevent relative downward movement of mandrel M. Mandrel M carries a release mechanism for releasing latching segments 48 from their engagement beneath shoulder 50. This release mechanism comprises a trip sleeve 51 slidably mounted on the mandrel below shoulder 50 and is provided with an external shoulder 52 at its lower end of greater diameter than the bore of ledge 47. In the inactive position seen in FIG. 1, trip sleeve 51 will rest on shoulder 11 defined by lower collar C At its upper end trip sleeve 5-1 has ;a shoulder 53, the external diameter of which is such as to permit it to slide freely through bore 46a of ledge 47, Shoulder 53 merges into a downwardly and inwardly tapering surface 54 extending to the exterior of sleeve 51. Trip sleeve 51 will be operated to release the engagement between the latch segments and shoulder 50 in response to the longitudinal movement of the mandrel, as will be described hereinafter. This last-described latch mechanism, while differing in detail, is of the same general form and function as that described in my U.S. Patent No. 2,884,069 and is intended to be generally illustrative of a form of latch which is releasable by a series of reciprocative longitudinal movements of the operating string and mandrel.

Operation of the described device is as follows: The packer structure, with the parts positioned as shown in FIG. 1, will be run into casing W. As shown, body 22 will be engaged with shoulder 35 on the mandrel and positioning lugs 36 will be seated in latching groove 38. Also, by reason of the frictional engagement of pads 44 with the wall of easing W, which restrains movement of the anchor assembly, shoulder 50 on the mandrel will engage the upper ends of latch segments 48, whereby the:

4 several sub-assemblies will be held in the spaced relation illustrated in FIG. 1.

When the structure has been moved to the desired location in casing W, operating string will be raised, raising mandrel M until trip sleeve 51 seated on shoulder 11 has been drawn upwardly inside sleeve 46 moving shoulder 53 inside the latch segments and forcing them outwardly against the resistance of garter spring 48a until shoulder 53 has moved slightly above the upper ends of the latch segments 48. This upward movement will be limited by the engagement of shoulder 52 With the lower end of sleeve 46. This position of the parts is shown in FIG. 2. Thereupon, the operating string carrying mandrel M is lowered and the latter will move downwardly relative to trip sleeve 51 as the latter will be held in the raised position by the frictional engagement of latch segments 48 on tapered surface 54 under the pressure of garter spring 48a. When the string has been lowered to the point where shoulder 50 abuts the upper end of shoulder 53 on the trip sleeve, the latter will be forced downwardly past latch segments 48. Shoulder 50, which will have approximately the same external diameter as shoulder 53 will then move with shoulder 53 below latch segments 48, thereby releasing the. mandrel for further downward movement relative to the anchor assembly. As the mandrel is lowered further, slip expander cone 31 will move inside slips 41, as seen in FIG. 3, expanding the latter into gripping engagement wit-h the wall of casing W and stopping further downward movement of the assembly. However, as further weigh-t is applied to the operating string, packer body 22 carrying seal element 25 will move downwardly relative to slip cone 30, causing endwise compression of packer element 25 and expanding it radially into sealing engagement with the wall of easing W. The resulting downward movement of body 22 relative to slip cone 30 will move positioning lugs 36 opposite recess 32, allowing the positioning lugs to retract from latching groove 38 and releasing the mandrel for downward movement relative to the packer assembly. The continued downward movement of the mandrel will move latch and seal assembly L inside counterbore 23 and packing 12 will seal off the annular space between mandrel M and the packer body above hold-down buttons 29. Dogs 19 will move into latching groove 24, being held in latching engagement in the groove by upper end ring 13, which will be in engagement with shoulder 15.

When this series of operations have been completed, the packer will .be set, being anchored to the well wall by slips 41 and packed-off through the expansion of seal element 25. At the same time, packing 12 having sealed off the annular space between the mandrel and the packer body, will permit pressure from below to flow through this annular space and actuate hold-down buttons 29 to cause them to engage the wall of casing W and hold the packer against upward movement under such pressure from below. Pressure from below the packer, which is acting upward against the mandrel M and packing 12, tending to push the mandrel M and packing 12 out of the packing body 22, will act through the packing 12, end ring 13, and tapered surface 20 to urge the latch dogs 19 outward into latching groove 24, thereby pressure-locking the mandrel M into engagement with packing body 22.

Torelease the packer, an upward pull is applied to operating string T to lift mandrel M straight upwardly. Through engagement of latch dogs 19 with latching groove 24, body 22 will begin to move upwardly, relieving the weight from seal element 25 which will then partially retract. As body 22 is further elevated it will move upwardly relative to slip cone 30 until the outer ends of positioning lugs 36 engage the upper wall of recess 32 momentarily stopping the relative upward movement of body 22. A continued upward pull on mandrel M will then bring shoulder 15a into engagement with shoulder 17a of the upper latch sleeve and will exert an upward pull on latch dogs 19. The reaction of the latter against the upper wall of latching groove 24 will force the latching fingers inwardly, pushing seal packing 12 downwardly sufficiently to allow the latch dogs to clear groove 24 and permitting further upward movement of mandrel M relative to the packer and pulling the latch and seal assembly L out of counterbore 23. As mandrel M moves upwardly, shoulder 35 will move up against the lower end of body 22, placing latching groove 38 in registration with positioning lugs 36 and allowing them to project into groove 38, thereby returning body 22 to its initial inactive position. Shoulder 2.4 will now engage beneath shoulder 28 on lower end ring 27 of the packer assembly and will exert an upward pull on slip cone 30 as the mandrel continues to be pulled upwardly. This will pull slip cone 30 from under slips 4-1, releasing the slips from the casing wall. As the mandrel continues its upward movement, trip sleeve 51 will again enter the bore of sleeve 46 and shoulder 52 will engage the lower end of sleeve 46, so that the continued upward movement of the tubing string will pull anchor assembly A and all of the packer structure upwardly out of the casing.

If it is desired to reset the packer at a higher elevation, the structure may now be moved to such elevation and be reset by a sequence of vertical movements exactly as those previously described. If it is desired to reset the packer at a lower elevation, then the tubing string would only be picked up enough to release the cone from the slips and bring shoulder 50 above the latch segments 48, but not enough to bring the trip sleeve 51 up under the latch segments. Then the packer may be lowered through the well and reset by a sequence of vertical movements exactly as thoes previously described.

From the foregoing, it will be evident that a packer structure has been provided which meets the several objects enumerated and which is highly useful in well operations.

It will be understood that various alterations and changes may be made in the details of the illustrative embodimentwithin the scope of the appended claims,

but without departing from the Spirit of this invention.

What I claim and desire to secure by Letters Patent is:

1. In a well packer of the straight-set type, a tubular mandrel connectible to an operating pipe string, a tubular packer body slidably mounted about the mandrel, an annular radially expansible seal element mounted about the packer body having its upper end fixedly secured to the body and its lower end free for relative longitudinal movement, a slip cone carried by said lower end of said seal element for said movement therewith, a slip cage slidably mounted on the mandrel below the packer body and carrying means for frictionally engaging a surrounding well wall, radially movable wall-gripping slips mounted on the slip cage below said slip cone, cooperating latch elements arranged on the mandrel and the slip cage for initially securing said mandrel against downward movement relative to said slip cage, means carried by the mandrel operable by reciproca-tive longitudinal movement of the mandrel relative to the slip cage to release said latch ele ments to thereby release said mandrel 'for said downward movement whereby to move said slip cone into expansive engagement with said slips, additional cooperating latch elements arranged between the mandrel and the packer body to initially secure the mandrel against downward movement relative to the packer body and releasable by relative longitudinal movement between the packer body and said slip cone produced by engagement of the latter with the slips whereby to free said mandrel for downward movement relative to the packer body, and latch means of the straight-pull release type mounted on the mandrel above the packer body for latching the mandrel thereto upon completion of said downward movement of the mandrel relative to the packer body.

2. In a well packer of the straight-set type, a tubular mandrel connectible to an operating pipe string, a tubular packer body slidably mounted about the mandrel, an annular radially expansible seal element mounted about the packer body having its upper end fixedly secured to the body and its lower end free for relative longitudinal movement, a slip cone carried by said lower end of said seal element for said movement therewith, a slip cage slida'bly mounted on the mandrel below the packer body and carrying means for frictionally engaging a surrounding well wall, radially movable wall-gripping slips mounted on the slip cage below said slip cone, cooperating latch elements arranged on the mandrel and the slip cage for initially securing said mandrel against downward movement rela- .tive to said slip cage, means carried by the mandrel operable by reciprocative longitudinal movement of the mandrel relative to the slip cage to release said latch elements to thereby release said mandrel for said downward movement whereby to move said slip cone into expansive engagement with said slips, additional cooperating latch elements arranged between the mandrel and the packer body to initially secure the mandrel against downward movement relative to the packer body and releasable by relative longitudinal movement between the packer body and said slip cone produced by engagement of the latter with the slips whereby to free said mandrel for downward movement relative to the packer body, latch means of the straight-pull release type mounted on the mandrel above the packer body for latching the mandrel thereto upon completion of said downward movement of the mandrel relative to the packer body, and seal packing positioned on the mandrel to seal between the latter and the packer body upon said completion of said last-mentioned downward movement.

3. In a well packer of the straight-set type, a tubular mandrel connectible to an operating pipe string, a tubular packer body slidably mounted about the mandrel, an annular radially expansible seal element mounted about the packer body having its upper end :fixedly secured to the body and its lower end free for relative longitudinal movement, a slip cone carried by said lower end of said seal element for said movement therewith, a slip cage slidably mounted on the mandrel below the packer body and carrying means for frictionally engaging a surrounding well wall, radially movable wall-gripping slips mounted on the slip cage below said slip cone, cooperating latch elements arranged on the mandrel and the slip cage for initially securing said mandrel against downward movement relative to said slip cage, means carried by the mandrel operable by reciprocative longitudinal movement of the mandrel relative to the slip cage to release said latch elements to thereby release said mandrel for said downward movement whereby to move said slip cone into expansive engagement with said slips, additional cooperating latch elements arranged between the mandrel and the packer :body initially held in engagement by said slip cone to initially secure the mandrel against downward movement relative to the packer body and releasable by relative longitudinal movement between the packer body and said slip cone produced by engagement of the latter with the slips whereby to free said mandrel for downward movement relative to the packer body, latch means of the straight-pull release type mounted on the mandrel above the packer body for latching the mandrel thereto upon completion of said downward movement of the mandrel relative to the packer body, and seal packing positioned on the mandrel to seal between the latter and the packer body upon said completion of said last-mentioned downward movement.

4. In a well packer according to claim 3, wherein said additional latch means includes a latching groove in the exterior of the mandrel, and a plurality of lug members mounted on said packer body for radial movement into and out of latching engagement with said latching groove.

5. In a well packer of the straight-set type, a tubular mandrel connectible to an operating pipe string, a tubular packer body slidably mounted about the mandrel, an annular radially expansible sealelement mounted about the packer body having its upper end fixedly secured to the body and its lower end free for relative longitudinal movement, a slip cone carried by said lower end of said seal element for said movement therewith, a slip cage slidably mounted on the mandrel below the packer body and carrying means for frictionally engaging a surrounding well wall, radially movable wall-gripping slips mounted on the slip cage below said slip cone, cooperating latch elements arranged on the mandrel and the slip cage for initially securing said mandrel against downward movement relative to said slip cage, means carried by the mandrel op- I erable by reciprocative longitudinal movement of the mandrel relative to the slip cage to release said latch elements to thereby release said mandrel 'for said downward movement whereby to move said slip cone into expansive engagement with said slips, external shoulder means on the mandrel .abuttable by said packer body to limit downward movement of the packer body relative to the mandrel, additional cooperating latch elements arranged between the mandrel and the packer body above said shoulder means initially held in engagement by said slip cone to initially secure the mandrel against downward movement relative to the packer body and releasable by relative retractive movement of said slip cone produced by engagement of the latter with the slips whereby to free said mandrel for downward movement relative to the packer body, top latch means of the straight-pull release type mounted on the mandrel above the packed body for latching the mandrel thereto upon completion of said downward movement of the mandrel relative to the packer body, and seal packing positioned on the mandrel to seal between the latter and the packer body upon said completion of said last-mentioned downward movement.

6. In a well packer according to claim 5, wherein said additional latch means includes a latching groove in the exterior of the mandrel above' said external shoulder means, and a plurality of lug members mounted on said packer body for radial movement into and out oflatchin-g engagement with said latching groove.

7. In a well packer according to claim 5, a plurality of hold-down slip elements mounted in the packer body above said seal element for radial outward movement in response to fluid pressure entering the annular space between the mandrel and the packer body below said seal packing.

References Cited by the Examiner UNITED STATES PATENTS 3/1908 Robinson 166 -138 10/1956 Brown 166--138

Claims (1)

1. IN A WELL PACKER OF THE STRAIGHT-SET TYPE, A TUBULAR MANDREL CONNECTIBLE TO AN OPERATING PIPE STRING, A TUBULAR PACKER BODY SLIDABLY MOUNTED ABOUT THE MANDREL, AN ANNULAR RADIALLY EXPANSIBLE SEAL ELEMENT MOUNTED ABOUT THE PACKER BODY HAVING ITS UPPER END FIXEDLY SECURED TO THE BODY AND ITS LOWER END FREE FOR A RELATIVE LONGITUDINAL MOVEMENT, A SLIP CONE CARRIED BY SAID LOWER END OF SAID SEAL ELEMENT FOR SAID MOVEMENT THEREWITH, A SLIP CAGE SLIDABLY MOUNTED ON THE MANDREL BELOW THE PACKER BODY AND CARRYING MEANS FOR FRICTIONALLY ENGAGING A SURROUNDING WELL WALL, RADIALLY MOVABLE WALL-GRIPPING SLIPS MOUNTED ON THE SLIP CAGE BELOW SAID SLIP CONE, COOPERATING LATCH ELEMENTS ARRANGED ON THE MANDREL AND THE SLIP CAGE FOR INITIALLY SECURING SAID MANDREL AGAINST DOWNWARD MOVEMENT RELATIVE TO SAID SLIP CAGE, MEANS CARRIED BY THE MANDREL OPERABLE BY RECIPROCATIVE LONGITUDINAL MOVEMENT OF THE MANDREL RELATIVE TO THE SLIP CAGE TO RELEASE SAID LATCH ELEMENTS TO THEREBY RELEASE SAID MANDREL FOR SAID DOWNWARD MOVEMENT WHEREBY TO MOVE SAID SLIP CONE INTO EXPANSIVE ENGAGEMENT WITH SAID SLIPS, ADDITIONAL COOPERATING LATCH ELEMENTS ARRANGED BETWEEN THE MANDREL AND THE PACKER BODY TO INITIALLY SECURE THE MANDREL AGAINST DOWNWARD MOVEMENT RELATIVE TO THE PACKER BODY AND RELEASABLE BY RELATIVE LONGITUDINAL MOVEMENT BETWEEN THE PACKER BODY AND SAID SLIP CONE PRODUCED BY ENGAGEMENT OF THE LATTER WITH THE SLIPS WHEREBY TO FREE SAID MANDREL FOR DOWNWARD MOVEMENT RELATIVE TO THE PACKER BODY, AND LATCH MEANS OF THE STRAIGHT-PULL RELEASE TYPE MOUNTED ON THE MANDREL ABOVE THE PACKER BODY FOR LATCHING THE MANDREL THERETO UPON COMPLETION OF SAID DOWNWARD MOVEMENT OF THE MANDREL RELATIVE TO THE PACKER BODY.

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