US3520361A

US3520361A - Well packer with slip and drag block assembly

Info

Publication number: US3520361A
Application number: US792964*A
Authority: US
Inventors: William R Lewis
Original assignee: KIVA CORP
Current assignee: Schlumberger Technology Corp; KIVA CORP
Priority date: 1969-01-22
Filing date: 1969-01-22
Publication date: 1970-07-14
Anticipated expiration: 1987-07-14

Description

w. R. LEWIS 3,520,361

WELL PACKER WITH SLIP AND DRAG BLOCK ASSEMBLY July14, 1970 5 Sheets-Sheet 1 Filed Jan. 22, 1969 INVENTOR. WML/AM @e ew/"5 BY I, 4]/

WELL PAGKER WITH SLIP AND DRAG BLOCK ASSEMBLY Filed Jan. 22, 1969 W. R. LEWIS July 14, 1970 3 Sheets-Sheet 2 n INVENTOR. l/l//LL/AM P 5- PA/EKS July 14, 1970 w. R, Ewls 3,520,361

WELL PACKEH WITH SLIP AND DRAG BLOCK ASSEMBLY Filed Jan. 22, 1969 3 Sheets-Sheet :S

ELEE United States Patent O 3,520,361 WELL PACKER WITH SLIP AND DRAG BLOCK ASSEMBLY William R. Lewis, Wichita Falls, Tex., assignor to Kiva Corporation, Wichita Falls, Tex., a corporation of Texas Filed Jan. 22, 1969, Ser. No. 792,964 Int. Cl. E21b 33/12 U.S. Cl. 166-134 20 Claims ABSTRACT OF THE DISCLOSURE A down-hole tool for use in oil wells and which in.- cludes upper and lower resilient packing sleeves mounted on a tubing string and each compressible between a fixed collar on the tubing string and a slip and drag block assembly which is axially movable on the tubing string. Each of the packing sleeves is wire reinforced to` aid return of the sleeve to an uncompressed condition. The slip and drag block assembly includes a connector sleeve bidirectionally movable on the tubing string, and carrying slip retainer elements at opposite ends thereof. A set of slips is mounted on each retainer element and each of the slips carries a separately formed, independently movable drag block.

BACKGROUND OF THE INVENTION Brief description of the prior art Many types of well tools have been previously proposed and used for selectively anchoring some type of well treating device at a desired location in the casing of an oil well. Such anchorage is frequently obtained by utilizing wicker carrying clips which are forced against the well casing by sequentially rotating, and then moving axially, a tubing string upon which the slips are mounted for limited movement relative thereto. In the course of setting the slips, the tubing string is movable independently of the slips due to their association with drag blocks or drag shoes which frictionally engage the casing and retard movement of the slips relative to the tubing. It is the usual practice to construct each slip and drag block as an integral unit pivotally mounted on the tubing string with a suitable spring being utilized to yieldingly bias the drag block into engagement with the casing.

Slips including anchoring assemblies of the type described are often utilized in conjunction with expandable packing sleeves or cups which are carried on the tubing string and are made of rubber or other resilient material. The packing sleeves are caused to expand against the casing and seal or pack it off as a result of compression between a shoulder, collar or the like secured to, and I movable with the tubing string, and the slips, which can undergo limited axial movement relative to the string. Often the same movement of the tubing string which forces the wickers of the slips to bite into the casing also expands the packing sleeves against the casing to pack oit the well.

Brief description of the present invention The present invention is an improved well tool for selectively anchoring and expanding packing rings at desired locations in a Well casing, with the tool providing independently set, dual packing rings which can be set to pack off the well bore against a pressure differential acting across the tool in either direction. Broadly described, the tool comprises a tubing string having a pair of compression collars secured therearound and axially spaced therealong. To each compression collar, a metal reinforced packing sleeve assembly is secured and surrounds the tubing string and projects axially toward the other collar and packing sleeve assembly. A slip and drag shoe assembly is mounted on the tubing string between packing sleeve assemblies, and within the limits of movement imposed by an H-shaped slot in which it is keyed, is movable axially and rotatably on the tubing string. The slip and drag shoe assembly includes sleeve means cooperating with the H-shaped slot and carrying at opposite ends thereof, sets of radially displaceable slips which can be wedged against the walls of the casing by engagement with a portion of the adjacent packing sleeve assembly. Each of the slips in each set carries a separately formed, independently movable drag block which is radially movable with respect to the slip.

The well tool of the invention achieves several irnportant objects and possesses advantages over generally similar anchoring and packing tools as a result, in large part, of the construction of the drag blocks and slips as separate units, and of the metal reinforced construction of the packing sleeves. Thus, by making the drag blocks separately movable with respect to the slips, the tool can be utilized in many different well casings exhibiting a relatively great variation in internal diameter. This construction also results in improving the economics of tool manufacture and fabrication, since the drag blocks need not be hardened by the procedure of hardening required to bring the wickers of the slips to a suflicient hardness to bite into the casing when the tool is set or anchored. The reinforcement of the elastomeric portion of the packer sleeve assembly with resilient metal improves the elastic memory of this portion of the assembly, makes the tool easier to` release from a packed off status and extends the elfective, trouble-free operating life of the tool.

In additon to these advantages and objects, other objects and advantages will become apparent as the following detailed description of the invention is read in conjunction with the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a View partially in section and partially in elevation showing the upper portion of the well tool of the invention as it appears when being lowered in a well casing.

FIG. 1B is a view partially in section and partially in elevation showing the lower portion of the well tool of the invention which is disposed immediately below that portion thereof shown in FIG. 1A.

y FIG. 2 is a sectional View taken along line 2 2 of FIG. 1.

FIG. 3 is a view similar to the view of FIG. lA, but showing the tool anchored in place and the upper packing sleeve assembly expanded to pack off the casing against a relatively high down-hole pressure.

FIG. 4 is a perspective view of one of the slip retainer elements utilized in the well tool of the invention.

FIG. 5 is a perspective view of one of the slip elements used in the well tool of the invention and showing a drag block mounted in operative position thereon.

FIG. 6 is a view similar to FIG. 1B illustrating a modified construction of a portion of a well tool, and illustrating the lower packer sleeve being in a set position in a casing.

FIG. 7 is a view similar to FIG. 6 and illustrating the FIG. 6 structure in another operating position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring initially to FIGS. lA and 1B of the drawings, the well tool of the invention is designated generally by reference numeral 10, and is shown as it appears when it is being lowered in a well casing 12. The overall combination of the well tool may be described as including a tubing string 14 which includes an upper tubing section 16 and a lower tubing section 18. The upper and

lower tubing sections

16 and 18 are threadedly connected to

special subs

20 and 22, respectively. Each of the

subs

20 and 22 carries a radially outwardly extending, fixed backup collar 24 and the

subs

20 and 22 are connected to opposite ends of an elongated central tubing section 26.

Bonded, or in any other manner suitably secured, to the lower end face of the upper fixed collar 24 is a resilient packing sleeve 28 which, in the illustrated embodiment, constitutes a generally cylindrical body of elastomeric material, such as rubber or the like. It will be noted that the packing sleeve 28 has an external diameter slightly less than the internal diameter of the casing 12 in the relaxed status which characterizes the packing sleeve during its traversal of the casing. Ernbedded in the body of the resilient packing sleeve 28 is a helical metallic spring element 30 which extends from the upper portion of the packing sleeve to the lower portion thereof. The packing sleeve 28 is not bonded to the central tubing secton 26 and is free to move axially with respect thereto in undergoing cornpression and expansion. At its lower end, the packing sleeve 28 is bonded to a frusto-conical metallic slip expander element 32 which is also freely slidable on the central tubing section 26. The expander element 32, packing sleeve 28 and metallic spring element 30 are, for convenience, hereinafter referred to as the upper packing sleeve assembly, designated generally by reference numeral 33.

Before discussing the slip and drag block assembly, it will be well to point out that the well tool of the invention includes a lower resilient packing sleeve assembly 34 which is constructed substantially identically to the upper packing sleeve assembly 33 which has been described. Thus, there is secured to the fixed collar 24 of the special sub 22 connected between the lower tubing string 18 and the central tubing string 26, an elongated, generally cylindrical packing sleeve 35 of elastomeric material which is freely slidable on the central tubing section 26 and has embedded therein a helical resilient spring element 36. The lower packing sleeve 34 is also bonded at its upper end to a frusto-conical metallic slip expander element 38 which is freely slidable in an axial direction on the central tubing section 26. It may thus be perceived that the construction of the metal reinforced packing sleeve 28 located in the upper portion of the well tool is substantially the same as the metal reinforced packing sleeve located in the lower portion of the well tool, and that their operations are substantially identical will clearly appear from the discussion of the overall operation of the tool hereinafter set forth.

The slip and drag block assembly constituting an important portion of the present invention is centrally located within the well tool of the invention and is designated generally in the drawings by reference numeral 40. The slip and drag block assembly 40 includes an elongated connector sleeve 42 which is internally threaded at its upper and lower ends for connection to upper and lower

slip retainer elements

44 and 46. It will be noted that at the opposite ends of the connector sleeve 42, the sleeve carries axially extending, annular flanges 47 which define bores 48 in the opposite ends of the connector sleeve.

The connector sleeve 42 has extended through a medial portion thereof a slot engaging lug 49 which projegcts radially inwardly into an H-shaped slot, sometimes referred to in the art as a I-slot, and designated generally by reference numeral 50. The H-slot 50 is formed in a built-up, radially outwardly projecting mandrel portion 52 formed on the central tubing section 26. Instead of the central tubing section 26 being built up to form the mandrel portion 52, a suitable sleeve carrying the H-slot 50 may be separately formed and secured in position around the central tubing section 26 if this should be desired. It will be noted that the H-slot 50 includes a transverse or laterally extending potrion 50a which interconnects a relatively short leg 5019 and a relatively long leg 50c With the

legs

50b and 50c extending axially along the central tubing section 26. The connector sleeve 42 has formed therethrough near its upper and lower ends, a plurality of vent ports S4 which function to vent or bleed any fluids which may become entrapped between the central tubing section 26 and the connector sleeve 42 to the annulus between the well tool and the casing 12.

The

slip retainer elements

44 and 46 which are threadedly connected to the opposite ends of the connector sleeve 42 each have formed thereon an annular flange 56 carrying external threads which engage the internal threads in the connector sleeve. Each of the

slip retainer elements

44 and 46 then further includes an elongated axially extending tubular element 58 upon which are mounted a plurality of circumferentially spaced, axially extending, radially protuberant fingers 60. The fingers 60 are characterized in having a cross-sectional configuration resembling a truncated sector of a circle. In other words, the opposite side faces 60a and 6011 of the axially extending fingers 60 converge toward the axis of the central tubing section 26, and the radially outer face 60C of each of the fingers is arcuate. At its upper end, each of the fingers 60 carries a radially outwardly extending retaining lip 62 with the lingers and their respective retaining lips being circumferentially spaced at substantially equal intervals around the sleeve 58 to which they are secured.

Each of the

slip retainer elements

44 and 46 carries around the outer periphery thereof, a plurality of circumferentially spaced slips designated generally by reference numeral 66. The configuration of each of the slips 66 is best illustrated in FIG. 5 of the drawings. As here shown, it will be noted that each slip 66 includes an elongated shank portion 68 which is formed integrally with a head portion 70 at one end thereof which carries a series of outwardly facing serrations or wickers 71.

Secured to the shank portion 68 are a pair of axially spaced, L-shaped drag

block retaining toes

72 and 74. The drag

block retaining toes

72 and 74 face toward each other and have arcuate under surfaces which engage the mating arcuate upper surfaces of the opposite end portions 78 of a drag block 80. Each drag block 80 is resiliently biased radially outwardly with respect to its respective slip 66 by a pair of helical springs 82 so that the end portions 78 thereof bear against the under side of the

drag block toes

72 and 74. The helical springs 82 which are used to resiliently bias the drag block 80 away from the shank portion 68 of the slip 66 enter counter-bores (not visible) formed in the lower side of the drag block, and are retained in the illustrated position by a pair of headless screws which are partially threaded into the shank portion 68 of the slip 66.

Projecting in an axial direction from a central portion of the drag -block retaining toe 72 is a retainer lip 86 which is arcuate in a transverse sense with respect to the slip 66, and which projects in an axial direction into the respective bore 48 formed in the end of the connector sleeve 42. As shown in FIGS. 1A and 1B, the retainer lip 86 bears against one end of a helical spring 90 which is positioned between the respective retainer lip and the respective

slip retainer element

44 or 46. In a slot or space 91 formed between the drag block retaining toe 74 and the head portion 70 located at one end of each slip 66, a slip engaging ring 92 is extended around the well tool 10 and bears against the outer faces 60C of the several elongated, `axially extending fingers 60 of the respective

slip retainer elements

44 and 46. The slip engaging ring 92 thus restrains the radially outward movement of the slips y66 with respect to the central tubing section 26, though permitting limited movement in this direction when the Slips are set to an anchoring position as hereinafter described.

The relative arrangement of the slips 66, the slip retainer element 44, and the slip engaging ring 92 is perhaps best illustrated in FIGS. 1A and 2. In the latter view, the slip engaging ring 92 is illustrated by a dashed line since it is actually' located below the plane in which the section is taken.

OPERATION OF FIGS. 1-5

In the operation of the well tool of the invention, the tool is first assembled in the status illustrated in FIGS. lA and 1B. This entails setting the connector sleeve 42 upon the central tubing section 26 so that the lug 49 is positioned in the portion 50b of the H-slot 50. Also, -prior to running the well tool 10 in the casing 12, the drag blocks 80 will have been forced into their illustrated positions on the slips 66 so that they are retained in this slip mounted position by the slight interlock resulting from the curvature of their end portions as these end portions engage the arcuately shaped drag

block retainer toes

72 and 74 under the bias of the helical springs 82. The tool 10 is then connected in the manner illustrated to the upper tubing section 16 and the lower tubing section 18 and the tubing string and tool are run into the well.

Due to the location of the lug 49 in the short leg 50b of the H-slot 50, the -connector sleeve 42 is prevented from moving upwardly or downwardly relative to the central tubing section 26 to an extent suicient to permit the heads 70 of the slips 66 to engage either the upper or the lower

packing sleeve assemblies

33 and 34. As the tubing string with the well tool 10 connected therein is moved down in the casing 12, the drag blocks 80 are biased into contact with the internal wall of the casing by the helical springs 82. The helical springs 82 function to permit considerable radially inward movement of the drag blocks 80 so that casings of widely varying diameters may be traversed by the well tool without loss of frictional contact between the drag blocks. The frictional drag on the casing 12 by the drag blocks 80 will result in the lug 49 being moved into the upper end of the portion 50b of the H-slot 50, but as has been indicated, such axial movement of the lug and the associated connector sleeve 42 is insufficient to permit the heads 70 of the slips 66 to move into contact with the slip expander element 32 of the upper packing ring assembly 33. Thus, the wickers 71 of the several slips 66 located in the upper portion of the tool remain out of engagement with the casing as the tool is being lowered.

Let it be assumed that it is desired to use the well tool 10 for the purpose of packing off the well bore against an excessive pressure acting downwardly from above the tool. In this instance, the tubing string is lowered to the point where the tool 10, and more specifically, the upper packing ring assembly 33, is at the location where it is desired to pack off the casing 12. The tubing string is rotated in a counterclockwise direction as viewed in FIG. 1A so as to move the lug 49 from the portion 50b of the H-slot through the laterally extending portion 50a into the portion 50c. To effect this change in the relation of the lug 49 to the H-slot 50 will require that the tubing string initially be pulled upward slightly so that the fric tional drag imposed on the slip and drag block assembly by the drag blocks 80 cause the connector sleeve 42 and lug 49 thereof to shift downwardly relative to the tubing string and the built-up portion 52 carried thereon. Concurrently with this slight upward movement, the tubing string is rotated so that the lug 49, in remaining relatively stationary due to the contact of the drag blocks 80 with the casing 12, will move through the transverse portion 50a of the H-slot and into the axially extending portion 50c.

When the lug 49 reaches this position, the tubing string is then moved downwardly in the casing 12. Due to the frictional resistance to downward movement of the slip CFI and drag block assembly 40 offered by the drag blocks 80 in their contact with the casing 12, the lug 49 will be moved upwardly in the portion 50c of the slot 50 as the tubing string moves downwardly relative to the slip and drag block assembly. Downward movement of the tubing string carries with it, the upper packing sleeve assembly 33 which is secured to the xed collar 24 of the special sub 20. Thus, the metallic slip expander element 32 is brought into contact with the inclined inner surfaces of the heads of the several slips 66 located in the upper portion of the well tool, and the downward movement of the expander element 32 against the slips forces the heads '70 outwardly in a pivotal movement about one end of the shank portion 68 of each slip and against the resilient 'bias of the springs 90. The wickers 71 on the heads 70 of the several slips 60 carried by the upper slip retainer element 44 are thus caused to bite into the internal wall of the casing 12, and to anchor the tool in the casing.

The downwardly acting pressure, coupled with additional downward force imposed on the tubing string results in the elastomeric packing sleeve 28 being placed in compression so that it is expanded against the casing 12 to pack off the well. At the same time as the resilient packing sleeve 28 is compressed and expanded in the manner described, the metallic helical spring element 30 is compressed in resilient deformation. The casing has now been packed off against a relatively high up hole pressure by the tool 10, which is in the anchored and packed off status depicted in FIG. 3.

When it is desired to release the tool from its anchored, packed off status, the tubing string is pulled upwardly to draw with it, the resilient packing sleeve 28 and the metallic slip expander element 32. Since the drag blocks remain in frictional engagement with the internal wall of the casing 12, the slip and drag block assembly 40 moves downwardly relative to the tubing string and to the upper packing sleeve assembly 33 carried thereon, and the slips 66 are released from engagement with the casing. The lug 49 moves downwardly in the portion 50c of the H-slot 50 and, at the proper time, rotation of the tubing string in a clockwise direction results in the lug being moved through the transverse portion 50a into the portion 50b of the slot. The tool may then be extracted from the casing while it is in essentially the same status as that depicted in FIGS. 1A and 1B and as hereinbefore described.

It should be pointed out that an important aspect of the invention resides in the construction of the

packing sleeve assemblies

33 and 34 to include an elastomeric packing sleeve 28 which has embedded therein a metallic resilient reinforcing element, such as the helical spring 30, which improves the elastic memory of the packing sleeve, and assists it in returning to its unstressed or relaxed status. Thus, in some situations of usage of the well tool 10 of the invention, the pressure dilerential across the packing ring may shift so that the higher pressure acts from below the packing sleeve, or the pressure is equalized on opposite sides of the sleeve. In this situation, there may be some tendency for the packing sleeve 28 to remain expanded against the casing 12, even when the tubing string is pulled upwardly to release the slips 66 from engagement with the casing. Moreover, there is some tendency for the exterior surface of the elastomeric packing sleeve 28 to become bonded to the casing 12 where the well tool has been set in the packed off status for a long period of time, The inclusion of the metallic resilient spring element 30 within the body of the elastomer assures that the packing sleeve 28 will return to its relaxed status to permit removal of the tool from the well or a change in the position of the tool within the casing 12.

The well tool 10 of the invention is versatile in its usefulness, in that it may be used with equal facility to pack off the casing 12 against a relatively high down hole pressure which exceeds the pressure above the tool. Where this use is to be rnade of the tool, the lower packing ring assembly 34 is employed in substantially the same manner as has been described in referring to the operation of the upper packing ring assembly 33. Thus, when the location at which the casing is to be packed off has been reached by the lower packing ring assembly 34, the tubing string is pulled upwardly slightly and is then rotated in a counterclockwise direction to move the lug 49 through the trans-verse portion 50a of the H-slot 50 until the lug enters the axially extending portion 50c of this slot.

At this point, instead of forcing the tubing string downwardly in the well to cause the lug 49 to be displaced into the upper end of the portion 50c of the slot 50, the tubing string is pulled upwardly in the casing so that the drag imposed on the drag block and slip assembly 40 causes this portion of the tool to drag behind or lag the upward movement of the tubing string and the

packing sleeve assemblies

33 and 34 carried thereby. Thus, the lug 49 moves into the lower end of the portion 50c of the H-slot 50, and the lower slip retainer element 46 moves downwardly relative to the lower packing sleeve assembly 34. As the lower packing sleeve assembly 34 is pulled upwardly by the upwardly moving tubing string, the slip expander element 38 contacts and wedges the several slips 66 carried by the lower retainer element 46 outwardly toward the casing 12. The wickers 71 of the slips 66 bite into the casing to anchor the tool, and slight continued upward movement of the tubing then causes the elastomeric packing sleeve 35 to be compressed and expanded outwardly against the casing. The well is thus packed olf against a relatively high down hole pressure. Release of the tool from this position is subsequently effected by forcing the tubing string downwardly for a short distance, then rotating it clockwise to move the lug 49 in the H-slot 50 to the original position in the portion 50b of the slot.

EMBODIMENT OF FIGS. 6 AND 7 The modified well tool 10a illustrated in FIG. 6 is of substantially the same construction as the well tool 10 previously described; therefore, only the modifications will be described.

In lieu of the continuous section of tubing 26 extend'- ing through the tool as described in connection with the previous embodiment, the tubing in the tool 10a is made in an upper section 26a and a lower section 26b. The upper section 26a extends from the top of the tool down through the slip assemblies and a short distance into the lower packer sleeve assembly 34. The lower tubing section 26b extends from the lower compression collar 24 upwardly through the lower packer sleeve 35 and through at least a portion of the lower expander 38. The

sections

26a and 26b are threadedly interconnected by lefthand threads 100, such as acme type threads. In a preferred embodiment, the threads 100 are of a length such that the upper tubing section 26a can be disconnected from the lower tubing section 26b upon rotation of the upper section 26a through eighteen turns.

The modified well tool 10a also includes a pulling ring 102 rigidly secured on the upper tubing section 26a immediately above the upper end 104 of the lower tubing section 26b when the tool is in its normal operating position as illustrated in FIG. 6. The pulling ring 102 may be secured on the upper tubing section 26a in any desired manner, such as by threads, and the pulling ring is preferably positioned inside of the upper end portion of the expander 38 in a normal operating position of the tool as shown in FIG. 6.

In the event the lower packer sleeve 35 may become stuck in the casing 12 to such a degree that the lower expander 38 cannot be retracted from the lower slips 66, the

string of tubing 16 (FIG. 1) extending down to the tool is turned to the right a sufficient number of turns to move the pulling ring 102 upwardly into engagement with the sleeve 58 of the lower slip assembly as shown in FIG. 7.

In a typical tool, the tubing string extending down to the tool, and hence the upper tubing section 26a, may be turned through eight turns to move the pulling ring 102 upwardly into engagement with the sleeve 58. Further turning of the tubing string extending down to the tool will further raise the pulling ring 102 to force the sleeve 58 upwardly, and hence retract the slips 66 from the lower expander 38. In a typical tool, the slips 66 may be released from the expander 38 by an additional four turns of the tubing section 26a to the right.

When the slips `66 are retracted from the lower expander 38, it will normally be possible to release the lower packer sleeve 35 by pushing downwardly on the

tubing sections

26a and 26b. However, in the event the lower packer sleeve 35 remains stuck, the string of tubing extending down to the tool may be turned further to the right, such as six additional turns, to completely unthread the upper tubing section 26a from the lower tubing section 26b; whereupon the entire tool 10a, with the exception of the lower packer assembly 34 and lower tubing section 26b, may be removed from the well. As will be understood by those skilled in the art, the materials of construction of the lower packer assembly and tubing section 26b may be constructed of material which can be drilled out in the event that portion of the tool must be left in the well.

From the foregoing it will be apparent that the modied construction shown in FIGS. 6 and 7 provides a safety type joint which will add materially to the safety of use of the tool.

Although preferred embodiments of the invention have been herein described by way of example, changes may be effected in the described and depicted structure without departure from the basic principles of the invention.

What is claimed is:

1. A well tool comprising:

an elonagted tubing string having an upper end and a lower end;

an upper packing sleeve assembly surrounding said tubing string and including a rst packing sleeve distortable radially outwardly from the tubing string;

a lower packing sleeve assembly surrounding said tubing string and spaced axially downwardly on said tubing string from said upper packing sleeve assembly, said lower packing sleeve assembly including a second packing sleeve distortable radially outwardly from the tubing string;

a slip and drag block assembly mounted on said tubing string between said upper and lower packing sleeve assemblies and slidable axially on said tubing string, said slip and drag block assembly comprising:

an upper set of slips adapted for cooperation with said upper packing sleeve assembly to distort said rst packing sleeve radially outwardly from the tubing string and simultaneously move said upper set of slips radially outwardly from the tubing string;

a lower set of slips adapted for cooperation with said lower packing sleeve assembly to distort said second packing sleeve radially outwardly from the tubing string and simultaneously move said lower set of slips radially outwardly from the tubing string;

a drag block mounted on each of at least a portion of the slips in said sets of slips, each of said drag blocks being a separate unit from the respective slip on which it is mounted and movable radially with respect to the tubing string independently of the respective slip on which it is mounted;

sleeve means interconnecting said upper and lower sets of slips; and

slot means on said tubing string receiving a portion of said sleeve means and guiding said sleeve means in limited rotational movement about the axis of said tubing string and in limited bidirectional axial movement along said tubing string.

2. A well tool as defined in claim 1 and further characterized as including a pair of compression collars secured around the tubing string on the opposite sides of the upper and lower packing sleeve assemblies from the slip and drag block assembly and limiting axial movement of the packing sleeve assemblies on the tube string.

3. A well tool as defined in claim 1 wherein each of said packing sleeve assemblies comprises:

a metallic slip expander element facing the nearest adjacent set of slips and slidingly surrounding said tubing string; and

a resilient packing sleeve contacting said metallic slip expander element and surrounding said tubing string on the opposite side of said slip expander element from said slip and drag block assembly.

4. A Well tool as defined in claim 3 wherein each of said resilient packing sleeves has embedded therein, a helical metallic spring element helically surrounding said tub- I ing string.

5. A well tool as defined in claim 1 wherein the sleeve means of said slip and drag block assembly comprises;

an elongated connector sleeve around said tubing string and having an upper end and a lower end;

a slot engaging lug projecting from said connector sleeve into said slot means;

upper and lower slip retainer elements secured to the upper and lower ends of said connector sleeve;

a first slip engaging ring encircling said upper set of slips and cooperating with said upper slip retainer element to retain said upper set of slips around said tubing string and in fixed axial relation to said connector sleeve; and

a second slip engaging ring encircling said lower set of slips and cooperating with said lower slip retainer element to retain said lower set of slips around said tubing string and in fixed axial relation to said connector sleeve.

6. A well tool as deiined in claim S wherein each of said slip retainer elements further comprises:

a tubular element surrounding the tubular string and secured at one end to one end of said connector sleeve;

a plurality of circumferentially spaced, axially extending, radially protuberant fingers on the outer surface of said tubular element and having one of said slips disposed between each adjacent pair of said fingers; and

a radially outwardly extending lip secured to each of said fingers and engaging one of said slip engaging rings.

7. A well tool as defined in claim 5 wherein said slot means comprises a slot-defining rigid body associated with said tubing string and movable therewith, said rigid body defining an H-shaped slot having one of its cross bar-interconnected leg portions substantially shorter than the other leg portion thereof.

8. A well tool as defined in claim 1 wherein each of said slips comprises:

an elongated shank portion;

a head portion formed integrally with the shank portion and having wickers formed thereon; and

a pair of spaced, L-shaped drag block retaining toes secured to said shank portion and retaining one of said drag blocks against movement away from said shank portion.

9. A well tool as defined in claim 8 wherein each of said L-shaped drag block retaining toes has a concavely curved surface;

and wherein each of said drag blocks has convexly curved opposite end portions contacting the concavely curved portions of the drag block retaining toes of the slip upon which it is mounted;

and wherein said well tool is further characterized in including spring means resiliently biasing each of said drag blocks away from the shank portion of the respective slip upon which it is mounted.

10. A well tool as defined in claim 8 wherein the sleeve means of said slip and drag block assembly comprises:

an elongated connector sleeve around said tubing string;

a slot engaging lug projecting from said connector sleeve into said slot means;

a first slip engaging ring encircling said upper set of slips and cooperating with said upper slip retainer element to retain said upper set of slips in fixed axial relation to said connector sleeve and around said tubing; and

a second slip engaging ring encircling said lower set of slips and cooperating with said lower slip retainer element to retain said lower set of slips in fixed axial relation to said connector sleeve and around said tubing.

11. A well tool as defined in claim 10 wherein each of said packing sleeve assemblies comprises:

12. A well tool as defined in claim 11 wherein each of said resilient packing sleeves has embedded therein, a helical, metallic spring element helically surrounding said tubing string.

13. A well tool as defined in claim 12 and further characterized as including a pair of compression collars secured around the tubing string on the opposite sides of the upper and lower packing sleeve assemblies from the slip and drag block assembly and limiting axial movement of the packing sleeve assemblies on the tubing string.

14. A well tool comprising:

a section of tubing adapted for connection at its opposite ends to additional sections of tubing;

a rigid compression collar secured to said tubing section;

a packing sleeve assembly adjacent said compression collar and surrounding said tubing section, said packing Isleeve assembly including:

a frusto-conical, rigid, slip expander element slidably surrounding said tubing section; and

a body of resilient material secured between said slip expander element and said compression collar and slidably surrounding said tubing section; and

a set of slips circumferentially spaced from each other around said tubing section and mounted on said tubing section for axial movement toward and away from said slip expander element; and

a drag block movably mounted on each of said slips and manually detachable therefrom.

1S. A well tool as defined in claim 14 and further characterized to include a resilient, helical metallic spring element embedded in said body of resilient material and surrounding said tubing section.

16. In a well tool of the type having an expandable resilient packing sleeve thereon, and a slip-type anchoring device for simultaneously expanding the packing sleeve and anchoring a tubing string carrying the tool at a desired location in a Well casing, the improvement cornprising:

a hollow tubular member having said packing sleeve mounted thereon;

a plurality of slips movably mounted on said tubular member and each including:

an elongated shank portion;

a head portion secured to one end of said shank portion and having wickers thereon adapted to bitingly engage a well casing; and

a pair of spaced, L-shaped drag block retaining toes secured to said shank portion;

a drag block mova'bly ymounted on each of said slips and each having end portions extending between the L-shaped retaining toes and the shank portion of the respective slip upon which it is mounted; and

spring means positioned between each of said drag blocks and the respective slip upon which it is mounted for resiliently biasing the drag block away from the slip to move said end portions of the respective drag block into contact with the retaining toes of the respective slip.

17. The improvement in a well tool defined in claim 16 wherein said end portions of each of said drag blocks are characterized in having a convexly curved surface contacting said retaining toes; and

wherein the retaining toes of each slip have concavely curved surfaces adapted to mate with and receive the convexly curved surfaces of the end portions of the respective drag block in contact therewith whereby each of said drag blocks is restrained against movement in a direction which is transverse with respect to the elongated shank portion of the slip upon which it is mounted.

18. A combination slip and drag block for use in well tubing anchoring tools comprising:

a slip including:

an elongated shank portion;

a head portion secured to one end of said shank portion and having teeth along one side thereof for engaging a well casing;

a first L-shaped drag block retaining toe spaced from said head portion and having one leg of said first L-shaped retaining toe secured to said shank portion and extending substantially normal to said shank portion, and having a second leg of said first L-shaped retaining toe extending away from said head portion;

a second L-shaped drag block retaining toe spaced along said shank portion from said first L- shaped drag block retaining toe and having one leg secured to said shank portion and extending substantially normal thereto, and having a second leg extending toward said first L-shaped drag block retaining toe;

a slip retainer lip secured to said second L-shaped drag block retaining toe and extending substantially parallel to said shank portion and away from said first L-shaped drag block retaining toe;

a substantially trapezoidally shaped drag block extending substantially parallel to said shank portion, said drag block having a pair of end portions extending between the second legs of said first and second L- shaped drag block retaining toes and said shank portion; and

spring means extending between said shank portion and one side of said drag block for resiliently biasing said drag block away from said shank portion and the end portions of said drag block into contact with the second legs of said first and second L-shaped drag block retaining toes.

19. A well tool as defined in claim 14 wherein said section of tubing is formed in upper and lower portions threadedly interconnected, said compression collar and packing sleeve assembly being mounted on said lower portion, and said slips being mounted on said upper portion, lwhereby said upper portion and slips may be removed from a well in which the tool is positioned by unthreading said upper and lower portions in the event said packing sleeve assembly becomes stuck in the well.

20. A well tool as defined in claim 19 wherein said slips are mounted on a sleeve slidably disposed on said upper portion, and characterized further to include:

a pulling ring rigidly secured on said upper portion between said sleeve and packer sleeve assembly in a position to engage said sleeve and retract the slips from the slip expander upon a. partial unthreading of said upper and lower portions.

References Cited UNITED STATES PATENTS 3,282,343 11/1966 Tausch 166-138 3,412,790 11/1968 Brown 166-138 3,456,723 7/1969 Current et al. 166-134 JAMES A. LEPPINK, Primary Examiner U.S. C1. X.R. l66-l38, 191