US2808889A - Well packer - Google Patents

Description

HARRY E. scHwEGMAN BY w1! 9Wd ATTORNEY WELL PACKER Filed Aug. 2, 1954 Oct 8, 1957 o. MoRRlsET-r ET AL United States Patent WELL PACKER O. L. Morrisett and Harry E. Schwegman, Duncan, Okla., assignors to Halliburton Oil Well Cementing Company, Duncan, Okla.

Application August 2, 1954, Serial No. 447,122

S Claims. (Cl. 166-190) This invention relates to apparatus for use in oil wells and the like, and more particularly to well packers of the type which are adapted to be lowered in unexpanded position into a well bore and then expanded into sealing engagement with a wall of the Well bore.

Well packers of -the type described are used for various purposes in connection with oil and gas wells and commonly include a cylindrical sleeve mounted about a mandrel or cylindrical body, which sleeve is made of a resilient material, such as natural or synthetic rubber, and is adapted to be expanded against the side of the well bore in response to longitudinal compression. It is the purpose of the packer to provide a huid-tight seal across the well bore.

In the past, however, certain diiiiculties have been attendant upon the use of such type packers. Frequently, the maintenance of a fluid-tight seal across which is likely to be found considerable pressure differentials, such as are often present in wells, requires very tight engagement by the packer with the wall of the well bore. To this purpose, the sleeve of the packer must be made of relatively highly expansible material, but it is found, and particularly at the high temperatures prevailing in deep wells, that the resilient material of which the packer is composed tends to creep or extrude .through small crevices or spaces, acting much as does a liquid. The shoes ordinarily provided at the top and at the bottom of the sleeve, which are of a diameter sufficiently small to prevent the possibility of their being stuck in the well bore, are usually of little effect in preventing the resilient sleeve material from extending therebeyond as the packer is set.

The aforesaid tendency of the sleeve material to ow in the presence of high temperatures and high pressunes is often referred to as cold-flowing, and presents the likelihood that the seal intended by the packer will fail. Additionally, the effect may prevent the sleeve from being returned to its unexpanded position, if such is desired. Again, the useful life of the sleeve is materially reduced, and attempted removal of the packer from the well will result in a torn or ruptured, and hence unusable, sleeve. Yet again, the aforesaid cold-flowing of the sleeve material'may interfere with or obstruct the action of the particular tool with which the packer is associated.

Heretofcre various proposals have been made for overcoming the foregoing diiculties, but the prevention of the aforesaid extrusion or cold-flowing has required either the use of relatively complex and expensive devices, or the use of devices having relatively short life, or especially designed packers suited only for use under certain conditions.

It is the general object of this invention to provide an improved well packer adapted to maintain a reliable seal across the wall of a well bore.

It is another object of this invention to provide such a well packer capable of performing the aforesaid function yet having a relatively lengthy, useful life.

`It is -a .further object of this invention to provide an improved well packer incorporating means adapting the packer for use with high pressures and temperatures commonly prevailing in deep oil and gas wells.

It is another object of this invention to provide an improved well packer having means for substantially preventing objectionable extrusion or cold-flowing of the packing material. i

it is yet another object of this invention to provide an improved well packer wherein means are incorporated to restrict and retain the packing material from flowing from its proper disposition within the well bore.

It is another object of this invention to provide an irnproved well packer having means for preventing the spe` cic owing of the packing material between the wall of the well bore and the packer-encompassing shoes.

The foregoing and other objects, features and advantages of the invention will be more apparent from the following description when read in connection with the accompanying drawings in which similar numerals refer to similar parts and wherein:

Figure 1 shows a side elevational view of a formation testing assembly positioned in a well bore, the lassembly including a well packer constructed in accordance with the instant invention and shown in an unexpanded position within the well bore.

Figure 2 shows a longitudinal sectional View of a portion of the assembly of Figure l.

Figure 3 shows a longitudinal sectional view similar to that of Figure 2 but demonstrates the Well packer in a substantially, fully expanded position within the well bore.

ln essence, the invention of thisv application consists in the concept of providing a well packer 1t) comprising a packing sleeve 26 adapted to be expanded into sealing engagement with the Wall of the well bore 14 through longitudinal compressive force and including at one or the other of its ends, or both, the provision of a resilient restraining ring 32 separated from the packing sleeve by means interposed therebetween, such as the collar or separating means 30. lt further consists in the concept of providing means for limiting the compression of the restraining :ring 32, whereby the maximum outward expansion of said ring may, if desired, be predetermined, and it further consists in the concept of encompassing said rcstraining ring within longitudinally acting compressive 'and positioning members, whereby upon expansion said restraining ring accommodates itself to the most efficient disposition for preventing cold-flowing of the material of the packing sleeve 26. l,

Referring now to the specific embodiment of the .invention shown in the drawings, it will be noted that the well packer is presented in association with a testing assembly 12, but it is to be understood that the invention herein set forth is applicable to well packers generally wh is utilized an expansible, resilient sleeve expanded through :compressive longitudinal forces.

The testing assembly 12 is shown positioned within a well bore 14 in the vicinity of a formation 16 to be tested.-

2li connected tothe drill pipe 18, a pipe or tubing 22.

coupling the lower end of the tool Ztl to the upper end of: the packer 10, and a perforated anchor pipe 2li extending downwardly from the packer 10. The pipe 24- is shown in Figure l with its lower end resting on the bottom of the well bore 14.

As shown best in Figure 2, the well packer lincludes a resilient Vand expansible packing lsleeve 26 sldably mounted on a central mandrel 28 and a restraining ring 32 mounted on the mandrel 28 in longitudinally adjacent'relation to the sleeve 26. The restraining ring 32 is likewise resilient and expansible and is mounted for limited. compression and expansion in Iresponse to the same force which isV applied to compress and expand the sleeve 26. A collar 30 is providedy interposed between the sleeveV 26 and .the'riug 32, said collar having a cylindrical portion 72 disposed circumferentially about the mandrel 28 and having extending outwardly from` the cylindrical portion 72 a :flange 74 -adjacent to and preferably abutting the lower or free end S8 of the sleeve 26.

Any of variousV suitable means may be employed for compressing and expanding the sleeve 26 and the ring 32. Abutme'nt means may comprise an upper shoe' 34' and a lower shoe '70. The upper shoe 34 is shown as sli'dable and may be mounted for relative longitudinal movement with respect tothe mandrel 28 and may be movable downwardly along the mandrel 28 to compress and expand the sleeve 26 and the ring 32.

As illustrated, the sliding shoe 34 is threadedly or otherwise secured to the lower portion of `a hollow mandrel guide 36. The pipe or tubing 22 extending downwardly from the testing tool 20 (shown in Figure l) extends into and is threadedly or otherwise secured to the upper portion of the guide 36. The mandrel 28 extends into the lower portion of the guide 36, and has an upper portion or head 38 slidably positioned in the guide 36, the arrangement being such that as the sliding shoe 34 is moved downwardly along the mandrel 28, the mandrel head 38 is moved relatively upward within the guide 36.

The mandrel 28 has its lower end coupled by suitable means, such as by meansV of a hollow threaded adapter 40, to the upper end of the anchor pipe 24. When the lower end of the anchor pipe 24 is resting against the bottom of the well bore'14 (see Figure 1), the mand-rel 28 is then supported against relative downward movement along the well bore 14. The sliding shoe 34 may then be caused to move downwardly along the mandrel 28 by setting down or lowering the drill pipe 18 connected to the testing tool 20.

The mandrel guide 36 preferably has in its inner wall 42 Ia lower abutment 44 adapted to engage the mandrel head 38 and thus limit relative downward movement of the mandrel 28 with respect to the guide 36. When the guide 36 is connected, as shown, to the pipe 22, the lower end of the pipe 22 provides within the guide 36 an upper abutment 46 which limits relative upward movement of the mandrel 28 with respect to the guide 36.

lf desired, longitudinally extending grooves 48 may be provided in the inner wall 42 of the guide 36 and the mandrel head 38 may be provided with lateral protuber- 'ances 50 which engage the grooves 48 and support the mandrel 28 against relative rotational movement with respect to the guide 36. The grooves 48 may extend from the lower abutment 44 upwardly along the wall 42 to the upper -abutment 46 and thus provide a. track along which the mandrel head 38 is movable within the guide 36.

If desired, yan annular recess S2 adapted to receive the head 38 may be provided in the inner wall 42 below the upper abutment 46. When the head 38 is moved 'relatively upward within the guide 36Y suiciently to be positioned within the recess 52, the guide 36 may then be rotated with respect to the mandrel 28, if desired, to lock the mandrel 28 in an upper position with respect to the guide 36 or for other purposes.

As illustrated, the packing sleeve 26 encireles the mandrel 28 below the sliding shoeV 34. The sleeve 26 has an upper end portion 54 fitted and preferably attached to the shoe 34 and has a skirt portion 56 extending downwardly from the shoe 34. The skirt portion 56 terminates intermediate the ends of the mandrel 28 in the `free endr58 adjacent to and preferably abutting the collar 30.

A-ny of various suitable meausmay be employedY for tting and preferably attaching the sleeve 26 to the shoe 34. Forexa'rnple, the upper'end' portion" 54 ofthe sleeve 26 may be closely fitted within a downwardly facing annular recess 60 provided in the shoe 34. For the purpose of attaching the end portion 54 to the shoe 34 an inner annular recess 62 may be provided in the shoe 34 above the recess 60 and a ring 64 made of metal or the like may be embedded in the sleeve 26 a suitable distance below the shoe' 34. The ring 64 preferably encircles the mandrel. 28 and may be connected to the shoe 34 by screw bolts 66 or the' like, which. extend through perforations suitably provided between the recesses 60 and 62 in the shoe 34- and in the upper portion of the sleeve 26.

As hereinabove stated, below the sleeve 26 is disposed the collar 30, and below the collar 30 is provided a bottom shoe '70 secured to or integral with the mandrel 28. The ring 32, which encircles the cylindrical portion 72 of the collar, has its upper end 76 abutting the lower. surface 78 of the flange 74 of collar 30 and has its lower end 80 abutting the upper surface 82 of the bottom` shoe 70. The collar 30 is slidable on the mandrel 28, and the length of` the cylindrical portion 72 of said collar is such that the end 84 ofsaidV cylindrical portion is normally disposeda slight distance above the end 85.0fV the adapter 40 when the restraining ring 32 is unexpanded. Thus is provided a shoulder means lXed with Vrespect to the body .or mandrel 28 which isengageable by the end of the cylindrical portion 72of the collar' 3l) to limit compression, and therefore expansion, ofthe Vring 32. Y

In operation, the testing assembly 12 or other tool with which the well packer 10 is associated is lowered on the drill pipe 1'8 int'o the well bore 14'to a desired depth in the vicinityV ofthe formation 16. In this embodiment, it is desirable that the wellV packer 10 be immediately above the formation. 1*'6,` andinorder to accomplish this the length of anchor pipe 24 is selected so that when the lower end of said pipe reaches the bottom of the well bore 1'4 the well. packer isv so positioned.

Figures l andV 2 show the testing assembly as it is lowered to the bottom in-the well bore and the parts are therein shown occupying their respective positions during this descent. The well packer 10 is unexpanded and the upper or sliding-shoe 34 is in its uppermost position with respect to the mandrel 28, said mandrel being carried by the mandrelguide 36 with the lower abutment 44Y supporting the mandrel head 38 against relative downward movementv with respect to the mandrel guide and the sliding shoe 34 secured thereto.

Expansion of the well packer 10 is accomplished by further lowering of the drill pipe 18 after the lower end of the anchor pipe 24 has reached the bottom of the wellY bore. This causes a force to be applied to the mandrel` guide 36 through the testing tool 20 and pipe 22. Such'force moves'the mandrel guide 36 and sliding shoe 34 secured theretodownwardly with respect to the mandrel 28, which'is-at that time supported by the anchor pipe 24 againstv further downward movement along the Well bore 14.

As best shown in Figure 3, as the sliding shoe 34 is moved downwardly along the mandrel 28, a force is applied by theshoe 34 to the'upper end portion 54 of the sleeve 26; ThisA force tends to move the slidably mounted sleeve 26 downwardly 'along the mandrel 28 and forces the lower or free end 58 of the sleeve 26 down wardly against the collar 30. Said collar 30, whichis slidably mounted'on the mandrel 28,- in turn moves down'- wardly along said mandrel, and since the bottom shoe 70 is Vsecured to or integral withA the 'adapter 40, which` in turn is secured to the anchor pipe 24,v the sleeve 26 is compressed between the sliding shoev 34" and the collar 30 and the restraining, ring 32fin turn' compressed between the said collar. 30` and the bottom shoe 70. Such com` pression results'in the expans'ii'mz of the sleeve 26v into sealing engagement..with.\ the wallof the welll bore and at the same time results in the expansion of the restraining ring 32.

Upon the application of sufficient force to drill pipe 18, it may be seen that the lower end 84 of the cylindrical portion 72 of the collar 30 will move into engagement with the end 85 of the adapter riti, whereby further compression, and consequently expansion, of the restraining ring 32 between collar 39 and bottom shoe 70 is prevented. This does not, however, prevent further compression and expansion of the sleeve 26, said further compression being only limited by the travel of the mandrel head 38 to abutting disposition with the upper abutment 46 atthe lower end of the pipe 22.

Thus the sleeve 26, which is composed of relatively highly expansible material, is expanded tightly against the wall of the well bore and providesV a seal thereagainst while the ring 32 adjacent the sleeve functions primarily not as a sealing means but rather as a restraining means to prevent cold-owing of the sleeve 26. To this effect it will be noted that the expansion of the restraining ring 32 is not dependent upon the sleeve 26 itself, the sleeve 26 so far as the restraining ring 32 is concerned being but a force transmitting medium whereby the collar 3i! evenly expands the ring. This results in an avoidance of lack of overall expansion which might be the case were such expansion to depend upon direct action of the highly resilient free end 5S upon the ring and which might permit cold-owing of the sleeve 26.

Further, since the ring 32 is not primarily designed for the purpose of a seal, but on the contrary is designed for the purpose of restraining the resilient material of the sleeve 26, and since it is desirable that the material of the ring 32 itself not be caused to cold-ow, it will be noted that compression of the said ring is limited by virtue of the abutment of the lower end S4 of the collar 3@ and the end 85 of the adapter 4i). Thus may the expansion of the ring 32 be predetermined for maximum restraining effect. In this regard, it is desirable that the material of the ring 32 be relatively less expansible than the inaterial of the sleeve 26.

Also, since the flange 74 of the collar 30 is interposed between the lower or free end S8 of the sleeve 26 and the upper end 76 of the ring 32, it will be noted that the flange 74 functions as a positioning member whereby upon expansion the ring 32 accommodates itself to an efficient disposition for preventing cold-flowing of the material of the sleeve 26. To this end, the lower surface 78 of the ange 74 and the abutting upper end 76 of the ring 32 may, if desired, be tapered outwardly and upwardly so that upon compression the ring 32 not only expands outwardly but also moves upwardly to some extent toward the portion of the sleeve 26 which tends to creep or extrude beyond the ange 74. Likewise, if desired, the upper surface 82 of the bottom shoe 7d and the abutting lower end 80 of the ring 32 may also be tapered outwardly and upwardly so as to assist Vin the positioning of the ring 32.

Upon completion of the testing operation, or the particular other function for which the packer is utilized in association with another tool, it will usually be desirable to release the packer. This is accomplished in the instant embodiment by release of the force applied to the sleeve 26 and ring 32 through release of the force applied to the sliding shoe 34 through the mandrel guide 36, the pipe 22, the testing tool 20, and the drill pipe l. In the event that the drill pipe has been rotated so that the mandrel head 38 is locked within the recess 52, it is, of course, necessary to rotate the drill pipe to release said mandrel head.

While there has been described what is at present considered a preferred embodiment of the present invention, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the essence of the invention, and

particularly that the invention herein presented is adapted to various types and kinds of tools other than testing assemblies. It is intended to Vcover herein all such modications and changes as come within the true spirit and scope of the appended claims.

We claim:

1. In a well packer: a body; a resilientand expansible packing sleeve around said body; a resilient and expansible restraining ring adjacent an end of said sleeve, said ring being relatively less expansible than said sleeve; packing sleeve abutment means and restraining ring abutment means at each non-adjacent end of said sleeve and ring; a collar interposed Vbetween the adjacent ends of said packing sleeve and said restraining ring; means for apply.- ing compressive force to-said abutment means to expand said packing sleeve between said packing sleeve abutment means and said collar and said restraining ring between said collar and said restraining ring abutment means; and shoulder means on said restraining ring abutment means engageable by said collar to limit compression of said restraining ring.

2. In a well packer: a body; a resilient and expansible packing sleeve around said body; a resilient and expansible restraining ring adjacent an end of said sleeve said ring being made of a relatively less expansible material than is used in making said sleeve; packing sleeve abutment means and restraining ring abutment means at each non-adjacent end of said sleeve and ring; separating means interposed between the adjacent ends of said packing sleeve and said restraining ring; means for applying compressive force to said abutment means to expand said packing sleeve between said packing sleeve abutment means and said separating means and said restraining ring between said separating means and said restraining ringlabutment means; and shoulder means on said restraining ring abutment means engageable by said separating means to limit compression of said restraining ring.

3. In a well packer: a body; a resilient and expansible packing sleeve around said body; a resilient and expansible restraining ring adjacent an end of said sleeve, said ring being made of a relatively less expansible material than is used in making said sleeve; packing sleeve abutment means and restraining ring abutment means at each nonadjacent end of said sleeve and ring; a lianged collar interposed between the adjacent ends of said packing sleeve and said restraining ring, said flanged collar being slidable on said body and having a cylindrical portion interposed between said restraining ring and said body; means for applying compressive force to said abutment means to expand said packing sleeve between said packing sleeve abutment means and said flanged collar and said restraining ring between said lianged collar and said restraining ring abutment means; and shoulder means on said restraining ring abutment means engageable by the end of said cylindrical portion to limit compression of said restraining ring. Y

4. In a well packer: a body; a resilient and expansible packing sleeve around said body; a flanged collar slidable on said body and having a cylindrical portion around said body; a resilient and expansible restraining ring around said cylindrical portion, said flanged collar being interposed between said packing sleeve and said restraining ring, and said ring being relatively less expansible than said packing sleeve; shoes at each end of said packing sleeve and said restraining ring, respectively, removed from said anged collar, one of said shoes being slid-` able with respect to said body; means for applying compressive force to said shoes to expand said packing sleeve between one of said shoes and said anged collar and said restraining ring between said anged collar and the other of said shoes; and shoulder means associated with said last mentioned shoe and fixed relative thereto engageable by the end of said cylindrical portion to limit compression of said restraining ring.

l5.. In; a Well packer: a body; aA resilient andexpansible Packing sleeve around said body; aangedeollar slidable on said body and having a zkzylindrieal` portion around said body; a resilient and expansible restraining Aring around said cylindrical portion, said anged collar being interposed between said packing sleeve and said restraining ring, and said ring being made of a relatively less expansible material than is used in making said sleeve; a shoe at the end of said packing sleeve removed from said flanged collar; said shoe being slidable, with respect to said body; a second shoe at the end of said restraining ring removed from said anged collar, said shoe being fixed with respect to said body; means for applying compressive force to said shoes to expand said packing sleeve between said rst shoe and said anged collar and said 8 restraining ring between said second Shoek and Saidy anged collar; and a shoulder associated with said body and iixed relative thereto engageable by the. end of. said cylindrical portion to limitV compression of said restraining ring. Y

References `Cited in the iile ofA thistpatent UNITED STATES PATENTS 1,946,353 Mack Feb. 6, 1934` 1,956,694 Parrish May 1, 1934 2,171,049 Simmons Aug'. 29, 1939 2,207,019 Linville July 9, 1940 2,602,513 Conrad et al July 8, 1952

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