US2368928A

US2368928A - Packing device

Info

Publication number: US2368928A
Application number: US434922A
Authority: US
Inventors: Charles M King
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1942-03-16
Filing date: 1942-03-16
Publication date: 1945-02-06
Anticipated expiration: 1962-02-06

Description

Feb. 6, 1945. K|NG 2,368,928

PACKING DEVICE Filed March 16, 1942 2 Sheets-Sheet 1 [III/[III S l J I GI /4945s .44. ENG,

INVENTOR.

W ATW C. M. KING PACKING DEVICE Feb. 6, 1945.

Filed March 16, 1942 2 Sheets-Sheet 2 CHAPL ES 111. k'M/a,

IN V EN TOR.

A TTORNEY Patented Feb. 6, 1945 PACKING DEVICE Charles M. King, Huntington Park, Calif., as-

signor to Baker Oil Tools, Inc., Vernon, Calif., a corporation of California Application March 16, 1942, Serial No. 434,922

9 Claims.

This invention relates to packings of the flexible and pliable type, and particularly to packings whose supporting members have material clearance with the wall of a confining enclosure. An example of this arrangement is a well packer movable through a string of casing to a particular location where its packing member is sealed off against the casing.

As pointed out in United States Patent No. 2,204,648, the substantial clearance that must be allowed between the supporting or retaining member for a pliable packing and the -wall of a casing provides an open annulus through which the packing member can flow upon being sub jected to high pressures or temperatures within the well casing. Such cold flowing hasbeen prevented by encircling the packing with a lead ring adjacent the supporting member. The ring is initially spaced inwardly from the packing walls, but is capable of deformation or stretching outwardly by the stress induced in the packing into position across the annular space and in contact with the wall of the casing, so as to form a bridge or barrier to the flow of the packing material through this annular space.

Lead and similartypes of pliable and inelastic materials are effective devices' for maintaining the packing at the region where it is to perform its sealing function against the casing walls. However, these materials achieve a permanent deformation or set, and remain in engagement with the casing after having been distorted by the rubber or other pliable packing. Their use is therefore limited, and they cannot be employed eflectively in a well packer of the retrievable type, especially those capable of repeated setting and release without removal from the well casing.

It has been proposed to prevent cold flowing of plastic packing material through the annular space above referred to by providing a flow preventing ring composed of a plurality of small segments encircling and embracing the end of the packing, as described in the application of Reuben C. Baker, Serial No. 374,471, filed January 15, 1941, for Packing devices, now Patent No. 2,295,770, granted September 15, 1942. This segmental ring is expanded outwardly by the packing material to bridge the annular space between the well packer and Wall of the casing, in which position comparatively small spaces exist between adjacent segments of too small an extent to permit flow of packing material therethrough. It is an object of the present invention to prevent cold flowing of plastic packing material around apparatus such as a well packer, without impeding the removability of the apparatus from a set position, by means of a ring composed of a. plurality of segments that separate upon expansion of the packing material without forming a space through which the plastic packing material might tend to flow.

It is a further object of the invention to provide a packing structure specifically designed for use in a well tool, such as a retrievable well packer, in which longitudinal compression ormovement of the packing material assists radial expansion of plastic flow preventing segments into engagement with the wall of the casing;

Still another object of the invention is to employ a packing flow preventer around a packing, which is movable into engagement with a well casing by the expansion of the packing Without leaving intervening spaces through which the packing material might flow, andmovable from engagement with the casing by the packing to its initial position upon retraction of the latter, in order to permit free longitudinal movement of the well packer within the casing after it has been set and sealed therewithin.

This invention has other objects that will become apparent from a consideration of the embodiment shown in the drawings accompanying and forming part of the present specification. This embodiment will now be described in detail, but it is to be understood that such detailed description is not to be taken in a limited sense, since the scope of the invention is best defined by the claims appended hereto.

Referring to the drawings:

Figurel is a combined sectional and elevational view of a portion of a well packer, with its packing elements disclosed in retracted position;

Figure 2 is a view similar to Figure 1, with the packing elements in expanded condition;

Figure 3 is a cross section taken generally along the line 3-3 in Figure 1;

Figure 4 is a cross section taken generally a tubular body ID to which is threaded or otherwise secured a packing actuator I I in the form of a guide member. This packing actuator engages the lower end of a packing sleeve I2 surrounding the body, whose upper end is engageable with. the lower end of an expander I3, on which is threaded a packing retainer or abut-. ment I4 having an inturned flange I5 spaced from the end of the expander to form a groove in which is received an outwardly directed flange I6 extending from the upper end of the packing sleeve I2.

Whenever the packing is to be engaged with the wall of the casing A, the expander member I3 is held stationary by any suitable means, such as casing engaging slips (not shown) specifically described in the application referred to, and an upward strain taken on the tubular body III to move its actuator II longitudinally toward the expander I3, and thus shorten the packing sleeve l2, so as to expand it radially outwardly against the wall of the confining casing and effect an annular seal between it and the packer body.

It is to be noticed that the expanded packing material bridges the comparatively large annular space I I between the depending retainer I4 or the possibility that substantially all of the packing material would be dissipated and non-available for effecting its sealing function between the packer body and casing wall. Such possible dissipation is prevented by employing a segmental ring I8 adjacent the retainer I 4 capable of bridging the annular space I! upon expansion of the packing, so as to act as a barrier to the cold flowing of packing material therethrough. This ring I8 has a retracted diameter substantially equal to that of the packing sleeve I2, and is positioned in a circumferential groove l9 formed by a circumferential recess in the packing and the bottom surface 20 of the retainer.

The flow preventer is composed of adjacent upper segments 2| and adjacent lower segments 22 encircling and embracing the packing to form the composite ring I8. The lower segments 22 are staggered with respect to the upper segments 2| so as to lap over from one upper segment to the other upper segment and extend across their adjacent en'ds. For the purpose of maintaining this staggered or lapped arrangement, each of the upper and lower segments are secured to one another, as by a pin or rivet 23, in such manner as to have the unsecured or free end 22a of the lower segment extend under the next adjacent upper segment. In effect, the composite flow preventer ring I8 consists of a plurality-of'stepped segments having upper and lower portions overlapping one another to'eliminate longitudinal spaces between the segments extending completely therethrough.

One method of producing the packing structure disclosed in the drawings is to place the retainer I4 in a rubber mold and assemble the stepped segments 2|, 22 in overlapping relation therein in abutment with the lower end 20 of the retainer to form a substantially continuous rin of the proper retracted diameter. The proper amount of rubber or other packing material is then placed in the mold and vulcanized under heat and pressure to the desired initial. retracted shape (as disclosed in Figure 1). During the molding operation, the rubber packing material larged button 26 of rubber in the upper segments,

which prevents inadvertent disassembly of the segments from the rubber packing member. After the molding operation, the packing assembly, consisting of the packing sleeve I2, segments 2|, 22, and retainer I4 can he slipped over the body I0 and threaded on the expander I3.

The ends of the adjacent upper segments 2| and adjacent lower segments 22 practically contact one another when in retracted position. At the most, only an extremely small circumferential space '21 (exaggerated in Figures 1 and 3) remains between the adjacent segments in each row, and this, if present, is filled with rubber or other packing material during the molding operation. Upon distorting the rubber packing sleeve I2 into engagement with the casing by pressure, such as is created by pulling up on the body ID to move the actuator II toward the expander I3, the expansion of the packing material itself forces the segments 2|, 22 of the flow preventer ring I8 radially outward into engagement with the wall of the casing, to bridge the annular space I! between the retainer and casing. In moving to this latter position of greater diameter, the stepped segments 2|, 22 necessarily separate from one another to create a slight circumferential space 21a between the ends of the lower segments and the ends of the upper segments (exaggerated in Figures 2 and 4). This space 2111 is of too small an extent to permit passage of the packing material, but even should this tendency occur, the rubber material can do no more than fill the space so created, as is apparent from the fact that the spaces between the lower segments 22 are bridged by the upper segments 2 I, and the spaces between the upper segments are bridged by the lower segments. In other words, a continuous path does not exist through which the packing material can flow longitudinally from one end of the flow preventer ring I8 to its other end. As a result, the packing material remains at the desired sealing point in the casing, regardless of the well temperatures or pressures to which it is subjected.

Upon relieving of the pressure on the packing sleeve, as by lowering the body I0 and packing actuator I I, the inherent contractability of the packing sleeve I2 moves it inwardly to its initial retracted position, and because of its coupling to the segments by the buttons 26. the segments are also moved inwardly along the bottom end 20 of the retainer to retracted position, in which material clearance prevails with respect to the wall of the casing, allowing movement of the packer through the casing without restraint and without damage. especially to its packing parts.

For the purpose of assisting radial outward exbansion and inward radial contraction of the flow preventer segments 2|, 22, the bottom end 20 of the retainer is bevelled in an upward and outward direction. and the upper sides 28 of the flow preventer se ments are correspondingly bevelled. This inclined or bevelled engagement between the upper segments and retainer causes an upward pressure or strain on the packing material to produce lon itudinal movement of the segments 2 I, 22 upwardly along the retainer bevel 20 and outwardly into engagement with the wall of the casing. Correspondingly, retraction of the packing sleeve 12 toward its initial position causes return longitudinal movement of the segments and their radial inward movement to initial position. This retraction of the segments is made positive by the interlocking of the packing sleeve to. the segments through the agency of the buttons 26.

It is thus apparent that eifective means have been provided for preventing plastic flow of the packing material from the desired sealing region without impairing the retrievability or removability of'the well device. The packing I2 can be set and released repeatedly withthe small segments 2|, 22 moving into and out or engagement with the casing wall from and to their initially retracted position I claim: 5

1. A packing structure, including a normally retracted non-metallic packing adapted for outward expansion into engagement with the wall of a confining enclosure, abutment mean at one end of said packing to prevent substantial longitudinal movement of said packing end with respect to said abutment means, and a segmental ring encircling and embracing the end of said packing adjacent said abutment means while said packing is in retracted position as well as expanded position, said segments overlapping one another so as to extend across the ends of adjacent segments.

2. A packing structure, including a normally retracted non-metallic packing adapted for lateral expansion, abutment mean at one end of said packing to prevent substantial longitudinal movement of said packing end with respect to said abutment means, and a ring composed of a plurality of small stepped segments encircling and embracing theend of said packing adjacent said abutment means while said packing is in retracted and expanded positions, each of said segments comprising upper and lower steps overlapping lower and upper steps, respectively, of

adjacent segments.

3. A packing structure, including a non-metallic packing adapted to engage the wall of a well casing, abutment means at one end of saidpacking to prevent substantial longitudinal movement of said packing end with respect to said abutment means, said packing being provided with a circumferential recess adjacent said abutment means to form a circumferential groove therewith, and a ring in said groove composed of a plurality of small overlapping segment encircling and embracing said packing to prevent its longitudinal passage through said ring.

4. A packing structure, including a normally retracted non-metallic packing adapted for lateral expansion, abutment means secured to one end of said packing, and a ring circumscribing said packing adjacent said abutment means both while said packing is in retracted and expanded positions, said ring comprising upper andlower abutting segments arranged in overlapping relation so that the lower segments extend across the ends of adjacent upper segments.

5. A packing structure, including a non-metallic packing, abutment means secured to one end of said packing, said packing being provided with a circumferential recess adjacent said abutment means to form a circumferential groove therewith, and a ring in said groove encircling and embracing said packing, said ring comprising upper and lower small abutting segments arranged in overlapping relation so that the lower segments extend across the ends of adjacent upper segments.

6. A packing structure, including a non-metallic packing, abutment means at one end of said packing to prevent substantial longitudinal movement of said packing end with respect to said abutment means, and a ring encircling and embracing said packing adjacent said abutment means, said ring comprising upper and lower segments molded to said packing and arranged in overlapping relation so as to extend across the ends of adjacent segments.

7. A packing structure, including a non-metallic packing adapted to engage the wall of a well casing, mean secured to one end of said packing to retain the same, said packing being pro vided with a circumferential recess adjacent said retaining means to form a circumferential groove therewith, and a ring in said groove encircling and embracing said packing, said ring comprising upper and lower small segment molded to said packing and arranged in overlapping relation so that the lower segments extend across the ends of adjacent upper segments.

8. A well packer, including a non-metallic packing adapted to engage the wall of a well casing, means secured to one end of said packing to retain the same, said packing being provided with a circumferential recess adjacent said retaining means to form a circumferential groove therewith, and a ring in said groove encircling and embracing said packing, said ring comprising upper and lower small segments molded to said packing and arranged in overlapping relation so that the lower segments extend across the ends of adjacent upper segments, the end of said retaining means forming said groove having a bevelled surface inclined in an outward and upward direction and said upper segments having a corresponding bevel abutting therewith,

9. A packing structure, including a non-metallic packing, abutment means at one end of said packing to prevent substantial longitudinal movement of said packing end with respect to said abutment means, said abutment means having a bevel surface, said packing having a circumferential recess adjacent said abutment means to form a circumferential groove with said bevel surface, and a ring in said groove composed of a plurality of segments encircling and embracing said packing, the segments of said ring 'having bevel surfaces engaging the bevel surface of said abutment means.

CHARLES M. ENG.