US3067819A - Casing interliner - Google Patents

Description

G. l.. GORE 3,067,819

CASING INTERLINER 2 Sheets-Sheet 1 Dec. l1, 1962 Filed June 2, 1958 illl Fig. 3

INVENTOR. George L. Gore BY WHITEHEAD VOGL SILOWE ATTORNEYS PER ,jf

United States Patent C) Filed .lune 2, 1958, Ser. No. 739,417 16 Claims. (Cl. MiG-43) This invention relates to methods and apparatus for temporarily and permanently closing and sealing off openings in the wall of a pipe or casing, and more particularly to interliners for so temporarily or permanently sealing off openings in the wall of well casing. The invention has special utility in oil wells where it is often necessary to temporarily or permanently seal olf a ruptured or perforated section of the casing. As such, the invention will hereinafter be described as an interliner for an oil well casing, although it is to be understood that the invention is also suitable for use in other environments where like results are to be obtained.

In completing an oil well, the drilled shaft is cased with a pipe of substantially the same diameter of the shaft in order lto seal off the various strata through which the shaft passes, and especially the oil bearing strata from other permeable strata and to prevent inward collapse of the shaft. After the casing has been set and cemented to isolate selected strata, it is perforated at the levels of oil bearing strata or sands to permit the oil to ow into the casing so that -it may be subsequently pumped from the well. Since many wells extend through several oil and gas producing zones or sands which are at different levels, there may be several corresponding levels at which the casing is perforated. With `such an arrangement, the full potential of production from a well may be realized.

In a cased well having several perforated oil producing levels, itis natural to assume that the oil will flow from the different levels in different Iamounts and at different pressure and that problems of maintenance involving operating upon or treating of Ithe producing sands will not arise at the same time in the various levels. There are occasions when it is expedient and desirable to work with, treat or produce oil from yonly one level. For example, to more fully exploit the flow at one level it may be desirable to subject the sands at that level to chemical or 4other treatment and at the same time it is necessary to avoid simultaneously treating the sands of a different level.

Modern methods for treating an oil bearing strata include pumping treating fluid Vinto .the selected str-ata or sands under high pressure, and it is desirable to inject large amounts of the treating material into the strata as fast as possible. Naturally it is essential to prevent the treating material from entering the wr-ong level and this necessitates a closing olf of the perfo-rations in the casing at those levels which are not to be treated. Where the treating uid must pass Va. perforated section of the casing above the zone to be treated, this section must be closed olf. Even where two different production zones are to be treated, it is usually desirable to treat one zone at a time and the rst zone to be treated may be an upper or lower zone.

To temporarily seal off lthe perforations of one zone while operating with or upon lthe other zone, plugs and packers which close the entire casing are used where only an upper zone -is being treated. Where the situation is otherwise, and a lower zone is to be treated, attempts are made to close the perforations by rubber ball Sealers and the like in the treating fluid which plug the perfor-ations by the flow of treating fluid into the level to be cut off. This is not satisfactory, it is wasteful, uncertain and a certain amount of treating fluid is lost in order to accomplish the purpose.

It follows that there is areal and a definite need for improved apparatus for temporarily sealing off a perfo- ICC rated or ruptured section of a casing without obstructing the passageway through lthe casing. Interliners have been suggested for this purpose which use a length of pipe of smaller diameter than the casing. The practice is to set this pipe and attempt to seal the ends. Such units are not satisfactory since they cannot be eifectively end-sealed without substantially reducing the passage diameter through the casing.

With the foregoing, and other considerations in view, the present invention was conceived and developed to provide improved resilient-type interliner which may be set and secured in a casing at a selected location to seal of any perforations or rupture in that section of the wall of the casing. The primary object of the invention is thus to provide a novel and improved interliner for well casing which will effectively seal off any perforation or rupture in the wall of a casing.

Another object of the invention is to provide an imi proved resilient interliner for well casing which expansively grips the inner -wall of the casing at the point where it is to be set, to seal off perforations or ruptures in the well casing against both inward and outward pressure.

Yet another object of the invention is to provide, in combination with a resiliently-expandable wall-gripping interliner for well casing, improved means and apparatus for inserting, setting and subsequently removing the interliner from the casing.

Yet another object of the invention kis .to provide a novel and improved interliner for setting in a well casing at a selected location, which is tubular in form and will not impede the flow of liquids nor the movement of tools there past.

Yet other objects of the invention are to provide a novel and improved resiliently-expandable wall-gripping interliner for well casing which: may be temporarily or permanently set in position; is easy to use; reliable in operation; inexpensive and is rugged and durable.

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

FIGURE l is a longitudinal section of representative portions of a cased well shaft, where oil producing sands exist and where the casing is perforated with intermediate sections being broken away to conserve space and with the upper level of producing sand being sealed off by an interliner constructe-d in accordance with the invention.

FIGURE 2 is a longitudinal sectional elevation of the interliner before use in a casing and with setting apparatus positioned within the interliner preliminary to use.

FIGURE 3 is a longitudinal sectional elevation similar to FIG. 2, but illustrating the setting apparatus extending and reducing [the diameter of the interliner preliminary to insertion into the casing.

FIGURE 4 is a transverse section as taken substantially from the indicated line 4-4 at FIG. 2.

FIGURE 5 is a longitudinal sectional elevation of an interliner and setting tool similar to FIG. 3, but illustrating a modified construction of the setting tool.

FIGURE 6 is a longitudinal section of a modified construction of the interliner to illustrate another embodiment of the invention.

FIGURE 7 illustrates a longitudinal section of a representative portion of a cased well shaft, at an oil bearing stratra where the casing is perforated, and illustrating another modified form of interliner permanently set therein. l

FIGURE 8 is a longitudinal sectional elevation of the spargere 3 interliner shown at FIG. 7 mounted upon a setting tool with broken lines indicating the final position of the interliner after it is released from the tool.

FIGURE 9 is a fragmentary sectional view as taken on the indicated line 9 9 at FIG. 8.

Referring to the drawing and more particularly to FIG. 1 thereof, a typical oil well shaft extends through various impervious and pervious formations and may extend through one or more producing oil sand formations at different levels in the well shaft as at S and S'. The well shaft is walled by a casing which is lowered into the well when the shaft is completed and ,the oil sand formations S and S' at the different levels are separated physically by an impervious formation K which substantially seals the hole about the casing especially when the casing is cemented in place. Where the oil producing formations, such as S and S' are located, the casing is perforated by a regular array of punched holes or performations 16 so that the oil may How into the casing for pumping.

The casing 15 is a series of pipe lengths of constant diameter which are threaded together by couplings 17 and while there are several sizes available, casing is ordinarily a standardized product available only in selected external and internal diameters. This standardization of casing size permits the economical construction and use of interliners of standard size for selected sizes of casing as hereinafter set forth.

My invention is an interliner 20 which is formed as an expandable tubular section of resilient rubber-like material having oil resisting properties, such as neoprene.

A given interliner tube 20 is formed with Aa selected external diameter D for use with a given casing pipe 15 having an internal diameter d which is slightly less than the external diameter D of the interliner tube, as clearly indicated by the dimension arrows D and d at FIG. 2, the arrow d being between spaced lines 15 representing the internal diameter of the casing 15. Because of this, the tube 20 will be tightly embraced by the wall of the casing to seal off the perforations 16 as at the formation S. It is further contemplated that these sections of resilient tubing may be provided at any desired length, and they can be properly set by reference to the log of the well.

In order to insert this oversize tubular interliner 20 into the casing 15 itis necessary to stretch the interliner a substantial amount for such stretching willreduce the outside diameter of the interliner, and when reduced to a smaller diameter D which is less than -the internal diameter d of the casing, insertion is easily possible, as clearly t indicated `by the comparative dimensional arrows D and d at FIG. 3.

Once lowered into the casing to a selected depth, the stretched interliner may then be set by simply releasing the stretch to permit the interliner 20 to retract towards its original form and larger diameter D until the wall of the casing is tightly gripped. Removal of the interliner is possible by simply restretching the unit to reduce its diameter.

In order to stretch the interliner 20 it is necessary to grip each end of the interliner with an extender tool. End gripping means must be incorporated at each end of the interliner. In the embodiment illustrated at FIGS. 1 through 4, the interliner 20 is formed with a top anchor ring 21 and a bottom anchor ring 22. Each anchor ring is welded to and grips an end section 23 of the tubing between inner and outer concentric shells 24 and 25 extending axially from each anchor ring 21 and 22. The top anchor ring 21 includes an internal annular seat or shoulder 26 which faces downwardly toward the center ofthe interliner and the internal diameter of this shoulder 26 is substantially the same as the internal diameter of the body of the tubular interliner 20 when it is relaxed so that `any extender tool having a diameter 4 slightly less than the internal diameter of the interliner can move into the interliner past the shoulder 26.

The bottom anchor ring 22 includes an internal annular seat or shoulder 27 facing upwardly toward the center of the interliner 20. The internal diameter of this bottom shoulder 27 is less than the internal diameter of the top shoulder 26 and less than the inside diameter of the interliner 20 when it is relaxed so that any extender tool having a diameter only slightly less than the internal diameter of the interliner can be inserted into the top of the interliner and will contact and seat upon the bottom shoulder 27 as hereinafter described.

To complete the interliner unit the top edge of the top anchor ring 21 is preferably bevelled as at 28 to facilitate the movement of tools and the like into the central passageway through the interliner. Suitable reinforcing means such as fabric 29 may he moulded into the body of the interliner at that section held between the inner and outer shells 24 and 25. Other fabric reinforcing may be included in the interliner body to increase the toughness of the rubber-like resilient tubing. However, it is to be understood that such fabric must be laid within the interliner diagonally or on a bias as indicated at 30 in broken lines, at FIG. l, in order to yield with the pull of the interliner whenever the unit is stretched to reduce its diameter for insertion into or removal from a casing.

The interliner requires a substantial force to properly stretch it and a rugged extender tool is required. One form of such tool is illustrated at FIGS. 2, 3 and 4 and this extender E is formed substantially as a hydraulic piston-cylinder assembly adapted to be suspended from a cable 31 at the top of the unit. The extender E has a diameter such that it may easily slide into the interliner 20 from the top with the piston 32 being directed downwardly. This piston 32 has an enlarged foot 33 which is adapted to bear upon and against the shoulder 27 of the bottom anchor ring 22.

This piston 32 is incased within a cylinder 34 which forms the body of the extender with the length of the unit when retracted, being such as to set within the interliner 20 With the head 35 of the cylinder at the top of the interliner. The head 35 includes an annular slot 36 above the main body of the cylinder A sectioned expander ring 37 is mounted in this slot 36 with an annular gasket 38 within the slot 36. The slot 36 behind the ring 37 forms a chamber and passageways 39 communicate from the slot chamber 36 to a central pocket 40 so that fluid pressure within the pocket 40 acts to extend the expansion ring from the slot 36 and move it into position against the shoulder 26 at the top anchor ring as shown clearly at FIG. 3.

Means for imparting fluid under pressure into the pocket 40 and into the chamber of cylinder 34 to extend the piston may be from any conventional source as by a tiuid pressure line or pump (not shown) which may be attached to a connection 41 at the top of the unit.

When the unit is ready to be lowered into a well the interliner is first stretched at the surface of the well by the extender E. After it is lowered into the shaft the piston 32 and expansion ring 36 may be retracted for release of the extender 4from the interliner by release of iluid pressure. To effect such release, the fitting 41 includes a valve 42 which may be opened lby a time delay mechanism 43. When the interliner is lowered into the Well shaft to the selected level it may simply remain at the position until mechanism 43 opens the valve 42 and releases pressure Within the extender to retracted the piston and expansion ring 37.

In order to recover a previously set interliner, the opposite procedure follows. A retracted extender E is lowered in the well until the foot 33 rests on the bottom shoulder 27. A pressured fluid source connected to fitting 41 then effects expansion of the piston 32 and ring 36. Since it is desirable to expand thering 36 ahead of extending the piston the pocket 40 may be partially cut off from the cylinder chamber above the piston as by a wall section 44 having a restrictive communicating orifice 45 between the two chambers. Therefore, whenever fluid under pres- Sure is fed to the unit through connection 41 the pressure will build up in pocket 40 ahead of building up in the cylinder 34 to first expand the ring 37.

Various alternative constructions of the unit are illustrated at FIGS. 5 through 9. The unit at FIG. 5 is constructed substantially the same as hereinbefore described and the extender E is likewise similar except that it includes a spiral array of flutes 46 on the piston 32' which react with stubs 47 at the base of the cylinder 34 to give the piston a twisting motion as it is extended. A piston foot 33 and the expansion ring 37 will be held against the respective shoulders 27 and 26 by friction as the expansion progresses or by lugs (not shown) on the gripping surfaces. This rotating-stretching movement will not only stretch, but will also impart a twisting action to the interliner 20 and thereby reduce the diameter of the interliner by twisting as well as by stretching.

FIG. 6 shows a modified form of an interliner. This interliner 20a is formed by a shell 48 of rubber-like material such as neoprene, having a diameter slightly greater than the diameter of the casing which it is to be inserted into. Within this shell there is a tightly wound spring or spiral 49 of high-strength; rigid material such as spring steel which will expansively react with considerable force when inserted and held in a casing shaft.

At the top end of this spring reinforced shell there is a top shoulder ring 5f) of sufficient diameter to permit an extender tool to be inserted into the unit for expansion of the unit while at the bottom end of this unit there is a bottom shoulder ring 51 of smaller diameter adapted to be contacted by the foot or base of the extender unit in the manner hereinbefore described. This spring reinforced shell is thus inserted into and removed from casing in substantially the same manner as that hereinbefore described and it is especially adapted for use with a unit similar to the extender E at FIG. 5 which will partially twist in a manner which rotates the coils 49 to a smaller diameter.

The unit illustrated at FIG. 7 is an interliner which is adapted for permanent installation in a well casing or for installation where the interliner 2Gb can be removed only by being cut out of the casing section when it has served its purpose. The cutting operation can be performed by use of a simple grapple shaped knife or the like. This interliner 201) is formed of resilient material such as hereinbefore described, but each end 52 is bevelled and does not include an anchor ring or the like to permit it to be gripped and stretched once it is inserted and set in the casing.

It is contemplated that this interliner 2Gb will be stretched upon a fixed extender E" before it is inserted into the well and after it is lowered to the proper position in the shaft it will be disconnected from the extender. The extender E illustrated at FIGS. 8 and 9 consists of two head sections 53 and 54 separated by a central cylindrical post section 55 of smaller diameter. This interliner 20b is stretched over each head 53 and 54 and is secured in position as by clamps 56 about the ends of the interliner and over the head sections. In order to cut the interliner Zb loose, there is located a circular array of circular knives 57 which bear against the inclined abutment 58 at the inner face of each head sections 53 and 54. These knives are actuated to spread apart by piston-like sleeves S9 which move upon the post l 55 and against the knives 57. The knives 57 move against the abutments 58 and thence outwardly and into the body of the interliner 20b at each end thereof. The sleeves are incased within a central cylinder 60' and each sleeve may be actuated as by a powder charge 61 Within the cylinder that is set off electrically.

In use this permanent unit is lowered into a well casing to a selected depth. The powder charge is then ignited to move the sleeves 59 to extend the knives 57 and sever the interliner from the head sections 53 and 54. The final diameter of this interliner in the pipe is greater than the stretched diameter to such a degree that the extender E may be removed past the interliner 2Gb when flexed outwardly and against the Wall of the pipe as indicated by broken lines at FIG. 8.

While I have described my invention in considerable detail, it is obvious that others skilled in the art can devise and build alternate and equivalent constructions which are within the scope and spirit of my invention and 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.

I claim:

l. A method of using a hollow resilient tubular interliner for blocking off passageways extending transversely through a selected portion of the |wall of a pipe casing to prevent fluid flow through the passageways, wherein said casing has an internal diameter less than the normal external diameter of the interliner, said method including the steps of releasably gripping and pulling with an independent stretching means the ends of the interliner to stretch the interliner longitudinally to increase its length and reduce its external diameter to less than the internal diameter of the casing, positioning Said interliner as stretched and the stretching means within the casing adjacent said selected portion of the Wall of the casing and over the passageways extending therethrough, then while said interliner is so positioned, releasing the gripping by the stretching means at the ends of the interliner to permit the interliner to return toward its normal length and external diameter and expand into engagement with said given portion of the Wall to close off the passageways extending therethrough, and then removing the stretching means from the casing and past the interliner.

2. The method defined in claim l including the step of twisting the interliner as it is being stretched.

3. A casing interliner comprising a tubular length of resilient material adapted to be reduced in diameter when under tension and an anchor ring at each end of the tube, at least one anchor ring having a shoulder within the tube adapted to be engaged by a tension producing apparatus, said shoulder extending radially inwardly past the inner wall of said tube when said tube is both tensioned and in normal condition.

4. A casing interliner comprising a tubular length of resilient material having a selected diameter which is adapted to be reduced when under tension and having a reduced-diameter end portion, an anchor ring at each end of the tube and a shoulder on each anchor ring within the tube adjacent to its end of the tube adapted to be engaged by a tension-producing apparatus, the shoulder on at least one of said anchor rings extending radially inwardly, past the inner wall of said tube when said tube is both tensioned and in normal condition.

5. The interliner defined in claim 4 including a reinforcing spring coil within the body thereof.

6. The interliner defined in claim 4 including a webbing reinforcing biased to the axis of the interliner.

7. The interliner defined in claim 4, wherein said shoulders are formed as annular surfaces.

8. The interliner defined in claim 4, wherein said shoulders are formed as annular internal flanges.

9. In combination with a pipe casing having a given internal diameter, a casing interliner comprising a tubular section of resilient material whose external diameter is normally greater than the internal diameter of the casing but is adapted to be resiliently constricted to an external diameter less than the internal `diameter of the casing when under tension and to compressively grip the casing wall when within the casing, and an anchor ring at each end of the tube, each anchor ring having an internal shoulder, said ring and tube end having a diameter less 2' than the casing diameter and being adapted to be gripped at the shoulder to be placed under tension, the shoulder of the anchor ring at at least one end of said tube extending radially inwardly, past the inner wall of said tube when said tube is both tensioned and in normal condition.

10. A setting apparatus for a resilient tub-shaped interliner adapted to be set in a casing, adapted to hold the interliner under tension to reduce its diameter and to release the interliner as Iwhen it is placed in a casing, and comprising a post section having a head at each end thereof with each end of the interliner tube adapted to be connected to a head and with the interliner being in a prestretched condition and under tension and a normallyretracted disconnect means at at least one head adapted to extend and disconnect the liner from the head, a signal-responsive actuator means adapted to actuate and extend the disconnect means at the head responsive to a signal impulse means and means for creating a signal impulse.

l1. The combination defined in claim 10 wherein said disconnect means include knives adjacent to each head adapted to tlair outwardly and to cut off the interliner from the head.

12. The combination defined in claim 11 including a piston means in the post adapted to extend the knives responsive to piston movement, means within the piston means adapted to move the pistons including a powder charge and means for igniting the same.

13, A stretching tool for a resilient tube-shaped inner liner having a shoulder at each end thereof and being adapted to be stretched to reduce its diameter, comprising an elongated extensible piston-cylinder unit adapted to be placed within the liner, a gripping means laterally outstanding from each end of the piston-cylinder unit adapted to grip the shoulder of the liner and to hold the same when the unit is extended, at least one of gripping means being laterally retractable to release and permit removal of the stretching tool from the liner.

14. The tool dened in claim 13 wherein the piston- Cylinder unit is spiraled with the piston being adapted to rotate with respect to the cylinder as it is extended therefrom and to spirally twist the inner-liner as it stretches the same.

15. In the tool dened in claim 13 wherein said pistoncylinder unit includes a uid pressure line to `the cylinder, and wherein said gripping means includes an annular slot at the end of cylinder, an expander ring within the slot, and a fluid passageway to the slot communicating with the uid line whereby said expander ring is adapted to expand responsive to movement of uid under pressure into the fluid pressure line, whereby the expander ring is adapted to move against a shoulder to grip the same when expanded, and to retract responsive to reduction of fluid pressure whereby to release its grip from the shoulder.

16. In the tool dened in claim 15 a fluid line to the piston-cylinder unit, a valve in the line, adapted to be closed when the piston-cylinder unit is extended and means for operating the valve to open the same to permit the unit to retract.

References Cited in the tile of this patent UNITED STATES PATENTS 790,208 Hubbard May 16, 1905 2,138,156 Halliburton Nov. 29, 1938 2,446,661 Murdock Aug. 10, 1948 2,707,999 Ragan May 10, 1955 2,851,112 Buck Sept. 9, 1958 FOREIGN PATENTS 27,764 Austria Mar. 1l, 1907

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