US2791278A

US2791278A - Packing structures for well devices

Info

Publication number: US2791278A
Application number: US449944A
Authority: US
Inventors: Jr Earnest H Clark
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1954-08-16
Filing date: 1954-08-16
Publication date: 1957-05-07
Anticipated expiration: 1974-05-07

Description

May 7, 1957 E. H. CLARK, JR 2,791,278

PACKING STRUCTURES ECE WELL DEVICES Filed Aug. 16, 1954 2 Sheets-Sheet 1 H6. l. c?. I; 3.

NVENT Mez/w au( 74A/Www TrQEAMU/S May 7, 1957 E. H. CLARK, JR 2,791,278

PACKING STRUCTURES FCR WELL DEVICES Filed Aug. 16, 1954 2 Sheets-#Sheet 2 Ho. 4. I.; 5.

BY www )m .4free/v5 VS l PACKING STRUCTURES FOR WELL DEVICES Earnest H. Clark, Jr., Downey, Calif., assigner to Baker 011 Tools, Inc., Los Angeles, Calif., a corporation of California Application August 16, 1954, Serial No. 449,944

13 Claims. (CIL 1661-204) The present invention relates to packing structures, and

more particularly to packing; structures incorporated inv subsurface well devices which'y are. subjected to high pressures or high temperatures, or to both high pressures and temperatures.

Subsurface well` tools include natural or synthetic rubber packing elements for effecting a seal within a string of well casing, or similar well conduit. Although an eiiicient seal is provided/the rubber material tends to cold flow through adjacent clearance spaces existing. between the well tool and casing, or betweenv parts of the well tool itself, particularly when the tool, is subjected to high pressures or high temperatures, or the combination of high pressures and high temperatures. If suicient rubber flows through such clearance spaces, the packing fails,

lt has been proposed to minimize the aforenoted didiculty by backingV up the rubber packing withl rings of lead or similar pliant, inelastic material, which willV be moved .into bridging position across the clearance space or spaces, and thereby prevent the rubber material from cold flowing thereinto. The use of such` back-up rings ishighly effective, but under extreme conditions of high pressures and temperatures, they, in turn, may be forced intoV the clearance spaces to the extent wherefailure of the packing' structure occurs.

It is, accordingly, an object of the present invention to provide a packing structure which can withstand extremely high pressures and temperatures, of the order encountered in well bores.

Another object of the invention is to provide a relatively simple and inexpensive device for preventing rubber and other packing materials from cold flowing into clearance spaces between a well tool andV well conduit when subjected to very high pressures and temperatures, of the order present in certain Well bores.

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

Referring to the drawings:

Figure 1 is a longitudinal sectional view of a well packer embodying the invention, with its 4parts in retracted posi,- tion for lowering in a well casing;

Fig. 2 is a view similar to Fig. l, with portions of the packer expanded against' the well casing;

Fig. 3 is a view similar to Fig. i, disclosing, the packer anchored in packed-oil condition` within the well casing;

Fig. 4 is an enlarged` fragmentary longitudinal sectionthrough a portion of the Well packer shownin Fig. l;

Fig. 5 is a fragmentary longitudinal section through a portion of the well packer, as disclosedin Fig. 3.

A well packer A is disclosed in Fig. 1 as being coupled` States Patentr O ICC to the end of' a string of tubing B, or the like, with parts of the well4 packer in retracted position to permit its freedom of movement downwardly through a casing C to the' desired setting point. The packer includes a main body 10 carrying a set of upper 'segmental slips 11 disposed adjacent a transverse abutment 12 secured on the upper end of the body, and adapted to be moved into engagement with the casing CV by an upper frusto-conical expander 13 initially retained in retracted position by one or more shear screws 14 attaching it to the main body. The upper slips 11 are similarly lretained in retracted position by respective shearscrews 15,16 'securing them to the expander 13 and body 10.` A lower setof segmental slips 17 is held initially in retracted position and attachedk to the main body 10 by shear screws 18k and to a lower frusto-conical expander 19 through another set of shear screws 20, this lattery expander being held initially in ineffective position by suitable shear screws 21 attaching it to the body. The upperA sets of screws 1d, 1S, 16 have a lower shear value than the lower sets 1S, Ztl, 21, to permit prior outward expansion of the upper. set of slips 11 into anchoring engagement with the well casing C.

A packing structure 22' is positioned between and suitablyv associated with the confronting portions of the frustoconical expanders 13; 19. This packing structure includes a packing sleeve 23 of synthetic or natural rubber initially disposed in retracted position. The sleeve 23 is provided `with a central portion 24 adapted to be expanded outwardly into sealingl engagement with the wall of the Iwel-l casing C and with reduced diameter, generally cylindrical end portions 25"', each of which is disposed within an annular recess 26 in an expander. T he outer surface 27 of. the cylindrical end portion engages the cylindrical inner wall 28 defining the recess, the terminal portion 29 of the packing sleeve engaging an end shoulder 30 detining the recess. The inner surface 31 of the packing 23 engages the periphery of the body 10', the end portions 25 of' the packing sleeve being provided with annular lip seals 32 facing toward one another and Isealingly engaging the periphery of the body 14)- to prevent leakage of fiuid from the interior of the packing 23 to its exterior. Such fluid, as described hereinbelow, can pass from the inner central passage 33 inthe body, through one or more lateral ports 34 in the body, to the interior of the packing 23.

A valve assembly housing 35 is threadedly secured to the lower end of the packer body 10. T hishousing contains a tripping ball seat 36 initially secured to it by a shear screw 37.- The seat has an upstanding arm 38 integral therewith initially engaging a buoyant back pressure ball valve element 39 to hold. it in ineffective position against the interior of the housing and thereby prevent its upward movement into seating engagement with a valve seat 401 provided at the lower end of the main body 1t) and surrounding the central passage 33 through the body. Removal of the retaining arm 38 will permit the ball 39 to move upwardly into engagement w-ith its companion valve seat 40, whenever upward or reverse flow of fluid throughthe body passage 33 tends to occur.

The packer A is run into the casing C by means of the tubing string B attached to its body 19, to the desired setting point, and circulation is established therethrough to-remove any undesired foreign matter in the well casing. Thereafter, atripping ball 41 is lowered or pumped down through the tubing 13 andthe body passage 33 into seating engagement with the tripping ball seat 36, which permits the pressure of the fluid within the tubing string and the packer body tobe increased, this uid under pressure passingV laterally outward through the ports 34 in the body to the interior of the packing sleeve 23'. When sufiicient pressure is imposed* on the uid, it will inflate the packing sleeve outwardly against the well casing, as disclosed in Fig. 2, and will then disrupt thc upper sets of

shear screws

14, 15, 16, sliding the upper expander 13 in an upward direction along the body 10 to move the upper slips 11 against the abutment 12 and then laterally outward into gripping engagement with the well casing C.

After the upper slips 13 have thus been anchored in the well casing, the pressure of the fluid in the tubing string B and the packer body 10 may be increased to a further extent, to disrupt the shear screw 37 holding the tripping ball seat 36 to the valve housing 35 and eject this seat, together with its upstanding arm 38 entirely from the housing which frees the back pressure ball valve element 39 and allows it to move upwardly into engagement with its companion seat 40, whenever reverse flow of fluid through the well packer tends to occur.

An upwardly directed pull or strain may now be taken on the tubing string B and the packer body 10. Since the upper set of slips 11 prevents the upper expander 13 from moving upwardly to any further extent, such upward strain or movement on the packer body will move the lower expander 19 and lower slips 17 toward the upper expander 13, foreshortening and compressing the packing sleeve 23 and expanding it outwardly into firm seal-v ing engagement with the wall of the well casing C and the exterior of the main body 10. A continuation of the upward strain will effect shearing of the

screws

21, 18, 20, holding the lower expander 19 and slips 17 to the body 10 and the slips to the expander, and will cause the lower portion of the body 10 and valve housing 35 to engage the lower slips 17, sliding them upwardly along the lower expander 19 and radially outward into anchoring engagement with the wall of the well casing C. The various slips, expanders and packing sleeves are held in their respective expanded positions by an annular split ratchet ring 42 contained within a groove 43 in the upper expander 13 and engaging downwardly facing circular ratchet teeth 44 formed on the exterior of the body. The packer A is now fully anchored in packedolf condition within the well casing C, as disclosed in Fig. 3.

Fluent substances under pressure may now be pumped down the tubing string B and out through the well packer A to perform a desired function in the well bore. As an example, cement slurry may be pumped under very high pressure through the well packer and into a formation surrounding the well casing C. When the well packer is subjected to comparatively high pressures, which may be of the order of 7,000 or 8,000 p. s. i., and is subjected to comparatively high temperatures encountered in the well bore, such as 300 to 350 degrees F., the rubber packing material may tend to be displaced by such pressures through the annular clearance spaces 45 that exist between the

expanders

13, 19 and the wall of the well casing C and also through the clearance spaces between the expanders and the packer body- 10 itself. The latter clearance spaces are relatively small in extent and may ordinarily be insufficient to allow any substantial cold owing of the rubber packing material thereinto. However, the annular clearance spaces 45 between the

expanders

13, 19 and the wall of the well casing are substantial, and offer a comparatively large area through which the rubber packing material can be squeezed. In the specific form of the invention disclosed in the drawings, the rubber packing material is prevented from cold owing into the larger annular clearance spaces 45 between the expanders and the wall of the well casing, although it will be evident that the invention is useful in preventing cold flowing of the rubber packing material through clearance spaces in general.

As specifically illustrated, each

expander

13, 19 actually constitutes a retainer or abutment for the packing structure 22, since it tends to prevent endwise movement of the packing structure. The main intermediate portion 24 of the rubber packing sleeve 23 has an external diameter substantially greater than the end cylindrical portions 25 of the packing sleeve. There is an inclined frusto-conical surface 46 between the exterior of each cylindrical portion 25 and the periphery of the main central portion 24 of the packing sleeve. This inclined surface 46 is spaced longitudinally away from the confronting end 47, 4S of the expander or

abutment

13, 19, the packing sleeve defining an annular external groove 49 with the adjacent abutment, in which elements 50, S1 are disposed for preventing cold flow of the rubber packing material through the annular clearance space 45. Actually, the upper and lower portions of 'the packing sleeve 23 and the adjacent expanders or

abutments

13, 19 are alike, so that an explanation of one expander and one side of the packing structure will sutlice for both. It is sutlicient to state 'that the ends of the packing sleeve and of the adjacent portions of the abutments are identical, being reversely disposed.

Disposed within the groove 49 provided between the upper abutment 13 and 'the packing sleeve 23 is an annulus 50 of pliant, inelastic material, such as lead, which has an inner cylindrical surface 52 embracing the periphery of the cylindrical portion 25 of the packing sleeve, an outer cylindrical surface 53 which is adapted to be moved outwardly into sealing engagement with the wall of the well casing C, and an intervening lower tapered or inclined surface 54 which is companion to and engages the corresponding inclined surface 46 on the packing sleeve 23. The deformable annulus 50 is also provided with an upper inclined surface 55, which inclines in a downward and outward direction with respect to the associated abutment 13, and this inclined surface engages a companion internal inclined surface 56 on a generally frusto-conical ring 51, which is substantially thinner than 'the lead ring 50 and which is made of -a malleable material, such as aluminum, malleable iron, wrought iron, mild steel, copper, brass or bronze.

The frusto-conical ring 51 has an upper end portion 57 tting within a recess 58 in the lower outer portion of the adjacent abutment 13, and it also has an outer inclined surface 59 which may be generally parallel to the inner inclined surface 56, although not necessarily so, that initially tapers in a downward and laterally outward direction with respect to an adjacent transverse shoulder 48 formed at the lower portion of the upper expander, there being initially a substantial space between the abutment shoulder 48 and the outer surface 59 of the thin malleable ring. The outer surface of the ring 51, as well as the outer surface 55 of the lead ring 50 which it engages, are initially in retracted position, removed from engagement with the wall of the well casing C to essentially the same extent as the central sealing portion 24 of the packing sleeve 23 itself.

It is to be noted that rubber packing material is disposed within the pliant, inelastic or lead ring 50 and that this lead ring is disposed within the malleable outer ring 51. This malleable outer ring 51 may be stretched and expanded in an outward direction with deformation, but it is not as readily deformable as the lead, or similar material, of which the pliant, inelastic ring 50 is formed. The outer ring 51 resists deformation to a far greater extent than the lead inner ring 50 and is adapted to bc stretched outwardly into engagement with the wall of the well casing C, in order to bridge the annular clearance space 45 between the abutment 13 and the casing, and prevent cold flowing of the inner lead ring 50 and the rubber packing 23 thereinto.

When an upward strain is taken on the tubing string B and the packer body 10, for the purpose of foresholtening the packing sleeve 23 and expanding it into sealing engagement with the wall of the well casing C, the upward force on the rubber will act through the inclined surfaces 54 of the lead vpackingringsA 50 to stretch and expand the latter inan outward direction'toward the well casing.A As

such stretching and expansion of each lead ring occurs, it acts upon the frusto-conical ring l to tend to stretch and expand it in an outward direction, shifting it about its inner contact region 57 with the abutment 13 and stretching it outwardly so that the outer vring 51 engages the abutment shoulder 48 and also the wall of the well casing C. The rubber packing material will stretch the lead sealing ring 50 outwardly against the wall of the well casing before sufficient compression is exerted on the packing sleeve 23 tending to cause it to How around the ex terior of the lead seal ring. Similarly, the outer malleable ring S1 is expanded outwardly into its bridging position across the clearance space 45 between the abutment 13 and the well casing C before the lead sealing material is subjected to sufficient pressure as to cause it to flow around the exterior of the malleable ring. Accordingly, the rubber packing 23 is prevented from moving around the exterior of the lead ring 50, the latter also being prevented from moving around the exterior of the malleable ring 51, which will insure that the lead ring 50 will function to prevent cold ow ofthe rubber member 23 past it and the malleable ring 51 will act to insure cold flow of the lead material 50 past it.

The lead ring is more ductile than the malleable ring and will be expanded against the casing more readily 4by the rubber packing sleeve. If the lead ring 50 were omitted and the malleable ring 51 only were'used to back up the rubber packing material 23, its lesser ductility, as compared to lead, might cause the rubber to flow around it before it was expanded outwardly into engagement with the well casing. Thus, the use of lead as an intervening material between the rubber sleeve 23 and the malleable outer ring 51 offers several advantages. panded against the casing by the rubber sleeve 23, with assurance that the rubber lwill not flow therearound, and, additionally, it functions as a very effective metallic sealing or packing material, being deformed appropriately into intimate sealing Contact with the wall of the well casing C. The malleable outer ring 51 will not necessarily conform to irregularities and imperfections in the surface of the casing wall. However, despite the fact that the outer malleable ring 51 will not deform to as great an extent as the lead ring, it is still urged outwardly against the casing by high pressure, and the fact that it does not deform causes it to act more effectively as a bridge across the annular clearance space 45. The high pressures encountered in the well bore, in combination with high temperatures therein, will not produce bulging of the outer ring 51 into the clearance space 45 that might produce its failure, as might occur when lead back-up rings alone are used.

It is, accordingly, apparent that a packing structure has been provided which will insure retention of the rubber sealing material at its intended position whereby its main portion 24 is effective to seal against the wall of the well casing C, as well as against the periphery of the packer body 10. Despite the presence of high pressures and temperatures in the well casing to which the packing sleeve is subjected, it cannot flow from its intended sealing region through the clearance spaces 45 existing between the well casing C and the upper and lower expanders or

abutments

13, 19.

The inventor claims;

l. In a packing structure: a non-metallic packing adapted to engage and seal against a companion member; abutment means adjacent said packing and adapted to provide a clearance space with the companion member; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be forced by said packing against the companion member to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic malleable annulus between and engageable with said abutment means and deformable annulus to be forced by said deformable annulus against the companion member to bridge the clearance space and It will be exprevent passage of the deformable annulus thereinto; said malleable lannulus being substantially 'less deformable than said deformable annulus.

2. In a packing structure: a non-metallic packing adapted to engage and seal against a confining enclosure; abutment means adjacent said packing and adapted to provide a clearance space with the enclosure; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be expanded laterally outward by said packing against the enclosure to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic malleable annulus between and engageable with said abutment means and deformable annulus to be expanded and stretched laterally outward by said deformable annulus into a malleable annulus of increased radial width against the enclosure to bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable. annulus.

3. In a packing structure: a non-metallic packing adapted to engage and seal against a companion member; abutment means adjacent said packing and adapted to provide a clearance space with the companion member; a pliant, inelastic deformable annulus adjacent said abutment means and having an inclined surface engaging a companion inclined surface on said packing to be forced by said packing laterally against the companion member to bridge the clearance space and prevent passage of the packing thereinto when said packing moves toward said abutment means; and a pliant, inelastic malleable annulus between said abutment means and deformable annulus, said malleable annulus and deformable annulus having coengaging inclined surfaces to cause said deformable annulus to force said malleable annulus laterally against the companion member to bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleableannulus being substantially less deformable than said deformable annulus.

4. In a packing structure: a non-metallic packing adapted to engage and seal against a confining enclosure; abutment means adjacent said packing and adapted to provide a clearance space with the enclosure; a pliant, inelastic deformable annulus adjacent said abutment means, said annulus and packing having coengaging Surfaces inclined outwardly in a direction leading away from said abutment means to cause said packing to force said deformable annulus laterally outward against the enclosure to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic malleable annulus between and engageable with said abutment means and deformable annulus, said deformable annulus and malleable annulus having coengaging surfaces inclined in the same general direction as said other coengaging surfaces in order that said deformable annulus will force and stretch said malleable annulus laterally outward into a malleable annulus of increased radial width and against the enclosure to bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable annulus.

5. In a packing structure for a well packer: a nonmetallic packing adapted to engage the wall of a well casing; abutment means adjacent said packing and adapted to provide a clearance space with the casing; said packing being provided with a circumferential recess adjacent said abutment means to provide a groove between said packing and said abutment means; a pliant, inelastic deformable annulus in said groove encircling and embracing said packing to prevent its passage into the clearance space; and a pliant, inelastic malleable annulus in said groove between and engageable with said abutment means and deformable annulus to be forced and stretched by said deformable annulus into a malleable annulus of increased radial Width laterally against the casing to 7 bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable annulus.

6. In a packing structure as defined in claim 1; v vherein said deformable annulus is a lead member and said malleable annulus is a ferrous member.

7. In a packing structure as defined in claim 5; wherein said deformable annulus is a lead member and said malleable annulus is a ferrous member.

8. In a packing structure as defined in claim 1; wherein said deformable annulus is a lead member and said malleable annulus is an aluminum member. v

9. In a packing structure as defined in claim 5; wherein said deformable annulus is a lead member and said malleable annulus is an aluminum member.

l0. In a packing structure: a non-metallic packing adapted to engage and seal against a companion member; abutment means adjacent said packing and adapted to provide a clearance space with the companion member; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be forced by said packing against said companion member to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic malleable annulus between said abutment means and deformable annulus, said malleable annulus engaging said deformable annulus and having one of its peripheral portions only initially engaging said abutment means, whereby said deformable annulus pivots said malleable annulus about said abutment means into full engagement with said abutment means and against the companion member to bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable annulus.

ll. In a packing structure: a non-metallic packing adapted to engage and seal against a companion member; abutment means adjacent said packing and adapted to provide a clearance space with the companion member; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be forced by said packing against the companion member to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic thin frusto-conical malleable annulus between said abutment means and deformable annulus, said thin annulus engaging said deformable annulus and having one of its peripheral portions only initially engaging said abutment means, whereby said deformable annulus pivots said thin annulus about said abutment means into full engagement with said abutment means and against the companion member to bridge the clearance space and prevent passage of the deformable annulus thereinto; said thin annulus being substantially less deformable than said deformable annulus.

12. In a packing structure: a non-metallic packing adapted to engage and seal against a confining enclosure; abutment means adjacent said packing and adapted to provide a clearance space with the enclosure; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be expanded outwardly by said packing against the enclosure to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic malleable annulus between said abutment means and deformable annulus, said malleable annulus engaging said deformable annulus and having its inner peripheral portion only initially engaging said abutment means, whereby said deformable annulus pivots said malleable annulus about said abutment means and stretches it into full engagement with said abutment means and against the confining enclosure to bridge the clearance space and prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable annulus.

13. In a packing structure: a non-metallic packing adapted to engage and seal against a confining enclosure; abutment means adjacent said packing and adapted to provide a clearance space with the enclosure; a pliant, inelastic deformable annulus adjacent said abutment means and engaging said packing to be expanded outwardly by said packing against the enclosure to bridge the clearance space and prevent passage of the packing thereinto; and a pliant, inelastic thin frusto-conical malleable annulus between said abutment means and deformable annulus, said malleable annulus engaging said deformable annulus and having its inner peripheral portion only initially engaging said abutment means, whereby said deformable annulus pivots said malleable annulus about said abutment means and stretches said malleable annulus into full engagement with said abutment means and against the confining enclosure to bridge the clearance space to prevent passage of the deformable annulus thereinto; said malleable annulus being substantially less deformable than said deformable annulus.

References Cited in the file of this patent UNITED STATES PATENTS 2,695,068 Baker et al. Nov. 23, 1954