US3366391A - Casing interliner - Google Patents

Description

Jan. 30, 1968 G. 1 GORE CASING INTERLINER 5 Sheets-Sheet vl Filed Aug. 2'7, 1965 INVENTOR. BYGeorge L. Gore ATTORNEYS Fig. l

Jan. 30, 1968 G GORE; 3,366,391

CASING INTERLINER Filed Aug. 27, 1965 5 Sheets-Sheet 2 l .f Fig. 2

INVENTOR.

George L. Gore ATTORNEYS Jan. 30', 1968 G. L.. GORE CASING INTERLINER 3 Sheets-Sheet 3 Filed Aug. 27, 1965 R. e /M m m MVG Ja# N /M/ e A m. M G y Y B A O v 9 ,h y m e 7 l, A g e .n A w m ATTORNEYS United States Patent O 3,366,391 CASING INTERLINER George L. Gore, 1759 Hudson St., Denver, Colo. 80220 Filed Aug. 27, 1965, Ser. No. 483,250 13 Claims. (Cl. 277-58) ABSTRACT OF THE DISCLOSURE An interliner for wells, for temporarily or permanently sealing off perforations or openings in a well casing formed as a sectional member, including resilient, stretchable, tubular sections, which are'combined with a rigid tubular section.

This invention relates to interliners for wells, for temporarily or permanently sealing off perforations or openings in a well casing or sealing off stratum in a well shaft. The invention relates more specifically to improvements in resilient casing interliners of the type which is disclosed in my Patent No. 3,067,819, issued Dec. 11, 1962. Hence, the present invention will be referred to as improved casing interliners and sometimes will be referred to as an interlinen The casing interliner disclosed in my prior patent is a tubular, resilient member having an external diameter greater than the inside diameter of the well casing it is to be fitted into, and the interliner is installed by being stretched to reduce its diameter before it is lowered into a well. It is then released to permit it to expand in diameter to tightly grip the wall of the casing. This permits the interliner to effectively seal off casing perforations or the like and permit a ow through the well, as from a lower level to an upper level and through the interiner, but preventing lHow through the openings sealed off by the interliner.

The present invention resides in improvements and modifications of this basic structure to permit the apparatus to be used in a more versatile manner. The apparatus disclosed in the Patent No. 3,067,819, is especially adapted to seal off standard perforations commonly made in a well casing at a producing zone, or to seal off a porous zone in certain -uncased well shafts where the formations are firm and the well hole is comparatively round, smooth and regular. However, the interliner cannot effectively seal off large openings or ruptures in a casing, nor can it bridge irregularities, pockets or caverns in an uncased well shaft which may be formed by the loss of material from a soft stratum through which the well shaft extends. Also, the resilient interliner cannot effectively seal off a high pressure, as from water or gas, and prevent flow from the stratum, through casing perforations, and into the well. This is the reverse of the usual situation, but such sometimes occurs at a higher level in the well, interfering with the production from a lower level.

To overcome such above mentioned limitations, the improved casing interliner, herein disclosed, is formed as a sectional member, including resilient, stretchable, tubular sections, which are combined with a rigid, tubular section. Also, an improved and simplified setting tool was developed for use with these liners, all as will be hereinafter set forth.

It follows that an object of the present invention is to provide a novel and improved casing interliner for sealing off a selected level or zone in a Well and especially for sealing off and spanning large openings and ruptures in casing and pockets and caverns in the well shaft to permit uninterrupted communication with lower levels or 3,366,391 Patented Jan. 30, 1968 ICC zones in the well, as for production .from and treatment of these lower levels.

Another object of the invention is to provide a novel and improved casing interliner for regaining the continuity of a well shaft, as where the casing has been ruptured or cut away or where a pocket or cavern has been formed in an uncased well shaft.

Another object of the invention is to provide a novel and improved casing interliner for sealing off selected levels or strata of a well in a precise, quick and reliable manner, which is characterized by being easily altered for use in many varied applications.

A further object of the invention is to provide a novel and improved casing interliner which is also adapted to seal off a level or zone in a well shaft against pressure from the zone tending to force oil, gas or water into the well, and also against pressure in the well tending to cause tiow from the well and into the zone, to thereby permit a lower level in the well shaft t0 be worked, treated or to produce without interference by liow into or from the higher zone.

Another object of the invention is to provide a novel and improved interliner construction which is especially adapted to grip the wall of a casing or well shaft to maintain itself in position and to support other instrumentalities associated therewith.

Another object of the invention is to provide an improved and simplified tool for stretching resilient interliners, placing them in a well shaft and releasing them at selected poistions.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain constructions, combinations and arrangements of parts and elements, as hereinafter described, defined in the appended claims and illustrated in preferred embodiments in the accompanying drawings, in which:

FIGURE 1 is a sectional elevation view of a reach of a cased well having a wide cutaway section in the casing and a pocket in the formation at the cutaway, as in a production zone, with the improved casing interliner being set in the casing to block off the cutaway section from the passageway through the casing.

FIGURE 2 is a sectional elevation view of the casing and interliner as taken from the indicated line 2 2 at FIG. 1, but on an enlarged scale and with reaches of unvarying section being broken away to condense the view and conserve space.

FIGURE 3 is a fragmentary, sectional detail of a portion of the interliner per se, as taken from the indicated line 3-3 at FIG. 2, but on an enlarged scale.

FIGURE 4 is a fragmentary detail, partly in section, of a portion of the interliner per se, as taken substantially from the indicated line 4 4 at FIG. 2, but on an enlarged scale.

FIGURE 5 is a fragmentary detail substantially the same as the showing at FIG. 4, but on an enlarged scale and illustrating, in a somewhat diagrammatic manner, the yielding of the resilient components of the interliner when they are pulled and reduced in diameter to permit it to be inserted into or removed from a well casing.

FIGURE 6 is a portion of the showing at FIG. 4 on an enlarged scale, including also a sectional view of a fragment of casing to illustrate, in a somewhat diagrammatic manner, the yielding of the resilient components as the interliner seals itself against the casing and onto its connecting ring, as when fluid in the casing is under great pressure.

FIGURE 7 is an elevational view of an arrangement, similar to that of FIG. 2, but illustrating the interliner as being set in an uncased well shaft and with a rigid portion spanning a cavern within the well shaft to block olf the cavern from the shaftV passageway through the interliner.

FIGURE 8 is an elevational view, similar to FIG. 7, but illustrating a modied construction of the interliner as being set at the bottom of a cased section of a well shaft to bridge a pocket formed at the discontinuity between the casing and the uncased section of the shaft therebelow.

FIGURE 9 is a fragmentary, sectionalV detail, as taken from the indicated line 9-9 at FIG. 8, but on a greatly enlarged scale.

FIGURE 10 is an elevational view, similar to FIG. 7, but illustrating another modified construction of the interliner which is arranged to seal off a perforated section of the casing from ow in either direction, as from a strata through the perforated section and into the casing or from the casing, through the perforations and into the strata.

FIGURE 11 is a fragmentary, sectional detail, as taken from the indicated line 11-11 of FIG. l0, but on an enlarged scale.

FIGURE 12 is a fragmentary, sectional detail, as taken from the indicated line 12--12 at FIG. 10, but on an enlarged scale.

FIGURES 13, 14 and 15 are fragmentary, sectional details, similar to a portion of the showing at FIG. 4,

but illustrating alternate arrangements of the components shown therein.

FIGURE 16 is a longitudinal, sectional elevation of the apparatus shown at FIGS. 1 and 2, but illustrating the interliner as being mounted upon a setting tool, stretched by the tool and placed in a well casing and illustrating in broken lines the manner in which the resilient components of the liner contract to enlarge in diameter to grip the casing wall when the setting tool is released, and also illustrating, diagrammatically, a simple form of a clamp for holding the apparatus in position prior to lowering it into a well shaft.

FIGURES 17, 18, 19 and 2() are fragmentary sectional details of the setting tool per se, as taken substantially from the respective indicated lines 17-17, 18-18, 19-19 and 20-20 at FIG. 16.

Referring more particularly to the drawing, FIG. 1, exemplary of one use of the present invention, illustrates an improved interliner L set in a portion of a well shaft S finished by a casing C having a cutaway section K in the casing at a production zone Z. This cutaway section exposes a circular pocket in the formation about the Well shaft and is effective to enhance ow of oil into the well from the production zone. Such a cutaway portion K in the casing, and the pocket in the production zone, may be formed in various ways, as by the elfect of an explosive charge, or by the action of a high-velocity abrasive jet or by a casing failure. Also, the cutaway and pocket may be of a regular, somewhat symmetrical form about the shaft, as illustrated, or it may be irregular and even at only one side of the casing.

In maintaining and servicing the Well, especially at levels below the illustrated production zone Z, it may be desirable and even necessary to close off the opening K, especially when fluid is being pumped into the well under pressure, as to improve the production capacity of a lower level in the well. In many instances where such servicing operations are required at a lower level, openings in the casing at an upper zone, such as zone Z, will be perforations, that is, comparatively small holes and when this situation exists, the casing interliner disclosed in my Patent No. 3,067,819 `will easily and effectively close olf the upper zone. However, where a substantially wide section of the casing is cut away, such as the illustrated portion K, to expose a pocket in the formation back of the cut, the resilient casing interliner disclosed in the Patent No. 3,067, 819 can be easily ruptured when fluid under pressure is pumped into the well casing.

The improved interliner L overcomes the difficulty of blocking off a cutaway portion K in the casing or any similar large pocket or cavern in a well shaft by using a rigid member at the cutaway portion. It is formed as a sectional member having resilient sections at each end for gripping the wall of a well shaft and a rigid central section to span a cutaway or cavern in the shaft. In its normal vertical position, the interliner L may be described as comprising an upper gripping section 25, an intermediate spanning section 26 and a lower gripping section 27. The gripping sections 25 and 27 are preferably substantially identical in form except that the lower section will be reversed in position with respect to the upper section, the lower end of the lower section being the same as the upper end of the upper section. Accordingly, the components described as being on the section 25 Will also be on the section 27.

Each gripping section, 25 and 27, is a thick-walled, resilient tube of rubber-like material which is resistant to oil, such as neoprene. Each gripping section is reinforced with one or more layers of fabric 28 arranged in a cylindrical pattern Within the walls of the tube, the weave of the fabric being on a bias with respect to the longitudinal axis of the tube, as illustrated at FIG. 5. This permits the fabric 28 to yield when the tube is stretched, as will be hereinafter further described.

Each gripping section tube, 25 and 27, is normally larger in diameter than the inside diameter of the casing or well shaft into which it is to be inserted, In use, these section tubes, at each end of the interliner, are stretched to reduce their diameter to less than the inside diameter of the casing. The interliner is then inserted into the well and lowered into position. Then the sections are released to shorten and, at the same time, expand and effectively grip the wall of the well shaft. Each gripping section tube is comparatively moderately thick to provide for a substantial compressive action when it is expanded to grip the wall of the well shaft and to provide a moderately rigid unit when being handled outside the well. As an example, a casing having an inside diameter of 6.36 inches will use gripping sections having an outside diameter of approximately 6.6 inches. The wall of such a tubular gripping section will be approximately %inch thick. However, when such a section is stretched, the outside diameter of the tube may be reduced to a diameter as small as 5% inches, to easily lit into the 6.36 inside diameter casing or in casing having even a smaller inside diameter.

A tool holding head 30 is formed at the upper and lower ends of the interliner L, that is, atthe outward end of each gripping section, 25 and 27. It is contemplated that the gripping sections of an interliner L will be stretched for insertion into a casing by a stretching tool T which is adapted to be extended into the interliner and Contact the opposing heads 30, as in the manner illustrated `at FIG. 16. To form the heads 30, the end of each thick-walled gripping tube is reduced in diameter at this head to provide a neck 31 adapted to easily fit Within any casing or well shaft in which the interliner will be used. A short, tubular, rigid sleeve 32, having an internal diameter the same as the normal internal diameter of the gripping section, is molded into each neck 31, the sleeve having itsY outer surface grooved as at 33 to enhance the grip between it and the rubber body of the neck 31. The

Voutward end of the sleeve 32 extends beyond the end of the neck 31 and is enlarged in diameter to form a -holding ring 34 which is internally threaded as at 35. This holding ring 34 is thus adapted to receive a short anchor ring 36 which has an externally threaded portion 35 to permit it to be turned into the holding ring, with the inward end within the sleeve 32 forming a tool-holding shoulder 37. The outward end of the anchor ring is enlarged to provide a shoulder 38 which is adapted to abut against the end of the holding ring for a tight fit when the two members are connected together.

Whenever the stretching tool T is inserted into the interliner with the tool-holding shoulders 37 at opposite ends of the interliner being gripped, the gripping sections, and 27 may be stretched and at the same time reduced in diameter, This reduction of diameter is enhanced by the biased reinforcing fabric 28. The action of the fabric is especially important at the neck 31, for the effect of pulling and reducing the tube diameter is to tightly grip the sleeve 32 to prevent any tendency for the ends of the gripping section to slip o the sleeves. In use, it was found that such was adequate to retain a sleeve in the neck 31 even under a substantial pull. However, should further reinforcement be desired, the sleeve may be secured in place in the neck 31 of the gripping section, as by rivets extending through the neck and sleeve.

A connecting head is formed at the inward end of each gripping section tube, 25 and 27, to connect with the rigid spanning section 26. Each vthick-walled gripping tube is reduced in diameter at its inner end to provide a short neck 41, similar to the opposite neck 31. The neck 41 is adapted to easily fit within any casing or well shaft wherein the interliner will be used, even with a sleeve ttted about it, as will be described. This connecting head 40 may be formed in different ways, as will be hereinafter further described. However, in the arrangement illustrated at FIG. 4, the head 40 includes a tubular internal sleeve 42 which is adapted to be slidably inserted into neck 41 of the gripping tube, 25 or 27, with a snug, moderately tight t. The length of the sleeve is such that one portion will fit in the neck 41 and another portion will project a short distance beyond the end of the neck to form a threaded stub 43.

To complete the connector head, a short tubular external sleeve 44 is adapted to embrace the neck 41 with a snug, moderately tight fit. The lower end of the sleeve is formed with an inturned flange 45 which is adapted to grip the stub portion of the internal sleeve 42 with a moderately tight fit and to be abuttcd against the end of the neck 41. The fiange 45 is secured to the sleeve 42 by a weld 46 to provide a fluid-tight t. By so welding or otherwise joining the internal sleeve and external sleeve, an annular socket is formed which receives the neck 41 and restrains the neck when it is being pulled or when the interliner is under pressure. Once the neck 41 of the gripping tube, 25 or 27, is inserted into this socket, one or more rings of holes 47 may be drilled through the internal and external rings 42 and 44, and tapped to receive holding screws 48.

In contrast to the requirements of the outward toolholding heads 3i) which are adapted to resist only tension, the connecting head 40 must be adapted to withstand both tension, as when the gripping sections are being stretched, and internal pressure, as when the interliner L is in place and fluid is being pumped into the well through the casing. The tension effect resulting from stretching the gripping section is illustrated at FIG. 5. The pulling action causes the gripping tube to be stretched reduced in diameter, with the reinforcing fabric 28 in the neck 41 effecting a very tight gripping of the neck 41 about the sleeve 42. This gripping will normally automatically hold the neck 41 on the sleeve 42; however, any tendency for the gripping section to slip off the sleeve will be inhibited by the holding screws 48.

The effect of a fluid within the casing under pressure is to push the gripping tubes, 26 and 28, tightly against the casing wall and to push the neck 41 of each tube against its external sleeve 44. Where the pressure is great, the neck 41 may actually separate from the internal sleeve, permitting fluid to enter a portion of tne socket, as in the manner illustrated at FIG. 6. Although the separation in that figure is somewhat exaggerated, it is apparent that a sealing-off effect is obtained by the neck 41 pressing against the sleeve 44.

The spanning section 26 is preferably a rigid tube having an external diameter substantially the same as the threaded stub end 43 of the internal sleeve 42 so that each end of the spanning section can be threaded as at 50 and connected to the stub ends 43 of the connecting heads 40 of the upper and lower gripping sections, as by couplings 51. It is to be noted that the arrangement above described provides for a versatile apparatus, for the spanning section 26 may be of any desired length, and it may be used not only to span a cutaway section K in a cased well where the entire unit may be comparatively short, but it may be of a substantial length to be used in an uncased well shaft as to span a large pocket or cavern which might form after drilling is completed and in a section where permanent casin-g is not desired, such as the arrangement shown at FIG. 7.

It was found that certain requirements for liners were necessary when they were used in an uncased well, including the requirement that they be of a normal diameter greater than the diameter of the well shaft. It was found that the formation whereagainst the upper and lower gripping sections were to be set had to be comparatively hard and cleanly drilled, preferably with reamer attachments on the drilling apparatus. However, such conditions are usually obtained in a well shaft, and a loose formation which tends to spall to form undesirable pockets is usually bounded by comparatively hard formations which can be cleanly drilled.

Various modifications to the arrangement set forth at FIGS. 1 through 7 are possible, as by using a lower gripping section 27 with a modified spanning section 26 having a casing-sealing arrangement attached directly to it. The interliner L' illustrated at FIG. 8 combines a lower gripping section 27, having a tool head 30 at its lower end and a connecting head 40 at its upper end, as heretofore described .The spanning section 26 is attached to the head 40 by a coupling 51 and includes a coupling 51 at its upper end.

A sealing head 55, formed as a short, tubular stub having threads 50' at one end, is connected to the upper collar 51 `of the spanning section 26. An upwardly directed seal cup 56 girdles this head 55 and is held in position in a socket formed by an angle ring 57 about the stub, the angle ring being secured to the stub in any suitable manner, preferably by a weld 58. This seal cup 56 is formed with an upwardly directed outared lip which is adapted to engage the wall of a casing C when the interliner L is inserted into a well shaft. This prevents uid ow from within the well past the upper end of the spanning section and into the space between the well shaft and the tubular spanning section.

The unit is completed by an annular, tool-engaging ring 59 Within the end 55, which is adapted to permit a stretching tool to be inserted into the interliner L to grip the end of the unit for stretching the interliner to insert it in a shaft and to permit a retriever to grip the top of the unit to pull it out of a well.

This particular arrangement may be used in a cased well shaft the same as the interliner L, hereinbefore described, to seal off perforations on a cutaway section in casing, with the lower gripping section functioning to hold the apparatus in place. A further advantage of this arrangement may be obtained where the lower end of the interliner L', the gripping section 27, is extended below the end of the casing and to be held by uncased formation, Abut with the seal cup 56 engaging the walls of the casing thereabove, such an arrangement blocking off a discontinuity or pocket which sometimes forms in the uncased shaft below the casing, as illustrated at FIG. 8.

The modified interliner L", illustrated at FIGS. 10, 11 and 12, provides for a sealing arrangement in a casin-g C where the pressure is directed inwardly from the formation about the casing through an opening such as perforations P in the casing. Often a casing is perforated at several levels after a well is drilled to obtain production from as many zones as possible. However, an upper zone sometimes develops excess gas pressure or commences to flow water under pressure in a manner which adversely affects production from lower zones in the well, and it is essential that the flow of gas or water at the upper Zone be cut ortf. This is conventionally done lby scab liners, and the unit illustrated at FIG. l includes features of a conventional scab liner combined with a gripping section adapted to facilitate holding the liner L in place within the well.

The lower gripping section 27, illustrated at FIG. 10, is modied from the construction heretofore described only by making the short sleeve 42 of the connecting head 40 integral with an extended tube which functions as a modified spanning tube 26, and it is to be noted that the arrangement shows at FIG. 10 could be otherwise modified by using the aforedescribed gripping section 27, in combination with a separate modified spanning tube section 26" by use of a coupling 51.

The modified spanning tube section 26" is provided with a pair of inwardly directed, opposing seal cups 56a spaced at opposite ends of the section tube 26 and an outwardly directed seal cup .56h at the upper end of the tube 26".

These seal cups girdle the section tube and are held in place by angle rings 57 secured to the tube by welds 58. It is to be noted that the angle rings 57 for the upper seal cups 56a and 565 may be placed closely together and held by a common weld, as illustrated at FIG. 11, and the lower seal cup 56a and the external sleeve 44 of the connecting head may be likewise spaced closely together, as illustrated at FIG. 12. The unit is completed by an internal tool-engaging ring 59 set within the top end of the section 26".

The inwardly directed seal cups 56a are spaced apart on the section tube 26" a distance suicient to span the reach of a selected series of perforations P of a casing which are to be blocked off from the well and when the interliner L is set in position in the casing. With the perforations P between the opposing seal cups 56a, the pressure of flow from the formation through the perforations and into the casing will cause these seal cups to tightly grip the wall of the casing and shut ofiC flow into the well. Flow 'from the well and into the formation is also effectively shut ofi `by the upwardly directed seal cup 56h cooperating with the lower gripping section 27, so that the interliner L is an effective and efficient double acting unit.

' One important feature of the present invention resides in the construction of the connecting head 40 which is characterized by an inner sleeve 42 and an external sleeve 44 having the inturned ange which connects with the sleeve 42 to form an annular socket, wherein the neck 41 of a gripping section is set. FIGS. 13, 14 and 15 illustrate alternate constructions of the arrangements shown at FIG. 4. FIG. 13 illustrates a head 40a which uses an inner sleeve 42a which is externally threaded as at 60 and is of a size which can be turned into the neck 41 to grip the internal wall of the neck by the threads 6G biting into the rubber wall. Lubricants can be used to facilitate this connection. An external sleeve 44a is internally threaded as at 61 to grip the external wall of the neck. This external sleeve includes an inturned flange 45a internally threaded at 60' to mesh with threads of sleeve 42a, the threads 64) and 61 being lof the same pitch and direction so that assembly of the head may be simplified, by lirst turning the internal vsleeve 42a onto the neck 41 and tlhen turning the external sleeve 44a onto the neck and internal sleeve simultaneously. With the threads so gripping the neck, holding screws 48 will ordinarily be unnecessary with this construction.

The unit illustrated at FIG. 14 provides for an internal sleeve 42b which is molded'into the neck portion 41h in theA same manner asthe sleeve 32 is molded in the neck 31 of the toolV head 30. The internal sleeve 42h is also similar in form to the sleeve 32, having a ribbed outer surface to more effectively grip the neck, andan enlarged holding ring 62, similar to the ring 34 of sleeve 32, modified only by having external threads as at 63 and being of a diameter slightly less than that of the external .diameter of the neck 41b. This permits an external sleeve 44b, adapted to lit snugly over the neck 4117, to be provided with a stub portion 64 having internal threads 63' which may engage with threads 63 when the sleeve 44b is fitted upon the neck 41b. The threads 63 are extended in the stub 64 to form female threads to form a coupler for holding a spanning section tube 26, thus eliminating the coupling 51.

The unit illustrated at FIG. 15 provides for an internal sleeve 42C which is molded into the neck 41C, the same as the sleeve 32, heretofore described. This ,sleeve is formed with a holding ring 65 which abuts against the end of the neck section 41 and includes a stub portion 66 having internal threads 67 and serving as a coupling for direct vconnection to a spanning section 26. A tubular external sleeve may be fastened over this neck section 41 and connected to the stub portion 66 in any suitable manner. As an alternate to the external sleeve construction, a Y

wire 66 or like strong cord may be wrapped about this neck 41C to hold it tightly against the sleeve 42e. It is to be noted that in this arrangement, the wire must be wrapped tightly and actually pre-stressed, and the tightness with which the wire must be wrapped is dependent upon the maximum pressure within the casing which the interliner will be subjected to. A high pressure sul'licient to move the interliner away from the internal sleeve 42e, as in the manner illustrated at FIG. 6, could cause leakage since the wire cannot confine the end of the gripping tube in the manner of a socket-like construction, such as that heretofore described.

An improved stretching tool T, especially adapted to be inserted into and used with the interliner constructions L, L and L" is illustrated at FIGS. 16 to 20. The upper portion of the stretcher tool T is a tubular body 70, and the lower portion of the tool is rod 71 which telescopically eX- tends into t'he body 70. The upper end of the body 70 and the lower end of the rod 71 carry laterally extendible linger means adapted to engage with anchor rings 36 Within the tool head 30 of a gripping section or with a tool engaging ring 59 of a seal head or a modified spanning section 26". The inner end of the rod 71 which telescopically extends into the body includes a friction lock means which permits the tool to be mounted within an interliner and to be exended as the interliner is stretched and to thereupon lock in the extended position to hold the stretched interliner until it is lowered into a well shaft, as in the manner illustrated at FIG. 16. Once positioned in the shaft, the linger means of the body may be collapsed to release the interliner from the stretching tool T, all as will be further described.

The body is formed as a plurality of tubular sections which are suitably threaded together as a single extended member. The body is topped by a cable connector cap 72 which connects with a wire cable 73 `for supporting and holding the assembly. This cap connects to an upper section 74 which carries the fingers and linger holding and releasing means. Next, one or more intermediate spacer sections 75 depends from the top section to establish a proper length of the body, and the lower end of the spacer section is closed by a rod guide 76.

The upper section 74 is a comparatively thick-walled tubular member having circumferential array of, and preferably three, longitudinal slots 77,' wherein radially extended rockers 78 are mounted, as on pivots 79, inthe Wall of the section. Each rocker 78 is a balanced member having an outward gripping linger 80 and an inward holding Y linger 81. Each gripping finger outstands from the wall of the section as to grip the abutment shoulder 37 of an anchor ring when the fingers are in a locking position.-

wardly to the center of the section to abut against the Y lower end of a lock piston 82 when in a locking position. The lock piston extends upwardly to a chamber 83 at the top of the upper section 74 and abuts against a release tube 84 which, in turn, extends to the top of the chamber to abut against an adjusting plug 85 set in a threaded socket S6 at the top of the chamber. It is contemplated that the release tube 84 shall be of ceramic or other frangible material, and it may be shattered by an explosive cap 86 within it, the cap including lead wires 87 which extend through a Ihole in the plug 85 and into the head 72 for connection to a conductor cable inside the Wire line 73, and thence to the surface of a well shaft, wherein the apparatus is set. By energizing the wires with an electrical charge, an operator may detonate the cap whenever he desires. When the tube 84 is shattered, the piston S2 is released to permit the holding lingers to swing upwardly and the gripping fingers to swing downwardly and into the slots 77 to release the stretching tool T from an interliner.

The spacer sections 75 are tubular members threaded t0 the upper section and to each other to obtain a length corresponding to the length of an interliner. These sections are preferably formed with a smooth inner wall to facilitate the movement and gripping of the gripping means of the rod 71. The lower rod guide 76 vcompleting the body is a simple cap member which is threaded onto the end of the bottom spacer section and includes a central passageway 88 adapted to hold the guide rod 71 at a centered position with respect to the axis of the body 70 and prevent it from falling out of the body.

The guide rod 71 is of a length sufficient to be extended from the body a distance greater than the maximum increase in length of the gripping sections and 27 when the interliner is stretched, to permit it to be mounted in an unstretched interliner when retracted into the body and then extend as the interliner is stretched.

An enlarged cylindrical head 90 is threaded onto the lower end of the rod and includes the bail 91 at its bottom for connection with a cable or ancor. This head is provided with longitudinal slots 92 which carry tingers 93 mounted -on pivots 94 within the slots. T e iingers are adapted to swing outwardly from the head to grip an anchor ring 36. To facilitate such outward movement, a spring 95 is mounted behind each finger, `and to limit the movement, a stop 96 is formed on each iinger to contact the head to limit its outward movement.

The gripping means 4of the rod 71 is a directional slip and wedge arrangement at the upper end Vof the rod Within the spacer sections 75 of the body and -is `adapted to permit the rod to move outwardly to lengthen the tool, but to lock against movement of the rod inwardly. The wedge arrangement includes a conical abutment ring 97 near, but not at, the upper end of the rod with the incl-ined conical surface facing the upper end. A slide ring 9S is mounted on this end portion of the rod adjacent to the top and held thereon by a cap nut 99 at the end of the rod.

The ring 93 carries a circular array of resilient fingers 109 which lie in spaced parallelism with the axis of the rod and are directed towards the conical abutment ring 97. Each iinger carries a wedge 101 having its outer surface serrated or otherwise finished to effectively grip the inner wall of a spacer section tube 75 and its inner surface adapted to slide on the wedge cone 97. A spring 102 may be inserted between the cap nut 99 and the slide ring 98 to urge the wedges against the cone whenever extension of the rod from the body tends to pull the cone of ring 97 away from the Wedges.

In use of `this apparatus, the body is prepared by turning together sutiicient spacer sections 75 to give the tool the same length as the interliner in which it -is to be used, with the rod 71 being fully retracted into the body 70. The tool is then inserted into the yinterliner and the iingers on the body and rod are set against the top and bottom anchor rings of the interliners. Next, the top cap 72 and bail 91 are gripped by any suitable pulling apparatus and are pulled apart. This pulling stretches the interliner and extends the rod from the body. When a suitable stretch is obtained, the pulling apparatus is disconnected and the gripping means at the inner end of the rod locks the rod to the body to keep the interliner stretched. It is then lowered into a well shaft to a selected position, the explosive cap detonated to shatter the tube 84, withdraw the iingers and release the interliner from the tool. The tool is then withdrawn from the well shaft.

The rod 71 of this tool may be advantageously used to retrieve an interliner set in a well. The rod 71 is removed from the body and inverted, with the bail being attached to a cable. It is then lowered into the well shaft, into the top of the interliner. They then `open to grip the anchor ring. The interliner may then be pulled out of the hole.

It is to be noted that variations in use of the invention are possible without changing the basic arrangement of the apparatus. For example, the units illustrated at FIGS. 8 and 10 maybe inverted from the positions shown, with the spanning sections 26 or 26 being downward from the gripping section. As an example of the versatility of the invention, it was found desirable to invert the unit shown at FIG. l0 so the spanning section 22 extended downwardly as into a cavern to function as `a guide tube permitting pumping `of fluid into or out of the cavern at a selected level as at the base of the cavern. In this arrangement, the gripping section 27" functioned as heretofore described. The cup 56a, adjacent to the gripping section, was retained, but the cups 56a and 56b at the extended end of the spanning section were not used.

While I have now described my invention in considerable detail, it is obvious that others skilled in the art can build and devise alternate and equivalent constructions which are nevertheless `within the spirit and scope of my invention. Hence, I desire that my protection be limited not by the constructions illustrated and described, but only by the proper scope of the appended claims.

What is claimed is:

1. A tubular casing interliner comprising a gripping section tube `formed as a tubular length of resilient material adapted to be reduced in diameter when under tension, a tool head at one end of the gripping section tube for engagement by a tension producing tool adapted to be inserted within the interliner, a spanning section formed .as a tubular length of rigid material at the other end of the gripping section tube to extend therefrom, and a tool holding shoulder ywithin the spanning section adapted to be engaged by `said tension producing tool.

2. In the casing interliner defined in claim 1, .including a second length of resilient material connected to the extended end of the spanning section and wherein `said tool holding shoulder is located at the further extended end of the said second length of resilient material.

3. In the casing interliner defined in claim 1, wherein 'said spanning section includes casing-wall-sealing means adapted to seal off an -annular space between a casing wall and the said spanning section from the passageway extending through the interliner.

4. lIn the casing interliner defined in claim 1, wherein said spanning section extends into the end of the gripping section.

5. In the casing interliner defined in claim 1, wherein said spanning section extends into the end of the gripping section and an external sleeve about the said end of the gripping section secured to the spanning section tube.

6. In a casing interliner including a gripping section formed as a tubular length yof resilient material adapted to be reduced in diameter when under tension and a spanning section formed as a tubular length of rigid material extending from one end of the gripping section, a connecting means at the juncture of the sections, securing them together and being adapted to `withstand forces tending to pull them apart and internal fluid pressure forces within the interliner as lwhen it is set within a casing, and comprising, a neck at the end of the gripping section formed as a short cylindrical tube and concentric cylindrical inner and outer sleeves at the end of the spanning section adapted to receive and hold the gripping-section neck with a snug t, whereby the neck is adapted to grip the inner sleeve when it is being pulled and reduced in diameter, and is adapted to expand against the outer sleeve when the interliner is under pressure.

7. In `the interliner defined in claim 6, wherein the connecting means is formed as a head mounted upon the gripping section and includes coupling means for connection with the spanning section.

8. In the interliner dened in claim 6, wherein said inner sleeve is molde-d into the grippingsection neck as an integral part thereof and the lbuter sleeve is adapted to telescope over the `outer surface of the neck when mounted upon the inner sleeve and to be secured to the inner sleeve.

9. 'In the interliner defined in claim 6, wherein the outer sleeve is formed as a wrapping about the neck.

10. In the interliner defined in claim 6, wherein the inner sleeve consists of the end of the spanning section tube.

11. A casing interliner adapted to be placed in a well shaft and comprising, a gripping section formed as a tubular length of resilient material having a diameter greater than the well shaft diameter and adapted to be reduced in diameter less than the well shaft diameter when under tension, an anchor-tool head at one end of the tube adapted to be engaged by a tension producing apparatus extended into the interliner, and a spanning section formed as a Itubular length 4of rigid material having a diameter less than the lwell shaft ,diameter at the 4other end of the gripping section, means associated with the `spanning section adapted to permit gripping by a tension producing apparatus and means associa-ted with the spanning section to effect a sealing action about the well shaft when the interliner is placed in a well shaft.

12. In the organization set forth in claim 11, wherein said sealing means comprise a cup seal.

13. In the organization set forth in claim 11, wherein the sealing means comprise a pair of cup seals spaced apart -on the spanning section in opposition tol each other, whereby to resist pressure between the lspanning ysection and casing when the section is set in casing.

References Cited UNITED STATES PATENTS 2,026,883 1/1936 Gillespie 277-5 2,711,220 6/1955 Simmons 277-58 X 3,067,819 12/1962 Gore 16S-48 3,246,393 4/1966 Worth 277-9 X SAMUEL ROTHBERG, Primary Examiner.

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