US2921633A - Packing flow preventing device - Google Patents

Description

Jan. 19, 1960 R. c. BAKER 2,921,633

PACKING FLOW PREVENTING DEVICE Filed March 5, 1956 J7 ,3 J9 g 26 d %20a 4 4 .294 36 -540 E6, 3. 2-

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- failure of the packing member. well packer is of the retrievable type, embodying an United States Patent PACKING FLOW PREVENTING DEVICE Reuben C. Baker, Coalinga, Califi, assignor to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Application March 5, 1956, Serial No. 569,618

7 Claims. (Cl. 166-204) The present invention relates to packing devices for forming a seal against a companion wall, and more particularly to well packers embodying packing structures for effecting seals against the walls of well casings, or similar conduits, disposed in well bores.

Well packers are run in a well bore to a desired location therewithin, at which the packer is to be sealed 011 against the well casing, or similar conduit, disposed in the well bore. The packer ordinarily includes a nonmetallic packing member made of rubber or rubber-like material which packs off against the well casing. The

packing member is prevented from moving longitudinally along the remaining parts of the well packer by an abutment portion of the latter, which has substantial clearance with the wall of the well casing, to permit the well packer to be lowered and elevated within the well casing, free from interference by the abutment portion. In view of the provision of the substantial clearance around the abutment portion, a relatively wide annular space exists between it and the wall of the well casing into which the non-metallic packing member attempts to cold flow when subjected to high pressures or high temperature conditions, or a combination of the two. Under some situations, a substantial portion of the packing material may be dissipated through the clearance space, resulting in In the event that the expansible and retractable non-metallic packing, the forceing of substantial packing material into the clearance space referred to above, when the packing member is in its expanded condition, results in the inability to. subsequently retract the packing member.

Accordingly, it is an object of the present invention to prevent the cold flowing or dissipation of packing material into the clearance spaces around a well packer, insuring the continued presence of the packing material to perform its required purposes of effecting a leak-proof seal against an adjacent member, such as the wall of a well casing, despite the existence of high temperature or high pressure conditions, or both.

Another object of the invention is to provide a well packer, which includes an expansible and contractible device for preventing the cold flow of packing materials through the clearance space around the well packer, the device being normally in retracted position, and being adapted to bridge the clearance space only when the packing material is subjected to relatively high pressures or temperatures. When the high pressure or temperature condition is relieved, the device returns to its normal, retracted position, to avoid any drag on the wall of the well casing.

A further object of the invention is to provide a wellpacker embodying a device for preventing cold flow of packing material through the clearance space around the well packer, in which the device is capable of returning automatically from its expanded to its retracted posi- 23,921,533 Patented Jan. 19, 1960 ice tion, the device also being of very high strength and being parent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustratingthe general principles of the invention; but it 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 combined side elevational and longitudinal sectional view through a portion of a well packer embodying the invention, with the parts disclosed in retracted position;

Fig. 2 is a view similar to Fig. 1, with the parts in their expanded position;

Fig. 3 is an enlarged fragmentary longitudinal section of a portion of the apparatus, taken along the line 3---3 in Fig. 2.

.surface Well Too generally for preventing the cold flow of rubber, or

similar non-metallic, packing members through the clearance space around the well apparatus and adjacent the packing apparatus.

As shown in the drawings, a well packer A is provided having a tubular body 10 suitably connectible toya tubular string (not shown), such as tubing or drill pipe, extending to the top of the well casing B, in which the apparatus is used. The tubular body, can be anchored to the well casing against upward movement by a plurality of circumferentially spaced slips 11, which are normally in a retracted position, and which may be expanded outwardly into anchoring engagement with the wall of the well casing by an expander 12 therebelow slidably mounted on the body 10 of the tool and having an external tapered or frusto-conical expander surface 13 adapted to coact with companion internal surfaces 14 in the slips. When the expander 12 moves upwardly within the slips 11, it will shift the latter outwardly until the slip wickers 15 are embedded in the casing, the expander'being wedged firmly behind the slips.

The well packer A also includes a packing structure 16 below the expander 12, consisting of a compression or booster sleeve 17 slidably mounted on the body 10 and threadedly secured to the expander 12. Encompassing the booster sleeve is an inherently contractible packing sleeve 18, made of rubber or rubberlike material, the upper end 19 of which is received within an upper expander member 20 slidably mounted on the compression sleeve 17, and which may be initially spaced by a relatively small amount from the lower end 21 of the expander 12, which functions as an abutment member in securing the outward expansion of the packing sleeve, in the manner described hereinbelow. The abutment member 21 may also be constituted by a fixed gage ring 22 threadedly secured on the lower portion of the expander and having an external diameter substantially less than the internal diameter of the well casing B, providing a substantial clearance space 23 therebetween. The expander member 20 has upwardly extending stop lugs 24 adapted to engage the expander or abutment 21, in order to limit the extent of upward movement of the expander member along the compression sleeve 17.

The expander member 20 has a cylindrical portion 25 which merges into a downwardly diverging or frustoconical portion 26 spaced from the compression sleeve 17 to form an annular pocket therebetween receiving the upper end 19 of the packing sleeve. The downwardly diverging portion 26 has an externally tapered surface 27, which is inclined in a downward and outward direction, engaging a companion tapered surface 28 on the lower portion of an upper expandible gage ring 29, which is inherently contractible, and which normally occupies an inward position with its inner surface 30 in contact with the cylindrical periphery of the expander member 20. The expandible gage ring 29 is a onepiece, split member and when in contracted condition has an external diameter which is preferably no greater than the external diameter of the fixed gage ring 22.

The expandible gage ring 29 has a lap joint at its split, the lap joint being provided by a step 31 at one end of the ring overlapping a companion step 32 extending from the other end of the ring, one step extending within a recess 33 formed in the opposite end portion of the ring. The steps abut and are slidable upon one another, in order that the expandible gage ring be circumferentially continuousmore than 360 degrees in extent and providing no longitudinal gaps therethrough, both when the expandible gage ring 29 is in retracted position, as well as when it is in its expanded position. The expandible gage ring 29 is of sufficient thickness to have its upper end 34 shoulder substantially against the lower surface of the fixed gage ring or abutment 22 when the periphery of the expandible gage ring engages the wall of the well casing B.

The lower portion 19:: of the packing sleeve is received within a lower expander member 20a slidably mounted on the compression sleeve 17, this lower expander member being identical to the upper expander member 20, but oppositely arranged on the compression sleeve. The lower end 19a of the packing sleeve is received within a pocket formed between the upwardly diverging portion 26a of the lower expander member 20 and the compression sleeve 17, this diverging portion providing an external upwardly diverging tapered surface 27a engaging a companion tapered surface 28a on a lower expandible gage ring 29a, which may also be identical with the upper expandible gage ring 29, although reversely arranged. As a matter of fact the lower expandible gage ring 29a and lower expander member 200 cooperate with each other in the same manner as the upper expandible gage ring 29 and the upper expander member 20, the lower set merely being oppositely arranged to the upper set. The lower expander member 20a is also spaced initially by a slight distance above a lower abutment member 35, provided by a lower fixed gage ring contacted by the lower end 34a of the lower expandible ring 29a. This fixed gage ring 35 has an inwardly directed flange 35 extending to the periphery of the compression sleeve 17, being disposed above an outwardly directed shoulder 37 formed on the latter. The lower fixed gage ring 35 is threadedly secured to a tubular thrust sleeve 38, the lower end of which is threadedly attached to a guide member 39 threaded or otherwise attached to the tubular main body of the tool.

The upper and lower expandible gage rings 29, 29a require a substantial expansible force before they will be shifted outwardly into engagement with the wall of the well casing. As an example, a longitudinal force may be required on each expander member of the order of about 10,000 to 25,000 pounds, before an expander member 20 or 20a can fully shift an expandible gage ring 29 or 29:: against the wall of the well casing. Before such relatively high forces are imposed on the particular expander member and companion expandible gage ring,

4 the latter will remain in its fully or at least partially retracted position.

In the use of the apparatus A disclosed, it is run in the well casing B with the parts in the retracted positions shown in Fig. 1, until the location is reached at which the well packer is to be anchored in packed-01f condition against the casing. As disclosed in the aboveidentified patent application, upward movement of the initially retracted slips 11 within the well casing is resisted, so that upward movement of the tubular string (not shown) and the body 10 attached thereto will shift the guide member 39 and thrust tube 38 upwardly, this upward motion being transmitted to the lower gage ring 35, lower expandible gage ring 29a, lower expander member 20:: and packing sleeve 18, then to the upper expander member 20, upper expandible gage ring 29 and the upper slip expander 12. The upper slip expander 12 is movedupwardly relative to the slips 11, its expander surface 13 engaging the inner surfaces 14 of the slips, to shift the latter outwardly into engagement with the well casing B. When the expander has been firmly wedged behind the slips, to embed their wickers 15 into the wall of the well casing, further upward movement of the expander 12 cannot occur. As a result, the expander functions as a fixed upper abutment, preventing further upward movement of the upper expandible gage ring 29 and resisting upward movement of the upper expander member 20 and the rubber or rubber-like packing sleeve 18. Accordingly, a continuation of the upward movement of the body 10 will cause the guide member 39, thrust tube 38, lower gage ring 35, low expandible gage ring 29:: and lower expander member 20a to move upwardly toward the upper expander member 20 and upper gage ring 29, the expandible gage rings 29, 29a, as stated above, remaining in their retracted position until substantial longitudinal force is imposed thereon. Accordingly,

' the packing sleeve 18 is foreshortened and compressed between the upper and lower expander members 20, 20a, shifting outwardly until it comes into substantially full sealing engagement with the wall of the well casing B.

Following outward expansion of the packing sleeve 18 against the wall of the well casing, if the upward force imposed on the body 10, guide member 39, and thrust tube 38 becomes substantial, such force will be exerted through the packing sleeve 18 upon the upper expander member 20, shifting the latter upwardly along the compression sleeve 17 and the expandible gage ring 29, expanding the latter outwardly until its periphery engages the wall of the well casing. Expansion of the upper gage ring 29 can occur in view of the fact that it is split at one side. When engaged with the wall of the well casing, the upper expandible gage ring 29 will still be in contact with the fixed gage ring 22 of the upper abutment member (Fig. 2).

In a similar fashion, the longitudinal force exerted on the packing structure 16 may move the lower expandible gage ring 29a upwardly along the lower expander member 200, the companion tapered surfaces 28a, 27a on the two parts causing the lower expandible gage ring 29:: to be shifted laterally until it engages the wall of the well casing. When so engaged, the lower expandible gage ring 29a still contacts the lower fixed gage ring or abutment member 35.

When expanded outwardly, it is to be noted that both expandible gage rings 29, 29a bridge the annular clearance space 23 between the fixed gage ring 22 or 35 and the wall of the well casing. In view of the step, lap joint 31, 32 at the split portion of each ring, there are no longitudinal gaps through either of the expandible gage rings when they are fully expanded against the wall of the well casing. A circumferentially continuous ring is effectively provided, which fully bridges the annular clearance spaces 23 around the abutment members 22, 35, and also the clearance spaces 23a between the expander members 20, 20a themselves and the wall of the well casing. Accordingly, if there is any tendency for the rubber'or rubber-like packing material to be. shifted from its sealing region, the expandible gage rings 29, 29a function as bridges that close such clearance spaces, and prevent the packing material from flowing thereinto and therethrough. The packing material can only shift around an expander member 20 or 20a until it engages the expandible gage ring 29 or 29a.

It may be unnecessary to exert an upward force on the body to expand both the packing sleeve 18 and an expandible gage ring 29 or 29a outwardly into sealing engagement with the wall of the Well casing, it being suflicient for the upward pull on the body 10 to fully expand the packing sleeve only into sealing engagement with the wall of the Well casing. The expandible gage rings 29, 29a may remain in their retracted position, or may be only partially expanded. However, should there be a high pressure condition existing in the well casing below the well packer, such pressure will be exerted in an upward direction over the expanded packing sleeve 18, and if it becomes very high it will effect a shifting of the upper expander member 20 in an upward direction relative to the upper expandible gage ring 29, shifting the latter outwardly against the wall of the well casing.

Such engagement of the expandible gage ring 29 with the casing wall occurs before any substantial extruding or forcing of the packing material can occur arround the upper expander member 20. Upon relieving of the pressure, the upper expandible gage ring 29 retracts inherently to its initial position, or at least partially to such position in the event the high pressure were only partly relieved.

If, on the other hand, a high pressure condition is present in the annulus between the body 10 of the tool and the well casing above the packing structure 16, such pressure will act in a downward direction on the packing sleeve 18, the upper expandible gage ring 29 partially or completely retracting, and the high pressure acting in a downward direction on the packing sleeve 18 to force the lower expander member 20a downwardly within the lower expandible gage ring 29a, shifting the latter outwardly into contact with the wall of the well casing. The packing sleeve 18 slides downwardly along the wall of the well casing while remaining in sealed off condition therewithin, as pointed out in the patent to M. B. Conrad et al., Patent No. 2,675,876, which discloses a packing structure generally similar to the packing structure disclosed in the present application, with the exception of the feature of preventing the cold flowing of packing material through the clearance spaces.

It is evident that the lower expandible gage ring 29a will bridge the annular clearance space 23a between the lower expander member 20a and the Wall of the well casing, serving as a bridging device to prevent the packing material from flowing beyond such clearance space and into the clearance space 23 around the lower abutment member 35. Here again, although a substantial force is preferably required before the lower expandible gage ring 29a is shifted out against the well casing, yet the force required is less than the force that must be imposed on the packing sleeve 18 before it will begin to extrude into the clearance space 23a around the lower expander member.

If the tool is to be released from the well casing, the pressure is relieved and the tubular string (not shown) and thebody 10 of the tool lowered, which will shift the thrust tube 38 and lower gage. ring 35 downwardly relative to the compression sleeve 17,. thereby removing the longitudinal force on the packing sleevelS and the gage rings 29, 29a, which will inherently retract to their initial positions disclosed in Fig. 1. The continuation of the downward movement of the body 10 will then cause the lower fixed gage ring flange 36. to engage the compression sleeve shoulder 37, pulling the expander 12 downwardly with respect to the slips 11,- the latter then moving to their retracted positions, as described in the above-identified patent application. The well apparatus A can now be shifted longitudinally! in the well casing to a new setting location, either above or below the previous setting point, or may be elevated in the well casing and removed completely therefrom at the top of the hole.

In order to prevent the. expansion of the expandible gage rings 29, 29a to the extent at which they may ride off the adjacent fixed abutment members 22, 35, or the expander members 20, 20a, the initial space 40 between the end of each expander member and the adjacent abutment member 21 or 35 is limited, so that each expander member 20 or 20a will engage its adjacent abutment member and thereby place a definite limit upon the extent of lateral expansion of the associated expandible gage ring 29 or 29a. An expander member 20 or 20a will ordinarily not engage anabutment member 22 or 35, as disclosed in Fig. 2, but will still be spaced a slight distance therefrom. However, if the apparatus happens to be run in an oversize casing, then the expander members 20, 20a will engage their associated abutment members, the expandible gage ring only being shifted outwardly to a predetermined maximum extent, which will still substantially bridge the clearance space around the abutment members 22, 35 and reduce'considerably such space. To that extent they will minimize extrusion of the rubber or rubber-like packing material into the clearance space 23.

It is, accordingly, apparent that a device has been provided which prevents cold flowing of the packing material from its intended sealing region, the device only becoming effective when it is required, and returning to its initial retracted position after its function is no longer necessary. Thus, the device lends itself for use in a retrievable well packer, or similar retrievable tool, to be used in a well bore, since its positive return to its retracted position will insure that it does not afford any resistance to longitudinal movement of the apparatus in the well casing.

The inventor claims:

1. In a packing structure: a pliant packing engageable with a surrounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member providing a clearance space with the companion member; a one-piece inherently contractible flexible ring engaging said abutment means and said expander member and expandible by said expander member laterally outward into engagement with the companion member upon movement of said expander member toward said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on said opposite sides of its split being stepped and overlapping and engaging each other when said ring is expanded against the companion member, whereby said split is closed to prevent passage of packing materialtherethrough. i

2. In a packing structure: a pliant packing engageable with a surrounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member having a tapered surface and providing a clearance space with the companion member; a one-piece inherently contractible split flexible ring engaging said abutment means and said tapered surface and expandible by said tapered surface laterally outward into engagement with the companion member upon movement of said expander member toward said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on opposite sides of its split being stepped and overlapping and engaging each other when said ring engages the companion member, whereby said split is closed to prevent passage of packing material therethrough.

3. In a packing structure: a pliant packing engageable with a surrounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member providing a clearance space with the companion member and having a tapered surface converging in a direction toward said abutment means; a one-piece inherently contractible split flexible ring engaging said abutment means and said tapered surface and expandible by said tapered surface laterally outward into engagement with the companion member upon movement of said expander member toward said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on opposite sides of its split being stepped and overlapping and engaging each other when said ring engages the companion member, whereby said split is closed to prevent passage of packing material therethrough.

4. In a packing structure: a pliant packing engageable with a surounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member providing a clearance space with the companion member and having a tapered surface converging in a direction toward said abutment means; a one-piece inherently contractible split flexible ring engaging said abutment means and said tapered surface and expandible by said tapered surface laterally outward into engagement with the companion member upon movement of said expander member toward said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; said ring having a stepped portion on each side of its split disposed within a recess on the other side of the ring split and engaging the opposite stepped portion when said ring engages the companion member to provide a ring having an arcuate extent of more than 360 when said ring engages the companion member.

5. In a packing structure: a pliant packing engageable with a surrounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member having a tapered surface and an external cylindrical surface, said expander member providing a clearance space with the companion member; a one-piece inherently contractible split flexible ring surrounding and engaging said cylindrical surface when in contracted position, said ring engaging said abutment means and said tapered surface and expandible by said tapered surface laterally outward into engagement with the companion member upon movement of said expander member to ward said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on opposite sides of its split being stepped and overlapping and engaging each other when said ring engages the companion member, whereby said split is closed to prevent passage of packing material therethrough.

6. In a packing structure: a pliant packing engageable with a surrounding companion member; ab ltment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and initially spaced from said abutment means, said expander member having a tapered surface and an external cylindrical surface, said expander member providing a clearance space with the companion member; a one-piece inherently contractible split flexible ring surrounding and engaging said cylindrical surface when in contracted posi tion, said ring engaging said abutment means and said tapered surface and expandible by said tapered surface lateral-1y outward into engagement with the companion member upon movement of said expander member to wards said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on opposite sides of its split being stepped and overlapping and engaging each other when said ring engages the companion member, whereby said split is closed to prevent passage of packing material therethrough; said expander member being engageable with said abutment means to limit the extent of lateral shifting of said ring by said expander member.

7. In a packing structure: a pliant packing engage-' able with a surrounding companion member; abutment means adjacent said packing and providing a clearance space with the companion member; a rigid, non-deformable expander member engaging said packing and in which said packing is nested and initially spaced from said abutment means, said expanded member having a tapered surface and an external cylindrical surface, said expander member providing a clearance space with the companion member; a one-piece inherently contractible split flexible ring surrounding and engaging said cylindrical surface when in contracted position, said ring engaging said abutment means and said tapered surface and expandible by said tapered surface laterally outward into engagement with the companion member upon movement of said expander member towards said abutment means to bridge said clearance spaces while maintaining said ring in engagement with said expander member and abutment means; portions of said ring on opposite sides of its split being stepped and overlapping and engaging each other when said ring engages the companion member, whereby said split is closed to prevent passage of packing material therethrough; said expander member being engageable with said abutment means to limit the extent of lateral expansion of said ring by said expander member.

References Cited in the file of this patent UNITED STATES PATENTS 1 McBride Mar. 28, 1905

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