High Temperature Well Packer

The present invention relates to improvements in well bore packers adapted to be set in a well casing in response to a tension or upstrain applied to a running pipe or tubing and adapted to be retrieved by pullng on the running pipe string, the packer assembly being particularly well suited for use in a high temperature well where it is subjected to temperature variations as well as high temperature.

More particularly, the invention combines features of the aforesaid patent with other structural characteristics to provide an improved high temperature packer which is set in the well casing and retrieved therefrom by taking a pull on the tubing string, but without requiring rotation of the tubing string except to release a control device when the packer is initially set in the well bore and to release a connection between the packer body and the tubing to allow the tubing to be spaced out.

Once set, the packer has a body locking structure which obviates the necessity of subsequent tightening of the packing element to prevent leakage. This is accomplished by locking the packer body and the anchor slip expander cone against movement of the cone from beneath the anchor slips, notwithstanding expansion and contraction due to heat variations. However, the body can be pulled upwardly relative to the cone through the lock upon the shearing of a shearable member which maintains the compressive load on the resilient packing element.

Furthermore, in the event that even after applying a pull to the tubing string, the packing structure does not release, the tubing string can be released from the packing structure and retrieved from the well. This is accomplished by providing a guide on the lower end of the slick joint which can be engaged with the packer body and removed from the slick joint by rotation of the tubing string, thus enabling the slick joint to be pulled upwardly from the packer body.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent 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 illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIGS. 1a and 1b, together, constitute a view in elevation with a fragmentary longitudinal section, illustrating a packer assembly made in accordance with the invention and set in a well bore casing with the tubing spaced out, FIG. 1b being a downward continuation of FIG. 1a;

FIGS. 2a, 2b, and 2c, together, constitute a longitudinal quarter section illustrating the packer assembly of FIGS. 1a and 1b in condition for running into the well casing, FIGS. 2b and 2c being successive downward continuations of FIG. 2a;

FIGS. 3a and 3b, together, constitue a view partly in longitudinal section and partly in elevation, showing the packer assembly in anchored and set condition in the well casing, FIG. 3b being a downward continuation of FIG. 3a;

FIGS. 4a, 4b, and 4c, together, constitute a longitudinal quarter sections illustrating the packer assembly released for retrieval from the well casing, FIGS. 4b and 4c being successive downward continuation of FIG. 4a;

FIG. 5 is a fragmentary view as taken on the line 5--5 of FIG. 4b, illustrating the control slot for the packer.

As seen in the drawings, referring first to FIGS. 1a and 1b, the invention provides a packer assembly P adapted to be connected to a length of running pipe or tubing T to be run into a well bore casing C set in a well, such as a fluid injection or production well, drilled into the earth. The packer assembly includes an elongated inner body 10 having thereon casing engaging normally retracted, but laterally expansible anchor means 11 and a resiliently deformable packing element 12 adapted to be set in sealing engagement within the casing C. When the packing assembly is set in the casing, an internal, elongated tubular member or slick joint 13 extends reciprocably through the packer assembly, being initially releasably connected to the packer body by means of a left-hand thread 14 on the slick joint and an internal companion thread 15 within the upper end of a tubular body member 16. When the slick joint is released from the packer body, the tubing is free for expansion and contraction caused by temperature changes within the well, without applying load to the packer assembly. At the lower end of the slick joint 13 is a guide nose 17 which, in some installations, may have a downwardly extended length of tubing (not shown) connected thereto for extending further downwardly in the well bore.

The packer assembly is adapted to be run into the well bore with the anchor means 11 retracted and with the packing element 12 released for freedom of movement of the assembly downwardly through the well casing. When the packer assembly is disposed at a predetermined location in the well casing, it is adapted to be anchored and set upon release of the body control means to be hereinafter described, by simply taking tension upon the running in pipe or tubing T, thereby causing the anchor means 11 to be expanded into anchoring engagement with the casing and then causing deformation and expansion of the packing element 12 into sealing engagement with the casing. Release of the packer assembly for retrieval from the well is also accomplished by simply taking further tension on the running pipe string T to release the packing element 12 from sealing engagement with the casing and then causing release of the anchor means 11. In the event that the packing assembly cannot be readily released from anchoring engagement with the well casing, the guide nose 17, as will be later described, can be released from the lower end of the slick joint, allowing the slick joint and tubing to be pulled from the well.

Referring to FIGS. 2a through 2c, the packer structure is shown in condition to be run into the well casing C on the tubing string T. The body structure 16 includes an elongated tubular body member 20 having at its upper end a threaded connection 21 with a further upwardly extended sealing nipple 22 having the internal left-hand thread 15 referred to above, adjacent its upper end. The slick joint structure 13 includes an elongated tubular sealing body 23 extending longitudinally within the sealing nipple 22 and sealingly engaged within an internal packing 24 carried within the sealing nipple 22 between a downwardly facing shoulder 25 and a lower retainer ring 26 carried within the sealing nipple. At its upper end, the tubular slick joint member 23 has a connector sleeve 27 threadedly connected at its upper end, at 28, to the running or tubing string T and at its lower end threadedly connected at 29 to the downwardly extended slick joint member 23, which extends from the lower end of the tubular packer body 20, as seen in FIG. 2c. The left-hand threaded connection 14, 15, between the sealing nipple 22 and the slick joint connector 27 is initially locked against release by suitable means such as a shear screw or pin 30. At its lower end, the tubular slick joint member 23 has the guide nose 17 threadedly connected thereto at 31, the threaded connection being initially locked by a suitable, shearable member or screw 32 threadedly carried by the guide 17 and extending into a recess 33 in the outer periphery of the slick joint member 23.

The anchor means 11 comprises a rocking slip and drag block assembly 34 and a cone or expander member 35 carried by the body 20. The rocking slip and drag block assembly includes a stop ring 36 disposed about the body and having a radially inwardly projecting control pin or screw 37 extending into an inverted J-slot 38 formed within the body 20 (see FIG. 5). Extending downwardly from the stop ring 36 is a slip carrier ring or sleeve 39 having a number of circumferentially spaced radially opening slots 40 in which are rockably disposed slip and drag block members 41 having drag portions 42 normally forced outwardly by a coiled spring 43 disposed between the drag portion 42 and the carrier ring 39 at the bottom of the slot 40, the drag member 42 being retained in the slot by a retainer ring 44 extended about the rocking slip and drag members and received within an outwardly opening slot 45 in the latter. Extending downwardly from the drag portion 42 of each rocking slip and drag member is a slip section 46 having an inner, downwardly, and outwardly inclined wedge surface 47 and having outer, upwardly facing wickers or anchor teeth 48, which are adapted to be expanded into biting or anchoring engagement within the casing C by a downwardly and outwardly inclined upper end surface 49 provided on the expander cone member 35. This expander member 35 is disposed about the packer body 20 and has one or more shear pins or screws 50 carried thereby and projecting inwardly towards the body above a slip pickup ring 51 which extends circumferentially of the body and is disposed in an annular groove 52 therein.

The expander cone member 35 is a tubular member having therein body locking means generally indicated at 53, whereby during setting of the packer assembly in the well casing, as will be later described, the body 20 can be moved upwardly with respect to the expander cone 35 and will be locked in the upwardly shifted position after the anchor slips have been set and the packing element 12 has been deformed into sealing engagement with the casing. Such a body locking means is more particularly the subject of the prior United States patent granted to J. R. Baker et al., on Aug. 4, 1953, U.S. Pat. No. 2,647,584. This body locking means comprises a longitudinally split, resilient lock ring or sleeve 54 carried by the cone member 35 and having internal ratchet teeth 55 engageable with external ratchet teeth 56 on the packer body 20, when, as will be later described, the body is moved upwardly through the lock ring 54, during setting of the packer. As indicated above, the packer is set by upward movement of the body 20. Such relative movement can occur without interference since the internal ratchet teeth 55 on the lock sleeve merely ratchet over the corresponding ratchet teeth or roughened surface 56 of the body, without substantial resistance to its movement. However, any tendency of the body to move downwardly with respect to the cone is prevented by the locking engagement of the internal teeth of the lock sleeve with the roughened surface or teeth of the body. In effect, the ring or sleeve 54 operates as a one-way coupling or clutch element permitting relative movement of the body upwardly, but precluding downward movement. Any tendency of the ring 54 to move downwardly within the cone is resisted by wedging of the tapered cam surfaces of its outer teeth 57 with the companion cam surfaces or teeth 58 within the expander member 35. These opposing teeth 57 and 58 form inclined surfaces of the buttress type threads on the lock ring and in the expander member, and the wedging action of these surfaces urges the lock ring 54 inwardly into the body 20 with greater force when the body tends to move downwardly.

The packing element 12 is disposed about the body 20 below the expander cone member 35, between an upper spacer ring 59 and a lower guide assembly 60. The guide assembly 60 includes a lower member or sleeve 61 and an upper member 62 threadedly interconnected by suitable screws 63 to define an internal annular groove 64 which receives a shear ring or shear ring segments 65 having an internal projection 66 extending into an annular groove 67 in the outer periphery of the body. The packing element 12 is adapted to be set in sealing engagement with the well casing, when, in response to upward movement of the body 20, the guide 60 is moved upwardly toward the spacer ring 59. The packing element 12 includes a central annular body section 68 composed of elastomeric or resiliently deformable material having upper and lower plastic or "TEFLON" backup rings 69 and metallic backup or anti-extrusion rings 70 all of which are deformed as the guide 60 moves upwardly towards the spacer ring 59 to axially deform and circumferentially outwardly expand the resilient packing element. The specific form of the packing element is not germane to the present invention, but the elastomeric element illustrated at 68 is one which has a suitable number of radial ports 71 formed therein, whereby fluid pressure from within the casing can find access to annular chambers 72 formed within the packing element, such pressure acting on the element to effect a tighter seal within the casing, when the packing is set, as will be later described.

Referring to FIGS. 3a and 3b, the packer assembly is shown as having been anchored and set within the well bore. When the packer assembly is lowered within the casing on the tubing T to the location at which the packer is to be set, the tubing string is rotated to the left to release the control mechanism or J-lock 37, 38, to enable continued upward movement of the body 20 with respect to the slip mechanism. The slip mechanism remains stationary within the casing C by virtue of the frictional engagement of the drag sections 42 of the rocking slip structures, while the expander cone 35 is moved upwardly by the thrust imparted thereto from the guide structure 60, through the retracted packing element 12. As the expander surface 49 of the upper end of the cone engages with the inclined surfaces 47 of the slip elements 46, the slips are rocked outwardly into engagement with the casing C, to resist upward movement of the cone 35 and the packing element 12. Continued upward movement of the body 20, then more tightly anchors the slips in engagement with the casing, as the body ratchets upwardly through the lock ring 54 and the packing element 12 is progressively deformed to the condition shown in FIG. 3b at which the packing is fully deformed and the slips fully anchored. In order to assure that the slips are first anchored tightly in engagement with the casing, before deformation of the packing element 12, the cone 35 carries one or a plurality of the shearable members 50, referred to above, which after anchoring engagement of the slips with the casing are sheared to permit the packing element 12 to then be deformed.

At this time, the left-handed threaded connection 14, 15, between the slip joint connector member 27 and the sealing nipple 22, can be released by rotation of the tubing T, causing the initial locking screws 30 to be sheared and enabling the release of the threaded connection. The tubing T can then be elevated to the position shown in FIGS. 1a and 1b so that the slick joint tube 23 is more or less shiftably disposed within the set packer structure with the packing means 24 forming a seal between the slick joint and the interior of the packer body, to prevent the flow of fluid therebetween, with the deformed packing element 12 sealingly engaged with the casing C to prevent the passage of fluid along the outside of the body. Changes in temperature in the well, which can cause expansion and contraction of the tubing string T, under the circumstances just described, have no effect on the holding and sealing effect of the packer structure.

Referring to FIG. 3b, it will be noted that when the packer assembly is set and anchored in the well bore, the body lock means 53 releasably holds the slip elements expanded by the expander cone and the packing element deformed between the axially spaced and fixed stops provided by the slips, at the upper end, anchoring against the casing, and by the shearable or frangible end sections 66 of the shear ring or segments 65, engaging with the body at the lower end. Accordingly, when it is desired that the packing assembly be released for retrieval from the well casing, as seen in FIGS. 4a through 4c, it is only necessary to take a further upstrain or tension on the tubing string T sufficient to cause the shearing of the projections 66 from the shear ring or segments 65, as seen in FIG. 4c. When this is done, the holding force is relieved from the resilient packing element, as the guide member 60 is allowed to move downwardly along the body, such downward movement being arrested by a pickup ring 60a provided in the outer periphery of the packer body adjacent its lower end. In addition, as seen in FIG. 4b, the pickup ring 51 carried by the packer body above the body lock means 53, shoulders at 51a with the lower, inner end of the slip support ring 39, so that the slips are pulled upwardly with respect to the cone 35, and the packer assembly can then be moved vertically from the well casing.

It may sometimes occur that the slip or anchoring structure is incapable of release due to accumulation of debris or sediment, or due to corrosion, and the like, in which case it is nevertheless desirable to be able to retrieve from the well bore the tubing string extended between the top of the well and the stuck packer.

Referring to FIGS. 2a and 4c, it will be seen that the lower guide 17, at the lower end of the slick joint 23 and the lower end of the packer body 20 have cooperative clutch means which enable the guide to be held against rotation while the tubing string T is rotated, so that the left-hand thread 31 can be disconnected between the guide 17 and the slick joint, following shearing of the screw 32. To accomplish this, it is simply necessary to elevate the tubing string to bring into opposing relation longitudinally extended opposed ends 17a on the guide 17 and 17b on the lower end of the body, followed by rotation of the tubing string to the right and the guide 17 will be progressively threaded downwardly from the lower end of the slick joint. The guide 17 will remain in the well together with any tailpipe which may be suspended therefrom, but the tubing string can then be retrieved from the well bore with the slick joint secured thereto.

From the foregoing, it will be apparent that the present invention provides a novel packer structure which is easy to operate, in that it can be set in response to simple longitudinal strain on a running string of pipe and then retrieved by the application of further longitudinal pull to the running string. The resilient body lock permits the necessary longitudinal motion to occur, as the packer is being set and released, and also provides means, in combination with the shearable elements 66 on the shear ring or segments 65, to retain the packer in effective packed off condition within the well casing.