Title:
APPARATUS FOR SETTING A LARGE BORE PACKER IN A WELL
United States Patent 3776307


Abstract:
Apparatus for setting a large bore packer in a well penetrating subterranean formations characterized by a packer assembly including an expansible liner that can be expanded into contact with the conduit, such as casing, of the well for tight sealing engagement without requiring setting anchors or the like; connector means that is connected with the liner at one end and connected with a seal sub at the other end, the seal sub having an unusually large bore for receiving a sealing relationship a large bore, or seal unit; and settable retainer, such as slips and cones, for effecting a supplementary retaining force in addition to that of the expanded liner for setting the large bore packer at a given depth and retaining it there against unusually large forces. Also disclosed is a combination of the apparatus with setting tool, swage, and retainer setting means, as well as specific preferred embodiments.



Inventors:
YOUNG J
Application Number:
05/283322
Publication Date:
12/04/1973
Filing Date:
08/24/1972
Assignee:
GEARHART OWEN IND INC,US
Primary Class:
Other Classes:
166/138, 166/207
International Classes:
E21B23/06; E21B33/12; E21B43/10; (IPC1-7): E21B23/04; E21B43/10
Field of Search:
166/206,207,123,125,138
View Patent Images:
US Patent References:
3722588SEAL ASSEMBLY1973-03-27Tamplen
3669190METHODS OF COMPLETING A WELL1972-06-13Sizer et al.
3667543RETRIEVABLE WELL PACKER1972-06-06Dean
3412565Method of strengthening foundation piling1968-11-26Lindsey et al.
3358760Method and apparatus for lining wells1967-12-19Blagg
3162245Apparatus for lining casing1964-12-22Howard et al.



Primary Examiner:
Brown, David H.
Claims:
What is claimed is

1. A combination of a packer assembly and apparatus for setting the packer assembly in conduit in a well penetrating subterranean formations comprising:

2. The combination of claim 1 wherein said swage means is disposed below said liner; said adapter rod means passes through said liner for pulling said swage means upwardly through and completely out of the top of said liner; said setting sleeve means is disposed above said liner with its lower end portion engaging the top of said liner and has means at its upper end portion for engagement with the force generating means and adapted for transmitting a downwardly acting said reaction force for opposing upward movement of said liner when said swage means is pulled upwardly therethrough; said setting sleeve means has means allowing movement of said swage means completely out of the top of said liner and within a portion of said setting sleeve means while said reaction force is still being applied to said setting sleeve means; and said retainer means comprises slips, and spaced apart ramps disposed on opposite sides of said slips; said ramps being movable into a more closely spaced relationship to expand said slips into said engagement with said conduit; said ramps being connected with a locking ratchet for locking said ramps into a set position; said retainer setting means is disposed below said retainer means and includes an inverted frustum, and a plurality of collet fingers for moving said ramps more closely together, said collet fingers being supported on said inverted frustum before setting; a releasable spacer means for retaining said inverted frustum and said collet fingers in spaced relationship; said spacer means being releasable under sufficient differential force to allow relative movement between said inverted frustum and said collet fingers such that after said slips are set said collet fingers can traverse along said inverted frustum and contract their external diametral dimension sufficiently to pass upwardly through an internal bore of said seal sub and said set liner for removal from said conduit in said well.

3. The combination of claim 1 wherein there is included a large bore seal unit that conformingly and sealingly fits within said bore of said seal sub and has a portion that seals contiguous said sealing surface.

4. The combination of claim 3 wherein said large bore seal unit comprises a body having a longitudinally extending aperture penetrating therethrough.

5. The combination of claim 4 wherein said liner has a top portion integrally connected with said body portion and said top portion has an inner inverted frusto-conical section to form a stabbing section to facilitate entry of other elements into said liner once emplaced in said well.

6. A combustion packer assembly for a conduit in a well penetrating subterranean formations and having a given diameter comprising:

7. The combination of claim 6 wherein said retainer means comprises slips, and spaced apart ramps disposed on opposite sides of said slips; said ramps being movable into a more closely spaced relationship to expand said slips into said engagement with said conduit; said ramps being connected with a locking ratchet for locking said ramps into a set position effected by movement of the ramps more closely together.

8. The combination of claim 7 wherein there is included a large bore seal unit and said conduit; said annular body portion and said retainer means have been expanded into their respective engagements with said conduit; said seal sub has its longitudinally extending internal sealing surface receiving in sealing relationship said large bore seal unit and said annular body portion sealingly and frictionally engages said conduit and said retainer means positively mechanically engages said conduit to provide sufficient force to support the weight of said packer in said well and resist being displaced by pressure acting on said combination.

9. The combination of claim 6 wherein said large bore seal unit comprises a body having a longitudinally extending aperture penetrating therethrough.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to apparatus for use in wells penetrating subterranean formations. More particularly, it relates to liners and seal subs, and packers and combinations of apparatus employing the same in casing or tubing in an oil well or the like.

2. Description of the Prior Art

As described in co-pending U.S. Pat. applications Ser. No. 166,066, now U.S. Pat. No. 3,712,376, entitled "Conduit Liner for Well Bore and Method and Apparatus for Setting Same" and U.S. Pat. Ser. No. 166,032, entitled "Conduit Liner for Well Bore," inventers Harrold D. Owen, Wayne O. Rosenthal and James Douglas Young, the prior art is replete with practical and impractical liners, with and without seal subs and packers. A wide variety of different types of packers are also known in the prior art. Illustrative of the principle of the packers are the so-called "production packers."

Production packers are used in subterranean wells today, primarily to form a seal between the well casing and the well tubing. The seal allows production and workover operations to be carried out in the well. Production packers are generally classified as either retrievable or permanent. The retrievable packers can be pulled readily out of the well, if not too badly corroded; but may not be as desirable and dependable as the permanent packers. The permanent packers heretofore have been required to be drilled out or otherwise destroyed to get them out. Most frequently, the need to remove a permanent packer is caused by having to pass a large diameter special purpose tool down the well to a point below where the permanent packer is set. Presently available permanent packers do not provide large enough openings through them to allow special pupose tools to pass therethrough.

Moreover, many wells need to employ larger diameter tubing to effect maximum production rates for most economical operation. The presently available packers do not always provide a bore size as large as required for the diameter of the tubing needed for most efficient production. where each fraction of an inch of increased bore size pays large dividends, presently available packers are lacking.

Moreover, presently available packers employ the use of various approaches to prevent the extrusion and destruction of their expansible-type sealing elements when the packer is subjected to high differential pressures. The difficulties with the expansible type sealing elements is further complicated when the packer is required to withstand high temperatures; for example, 350° F or more. Setting packers to withstand the high pressure differential and the high temperatures has been heretofore particularly expensive.

Accordingly, it is an object of this invention to provide apparatus that can be employed to set a production packer that has an internal bore that is large enough to obviate the disadvantages of the prior art devices and, particularly, to allow passage of large diameter special purpose tools and large diameter tubing.

It is also an object of this invention to provide a packer effecting the foregoing object and also virtually eliminating the extrusion of an expansible sealing element by greatly reducing all possible extrusion space.

It is also an object of this invention to provide an apparatus for setting a large bore packer that effects the foregoing objects and also is suitable for use at the high temperatures mentioned hereinbefore primarily because it employs a metal-to-metal seal with the conduit in the well.

These and other objects will become apparent from the descriptive matter hereinafter, particularly when taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic elevational view of the apparatus in accordance with one embodiment of this invention in a casing in a well penetrating subterranean formations.

FIG. 2 is a fragmented longitudinal sectional view of upper and lower portions of the apparatus of FIG. 1, showing the apparatus in its preset position.

FIG. 3 is a side elevational view, partly in section, showing a large bore packer, or seal unit, in accordance with another embodiment of this invention.

FIG. 4 is a side elevational view, partly in section, showing the packer, comprising the liner, seal sub, and retainer means of FIGS. 1 and 2 in the set position in the conduit in the wellbore.

FIG. 5 is a side elevational view, partly in section, showing the seal unit of FIG. 3 emplaced in the set packer assembly of FIG. 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 illustrates a setting tool device 11 having a packer assembly 12; comprising an expansible liner 13, a seal sub 15 and retainer means 17; suspended from a wireline 19 at a given depth in a section of casing 21 in a wellbore 23 penetrating subterranean formations 25. A collar locator and cable head assembly 27 is ordinarily included to facilitate accurate emplacement of the liner and seal sub and withdrawal of the setting tool device.

The setting tool device 11 is illustrated in the aforementioned U.S. Pat. applications Ser. Nos. 166,032 and 166,066 and is described in detail in U. S. Pat. No. 3,186,485, "Setting Tool Device," Harrold D. Owen. Reference is made to those documents for a detailed description of the construction and operation of the setting tool. Broadly, the setting tool device 11 is a type of force generating means wherein a piston assembly and a cylinder assembly are powered for movement relative to each other by an ignitable charge in the tool. Briefly, setting tool device 11 includes a fluid actuated means comprising a head assembly including igniter means; a cylinder assembly; and a piston assembly within the cylinder assembly, with the piston assembly being slidable relative to the cylinder assembly; and means including a combustion chamber adapted for receiving a combustible material powder charge and disposed within the cylinder assembly for imparting relative movement to the cylinder assembly and the piston assembly. When the setting tool device 11 is connected with a swage means 31 and a retainer setting means 77, as described hereinafter, this relative movement is translated into a movement of the swage means 31 upwardly through the liner 13 and a movement of the retainer setting means 77 upwardly through the retainer means 17; movement of both of which is opposed by a setting sleeve means 29.

For ease of explanation, the setting tool device 11 is illustrated in FIG. 2 as having its piston assembly connected with the swage means 31 and its cylinder assembly connected with the setting sleeve means 29. Adapter means are available to effect the converse connection in which the cylinder assembly is connected with the swage means 31 and the piston assembly is connected with the setting sleeve means 29 if desired.

The packer assembly 12 is accurately positioned at a given depth; for example, by use of collar locator 27. Thereafter, the setting tool device 11 is activated to emplace the liner 13, seal sub 15 and retainer assembly 17 at the desired depth.

Referring to FIGS. 2 and 4, the liner 13 includes an annular body portion 33 having interior and exterior surfaces 35 and 37 that define cylinders that are at least partially coextensive. The body portion 33 has an outside diameter less than the diameter of the casing, or conduit; has sufficient malleability for and is adapted for being expanded to conformingly engage the casing; and has a wall thickness sufficient to effect a wall after expansion capable of withstanding the differential pressure between the inside and the outside of the liner 13. The body portion 33 of the liner 13 has a modulus of elasticity in compression sufficient to retain tight frictional engagement with the conduit 21 after being expanded thereagainst and prevent being displaced upwardly or downwardly by forces normally expected to be imposed on the liner 13.

As illustrated, the liner 13 contains suitable seal means 49 for ensuring a fluid impermeable connection between it and the casing 21. For example, the seal means 49 may comprise a plurality of o-ring type seals disposed in grooves 51 extending peripherally around the liner 13.

A connector means 39 is connected at its one end with the body portion 33 and at its other end with the seal sub 15. The connector means 39 has an expansible portion 41. The expansible portion 41 may be integrally formed with the liner 13; may be affixed by any suitable expansible joints; for example, it may be thermally joined thereto, as by welding or silver soldering; all as described in the aforementioned copending U.S. Pat. applications Ser. Nos. 166,066 and 166,032. As illustrated herein, however, the top of the connector means 39 and the bottom of the body portion 33 are connected by means of threaded connection 43, FIG. 4, to facilitate interconnection of the liner 13 and the seal sub 15. Suitable seal means 45, such as an o-ring, is provided in conjunction with the threaded connection 43 to ensure sealing even after expansion of the expansible portion 41 and the liner 13 into their set position engaging the conduit 21. Similarly as described with respect to the connection between liner 13 and the connector means 39, the connector means 39 may be connected with the seal sub 15 by any suitable interconnection. As illustrated, the connector means 39 is formed integrally with the seal sub 15. Any of the other types of interconnection delineated hereinbefore, or other suitable interconnection means, may be employed, if desired.

The seal sub 15 has a seal surface 53 defining an internal bore and extending longitudinally thereof. The seal surface 53 is provided with a smooth finish for sealing engagement with a seal nipple, packer or the like that it is to sealingly receive.

The retainer means 17 are settable for retaining the seal sub at a set depth by supplementing the force exerted by the annular body portion 33 when it is expanded into the tight frictional and sealing engagement with the conduit 21. The retainer means 17 has a preset outside diametral dimension less than the diameter of the conduit 21 and is expansible radially outwardly into positive mechanical engagement with the conduit 21 upon setting at the desired depth. The retainer means 17 is lockable into its expanded and set position. Specifically, the retainer means 17 comprises a plurality of pairs of slips 55 held in position intermediate spaced apart ramps 57 and 59 via suitable means, such as C-ring 61. Ordinarily, the ramps 57 and 59 comprise frusto-conical sections, that are commonly referred to as cones, for setting the slips. As illustrated, the cone ramp 57 is an integral part of the seal sub 15 that also has an interiorly extending cylindrical portion 63. The frusto-conical ramp 59 and its body are disposed exteriorly of the interiorly extending cylindrical portion 63 and are movable longitudinally thereof to move the spaced apart cones 57 and 59 more closely together for setting the slips 55. The body actually comprises a lock ring 65 and a force ring 67. The lock ring 65 has interiorly protruding ratchet teeth 69 that co-act with exteriorly extending ratchet teeth 71 to form a locking ratchet for locking the ramps 57 and 59 into a set position when they are moved more closely together to expand the slips 55 outwardly into contact with conduit 21. The lock ring 65 has a pluarlity of slots 73 that are spaced around it and extend longitudinally a short distance to allow the requisite flexibility for the ratchet teeth to engage each other for locking, yet ratchet over each other for movement of the body longitudinally upwardly for setting. The ratchet teeth on the respective interior cylinder 63 as well as on the lock ring 65 are, in fact, continuous and form peripheral rings interiorly and exteriorly of their respective supports. The teeth rings have inversely inclined mating surfaces to prevent slipping of the teeth with respect to each other once they are engaged. Thus, once the retainer means 17 is set, it is locked into position and cannot slip or fail to provide the supplemental support needed for resisting displacement by any unusually large force, such as high differential pressures or high weight imposed on the liner and seal sub assembly.

Referring to FIG. 2, the liner 13, seal sub 15 and retainer means 17 are emplaced adjacent the respective setting elements that are connected with the setting tool device 11 for being lowered into the well to a given depth and set in the casing 21. The liner 13 is disposed adjacent the swage means 31 for being expanded outwardly into tight frictional and sealing engagement with the casing 21 in the well; and is disposed adjacent a setting sleeve means 29 for holding the liner 13 at the desired setting depth against the force of the swage means 31, as the swage means 31 is forced through the liner. As illustrated, the liner 13 is disposed between swage means 31 and the setting sleeve means 29. Expressed otherwise, the swage means 31 is disposed below the liner 13 for moving upwardly through and expanding the liner outwardly into sealing contact with the casing 21. The external dimensions of the swage means 31 are pre-selected in accordance with the internal dimensions of the casing 21 and the diameters and wall thickness of the liner 13 to effect the necessary frictional engagement and the necessary thickness of the wall of the liner 13 after expansion into frictional and sealing engagement with the casing 21. As illustrated, the swage means 31 has a frusto-conical section 75 to facilitate upward passage through the liner 13 and expansion outwardly thereof. If desired, the frustoconical section 75 may have an arcuate cross sectional profile for greater strength. The swage means has an exterior contour capable of generating a smooth, cylindrical interior surface and having the requisite strength to expand the liner 13 out against the conduit 21 with the force available in the force generating means.

A retainer setting means 77 is provided for expanding the retainer means 17 into the requisite positive mechanical engagement with the conduit 21 for setting at the desired depth. The retainer setting means 77 is removable upwardly through the conduit after the liner 13 and the setting means 17 have been set. Specifically, and as illustrated, the retainer setting means 77 is disposed below the retainer means 17 and includes an inverted frustum 79 and a plurality of collet fingers 81 for moving the ramp 59 more closely adjacent the ramp 57 for expanding the slips 55 outwardly into contact with the casing 21. The collet fingers 81 are supported on the inverted frustum 79 before setting such that they engage the force ring 67 for moving it and ramp 59 upwardly relative to ramp 57 and the cylindrical portion 63. A releasable spacer means 83 is provided for retaining the inverted frustum 79 and the collet fingers 81 in spaced relationship. The spacer means 83 is releasable under sufficient differential force between the inverted frustum 79 and the collet fingers 81 to allow relative movement therebetween such that after the slips are set the collet fingers can traverse interiorly along the inverted frustum and contract their external diametral dimension sufficiently to pass upwardly through the internal bore of the seal sub and the set liner for removal. Specifically, the spacer means includes a shear pin 85 screwed into apertures 87 and holding an adapter rod 89 and spacer ring 91 in spaced relationship until sheared. The collet finger 81 are integrally formed with a threaded section, or ring, 93 that engages a threaded portion of the shear ring 91, as illustrated. Roll pin 95 prevents the threaded connection from coming unscrewed while it is being used in the well. Thus, it can be seen that when sufficient force is exerted on the adapter rod 89 to move it upwardly relative to the ramp 57, the lower ramp 59 is moved upwardly to first set the slips into engagement with the conduit 21. Simultaneously, the ratchet lock is engaged by the engagement of the interiorly and exteriorly extending ratchet teeth 69 and 71 to hold whatever position is attained. As the force becomes great enough, due to the interlocking of the collet fingers 81 and the force ring 67 and the upward movement of the adapter rod 89, the shear pin 85 is sheared, allowing the inverted frustum 79 to move upwardly and the collet fingers to slide down the inverted frustum 79 and retract inwardly, and to pass on upwardly through the seal sub 15 and liner 13. As illustrated, the inverted frustum 79 is screwed onto the adapter rod 89 by way of mating threaded connection 97. A lock nut 99 is also screwed onto the threaded portion of the adapter rod 89 to lock the frustum 79 in a predetermined position for correct assembly.

An adapter rod means such as adapter rod 89, FIG. 2, is provided for connecting the swage means 31 and the retainer setting means 77 with a force generating means, such as the setting tool device 11. As indicated hereinbefore, the adapter rod 89 is connected with the retainer setting means 77 at its lower end by threaded connection 97 and shear pin 85; is connected with the swage means 31 via threaded connection 101; and is adapted for connection at its other end with a force generating means for subjecting the swage means 31 and the retainer setting means 77 to a force acting upwardly for pulling them upwardly through their respective liner 13 and retainer means 17.

The setting sleeve means 29 is disposed radially of the central axis of the adapter rod 89. As illustrated, the setting sleeve means 29 encircles the adapter rod 89 and has its lower end portion engaging the top of the liner and being adapted at its upper end portion for connection with the force generating means for opposing upward movement of the liner 13 by transmission of a downwardly acting reaction force from the force generating means.

When the setting tool device 11 is employed as the force generating means, the adapter rod 89 is connected at its upper end with bottom piston 103 of the piston assembly of the setting tool device 11. As described in the aforementioned co-pending U.S. Pat. applications Ser. nos. 166,066 and 166,032, setting tool device 11 also includes a top piston, a top piston connecting rod, a top piston extension rod, and a firing head surmounted by quick change assembly (not shown). The setting sleeve means 39 is connected with the bottom cylinder 105 of the setting tool device 11. The cylinder assembly of the setting tool device 11, as described in the above-mentioned applications, also includes a top cylinder and a top sub (not shown). As described also in U.S. Pat. Ser. No. 166,066, a shear plug, having a predetermined shear value, is threadedly inserted into matched holes in an upper cylindrical portion and a lower body portion. Upon ignition of the ignitable charge in the setting tool, the shear plug is sheared and a force generated to pull the swage means 31 upwardly through the liner 13, and to pull the retainer setting means 77 upwardly through the retainer means 17. Movement of the liner 13 and the seal sub 15 upwardly is opposed by the downwardly acting reaction force via the cylinder assembly and bottom cylinder 105 and setting sleeve means 29. Specifically, the setting sleeve means 29 expandably engages the top of the liner 13 by expander means; such as flexible spring fingers 107. The flexible spring fingers are ordinarily of steel. The flexible spring fingers 107 retain the liner 13 in place during setting but are adapted to flex outwardly to allow passage of the swage means 31 therethrough, and spring back into position after the swage means 31 has passed therethrough.

To allow the flexible spring fingers to transmit the reaction force and oppose the force pulling the swage means 31 through the liner 13, as well as allow the retainer setting means 77 to set the retainer means 17, an expander support ring 109 is employed in the setting sleeve means 29. The expander support ring 109 is held in place adjacent the liner 13 and within the flexible spring fingers 107 with a shearable means; such as, shear pins 111; for supporting the flexible spring fingers 107 during the interaction of the large force and reaction force pulling the swage means 31 through the liner 13 and, subsequently, shearing to allow the expander support ring to move upwardly with the swage means 31. The expander support ring 109 has an annular shoulder 113 for conformingly engaging a shoulder portion 115 of the flexible spring fingers 107. The expander support ring 109 is adapted to be picked up by the swage means 31 as it moves upwardly and to be moved upwardly longitudinally within the setting sleeve means 29 after the swage means 31 has passed through the liner 13 and sheared shear pins 111. The setting sleeve means 29 has concentric interior space for receiving the swage means 31 and allowing it to pass upwardly completely out of the liner 13.

In operation, the packer assembly 12 is placed in the well by the following procedure. The packer assembly and its setting apparatus, setting tool and any accessory equipment are inserted through conventional well head and lubricator equipment and lowered to the desired depth on wireline 19. As indicated hereinbefore, once the liner is accurately positioned at the desired depth in the conduit in the well, the force generating means comprising an ignitable charge in the setting tool is actuated; thereby, normally in a single stroke, pulling the swage means 31 and the retainer setting means 77 upwardly through, respectively, the liner 13 and the setting means 17. Upward passage of the swage means 31 expands the liner 13 outwardly into physical and sealing contact with the conduit 21 with sufficient force to retain it in place. Upward movement of the retainer setting means 77 also sets the retainer means 17.

In detailed operation, as relative longitudinal movement starts to occur between the liner 13 and the swage means 15 in response to the upwardly and downwardly acting forces from the force generating means, the liner is forced outwardly to engage the casing 21. The engagement of the liner 13 with the casing 21 stops downward movement of the liner, obviating the need for an anchor of any sort; and regardless of whether or not the setting means 17 have been set prior to or after the liner 13 is expanded into engagement with the conduit 21. Thereafter, for all practical purposes, the force of the setting tool is directed to pulling the swage means 15 upwardly through the liner 13 which has been immobilized in tight fritctional and sealing engagement with the casing 21.

As the swage means 31 moves out of the top portion of the liner 13, it engages the expander support ring 109, shearing shear pin 111 and moving the expander support ring 109 upwardly. The spring fingers 107 move outwardly to allow the swage means 31 to pass therethrough, retaining engagement with the top edge of the liner 13.

The detailed operation of the setting tool device 11 in moving the swage means upwardly relative to the liner 13 is explained in the aforementioned U.S. Pat. application Ser. No. 166,066 and need not be repeated in detail herein. It is sufficient to note that upon firing of the charge, there is relative movement, after shearing of the shear pin, between the piston assembly and the cylinder assembly and this relative movement is translated into relative movement of the shear means 31 and the retainer setting means 77 with respect to their respective liner 13 and retainer means 17. Considering specifically the setting of the retainer means 17, upon initial movement in the illustrated embodiment the force ring 67 is moved upwardly by collet fingers 81 to move the ramps, or cones, 59 upwardly and set slips 55 into engagement with the interior walls of the conduit. Simultaneously, the ratchet lock is engaged to hold this set position. When sufficient force has been reached to shear the shear pin 85, it shears, moving the inverted frustum 79 upwardly, allowing the collet fingers to move down its slope and retract their outside diametral dimensions sufficiently to pass upwardly within force ring 69 and interiorly of the retainer means 17.

As the swage means 31 moves upwardly concomitantly with the upward movement of the adapter rod 89 to which it is connected, it expands the liner 13 outwardly into engagement with the conduit, as described Following the setting operation, the setting tool device 11, the swage means 31, the retainer setting means 77, the setting sleeve means 29 and accessories are removed from the well, leaving the packer assembly in place. The packer assembly has an unusually large bore penetrating longitudinally through the seal sub 15 for receiving a large bore seal unit or seal nipple therewithin.

The compositions of the liner in its preferred form, as well as other forms, are delineated at length in the above-referenced U.S. Pat. applications Ser. nos. 166,066 and 166,032. Briefly, the liner may be formed of any material having the requisite malleability and modulus of elasticity in compression. Ordinarily, the liner will be a metallic liner. For example, alloys of copper, magnesium, aluminum or iron may be employed. The soft steels form satisfactory liners, since they have the requisite properties and do not set up any galvanic cells regardless of the fluid in the conduit or outside the conduit in a well. A surprising and particularly preferred material of construction is commercially pure iron such as is employed in magnetic ingots for making iron cores for electromagnets, relays and the like. The commercially pure iron is highly refined open hearth grade of low carbon, low manganese iron. It has less than 1 percent by weight of alloy constituents, or other elements, and is described in detail in the above-referenced U.S. Pat. application Ser. No. 166,032. The liner remaining emplaced in the casing will have uniform crystallographic structure, since it has been substantially uniformly expanded outwardly to engage the casing 21 into which it is emplaced. Also, the liner will have a smooth bore that will serve to seat satisfactorily against other elements, although this portion is not critical, since the interior seal surface 53 of the seal sub 15 will ordinarily be employed for sealingly receiving its elements; such as, a large bore seal unit.

FIG. 3 illustrates a large seal unit 117 that is suitable for being emplaced within the packer assembly 12. As employed herein, the term "seal unit" includes a packer, a seal nipple, and the like for sealing interconnection with another element, such as a atring of tubing. Suitable seal nipples have been described in the above referenced U.S. Pat. application Ser. No. 166,066. The seal unit 117 has suitable seal means 119 disposed peripherally around a portion of its exterior surface for sealingly engaging the seal surface 53 of the seal sub 15. The seal means may be disposed in suitable grooves 121 extending peripherally around the body of the seal unit 117, similarly as described with respect to liner 13 hereinbefore. As illustrated, the seal unit 117 has, at its top end, suitable receiving means; such as upset tubing threads 123 in collar 125 for receiving mating threaded connection of tubing or the like for production of fluids from the subterranean formation. As illustrated, the collar 125 is threadedly connected with the top end of the seal unit 117.

Referring to FIG. 5, the seal unit 117 is sealingly inserted into the seal sub 15 with the bottom of collar 125 resting upon the internal wall of the inverted frusto-conical stabbing section 127 of the liner 13. The seal means 119 sealingly engages the seal surface 53 to form a fluid impermeable block. Thereafter, production fluids may be produced to the surface through the production conduit, such as tubing 129, the tubing 129 having been previously threaded into the tubing threads 123.

The details of construction of the parts of the setting tool, the swage means and other elements known to the prior art have been described in the aforementioned U.S. Pat. application No. 166,066 and reference is made thereto for the details. For example, fluid flow passageways may be provided through the respective means to facilitate moving rapidly down a wellbore through fluids in the conduit 21, if desired.

The particular desirable features of liner 13 and its setting apparatus have been delineated at length in the above-referenced applications, such as U.S. Pat. Ser. No. 166,066, and need not be repeater herein. It is sufficient to note herein that the additional support effected by setting means 17 increases the flexibility of the liner and seal sub assembly once emplaced in the well and allows it to resist being displaced upwardly or downwardly against much greater force than with the liner alone.

From the foregoing it can be seen that this invention provides the objects delineated hereinbefore and provides apparatus that can be employed in setting a large bore seal unit that has a large internal bore sufficient to obviate the disadvantages of the prior art and allow use of large diameter production conduits, as well as allow passage of large diameter special tools therethrough without requiring a drilling out of the packer assembly.

Although this invention has been described with a certain degree of particularity, it is underatood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of this invention.