Abstract:
A method for securing and sealing one tubular to another downhole facilitates cementing prior to sealing and allows for suspension of one tubular in the other by virtue of pipe expansion techniques.

Description:
FIELD OF THE INVENTION  
         [0001]    The field of this invention relates to suspending one tubular in another, especially hanging liners which are to be cemented.  
         BACKGROUND OF THE INVENTION  
         [0002]    In completing wellbores, frequently a liner is inserted into casing and suspended from the casing by a liner hanger. Various designs of liner hangers are known and generally involve a gripping mechanism, such as slips, and a sealing mechanism, such as a packer which can be of a variety of designs. The objective is to suspend the liner during a cementing procedure and set the packer for sealing between the liner and the casing. Liner hanger assemblies are expensive and provide some uncertainty as to their operation downhole.  
           [0003]    Some of the objects of the present invention are to accomplish the functions of the known liner hangers by alternative means, thus eliminating the traditionally known liner hanger altogether while accomplishing its functional purposes at the same time in a single trip into the well. Another objective of the present invention is to provide alternate techniques which can be used to suspend one tubular in another while facilitating a cementing operation and still providing a technique for sealing the tubulars together. Various fishing tools are known which can be used to support a liner being inserted into a larger tubular. One such device is made by Baker Oil Tools and known as a “Tri-State Type B Casing and Tubing Spear,” Product No. 126-09. In addition to known spears which can support a tubing string for lowering into a wellbore, techniques have been developed for expansion of tubulars downhole. Some of the techniques known in the prior art for expansion of tubulars downhole are illustrated in U.S. Pat. Nos. 4,976,322; 5,083,608; 5,119,661; 5,348,095; 5,366,012; and 5,667,011.  
         SUMMARY OF THE INVENTION  
         [0004]    A method for securing and sealing one tubular to another downhole facilitates cementing prior to sealing and allows for suspension of one tubular in the other by virtue of pipe expansion techniques. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    FIGS.  1 - 4  are a sectional elevation, showing a first embodiment of the method to suspend, cement and seal one tubular to another downhole, using pipe expansion techniques.  
         [0006]    FIGS.  5 - 11   a  are another embodiment creating longitudinal passages for passage of the cementing material prior to sealing the tubulars together.  
         [0007]    FIGS.  12 - 15  illustrate yet another embodiment incorporating a sliding sleeve valve for facilitating the cementing step.  
         [0008]    FIGS.  16 - 19  illustrate the use of a grapple technique to suspend the tubular inside a bigger tubular, leaving spaces between the grappling members for passage of cement prior to sealing between the tubulars.  
         [0009]    FIGS.  20 - 26  illustrate an alternative embodiment involving a sequential flaring of the inner tubular from the bottom up.  
         [0010]    FIGS.  28 - 30  illustrate an alternative embodiment involving fabrication of the tubular to be inserted to its finished dimension, followed by collapsing it for insertion followed by sequential expansion of it for completion of the operation. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]    Referring to FIG. 1, a tubular  10  is supported in casing  12 , using known techniques such as a spear made by Baker Oil Tools, as previously described. That spear or other gripping device is attached to a running string  14 . Also located on the running string  14  above the spear is a hydraulic or other type of stroking mechanism which will allow relative movement of a swage assembly  16  which moves in tandem with a portion of the running string  14  when the piston/cylinder combination (not shown) is actuated, bringing the swage  16  down toward the upper end  18  of the tubular  10 . As shown in FIG. 1 during run-in, the tubular  10  easily fits through the casing  12 . The tubular  10  also comprises one or more openings  20  to allow the cement to pass through, as will be explained below. Comparing FIG. 2 to FIG. 1, the tubular  10  has been expanded radially at its upper end  18  so that a segment  22  is in contact with the casing  12 . Segment  22  does not include the openings  20 ; thus, an annular space  24  exists around the outside of the tubular  10  and inside of the casing  12 . While in the position shown in FIG. 2, cementing can occur. This procedure involves pumping cement through the tubular  10  down to its lower end where it can come up and around into the annulus  24  through the openings  20  so that the exterior of the tubular  10  can be fully surrounded with cement up to and including a portion of the casing  12 . Before the cement sets, the piston/cylinder mechanism (not shown) is further actuated so that the swage assembly  16  moves further downwardly, as shown in FIG. 3. Segment  22  has now grown in FIG. 3 so that it encompasses the openings  20 . In essence, segment  22  which is now against the casing  12  also includes the openings  20 , thereby sealing them off. The seal can be accomplished by the mere physical expansion of segment  22  against the casing  12 . Alternatively, a ring seal  26  can be placed below the openings  20  so as to seal the cemented annulus  24  away from the openings  20 . Optionally, the ring seal  26  can be a rounded ring that circumscribes each of the openings  20 . Additionally, a secondary ring seal similar to  26  can be placed around the segment  22  above the openings  20 . As shown in FIG. 3, the assembly is now fully set against the casing  12 . The openings  20  are sealed and the tubular  10  is fully supported in the casing  12  by the extended segment  22 . Referring to FIG. 4, the swage assembly  16 , as well as the piston/cylinder assembly (not shown) and the spear which was used to support the tubular  10 , are removed with the running string  14  so that what remains is the tubular  10  fully cemented and supported in the casing  12 . The entire operation has been accomplished in a single trip. Further completion operations in the wellbore are now possible. Currently, this embodiment is preferred.  
         [0012]    FIGS.  5 - 12  illustrate an alternative embodiment. Here again, the tubular  28  is supported in a like manner as shown in FIGS.  1 - 4 , except that the swage assembly  30  has a different configuration. The swage assembly  30  has a lower end  32  which is best seen in cross-section in FIG. 8. Lower end  32  has a square or rectangular shape which, when forced against the tubular  28 , leaves certain passages  34  between itself and the casing  36 . Now referring to FIG. 7, it can be seen that when the lower end  32  is brought inside the upper end  38  of the tubular  28 , the passages  34  allow communication to annulus  40  so that cementing can take place with the pumped cement going back up the annulus  40  through the passages  34 . Referring to FIG. 8, it can be seen that the tubular  28  has four locations  42  which are in contact with the casing  36 . This longitudinal surface location in contact with the casing  36  provides full support for the tubular  28  during the cementing step. Thus, while the locations  42  press against the inside wall of the casing  36  to support the tubular  28 , the cementing procedure can be undertaken in a known manner. At the conclusion of the cementing operation, an upper end  44  of the swage assembly  30  is brought down into the upper end  38  of the tubular  28 . The profile of the upper end  44  is seen in FIG. 10. It has four locations  46  which protrude outwardly. Each of the locations  46  encounters a mid-point  48  (see FIG. 8) of the upper end  38  of the tubular  28 . Thus, when the upper end  44  of the swage assembly  30  is brought down into the tubular  28 , it reconfigures the shape of the upper end  38  of the tubular  28  from the square pattern shown in FIG. 8 to the round pattern shown in FIG. 12. FIG. 11 shows the running assembly and the swage assembly  30  removed, and the well now ready for the balance of the completion operations. The operation has been accomplished in a single trip into the wellbore. Accordingly, the principal difference in the embodiment shown in FIGS.  1 - 4  and that shown in FIGS.  5 - 12  is that the first embodiment employed holes or openings to facilitate the flow of cement, while the second embodiment provides passages for the cement with a two-step expansion of the upper end  38  of the tubular  28 . The first step creates the passages  34  using the lower end  32  of the swage assembly  30 . It also secures the tubular  28  to the casing  36  at locations  42 . After cementing, the upper end  44  of the swage assembly  30  basically finishes the expansion of the upper end  38  of the tubular  28  into a round shape shown in FIG. 12. At that point, the tubular  28  is fully supported in the casing  36 . Seals, as previously described, can optionally be placed between the tubular  28  and the casing  36  without departing from the spirit of the invention.  
         [0013]    Another embodiment is illustrated in FIGS.  12 - 15 . This embodiment has similarities to the embodiment shown in FIGS.  1 - 4 . One difference is that there is now a sliding sleeve valve  48  which is shown in the open position exposing openings  50 . As shown in FIG. 12, a swage assembly  52  fully expands the upper end  54  of the tubular  56  against the casing  58 , just short of openings  50 . This is seen in FIG. 13. At this point, the tubular  56  is fully supported in the casing  58 . Since the openings  50  are exposed with the sliding sleeve valve  48 , cementing can now take place. At the conclusion of the cementing step, the sliding sleeve valve  48  is actuated in a known manner to close it off, as shown in FIG. 14. Optionally, seals can be used between tubular  56  and casing  58 . The running assembly, including the swage assembly  52 , is then removed from the tubular  56  and the casing  58 , as shown in FIG. 15. Again, the procedure is accomplished in a single trip. Completion operations can now continue in the wellbore.  
         [0014]    FIGS.  16 - 19  illustrate another technique. The initial support of the tubular  60  to the casing  62  is accomplished by forcing a grapple member  64  down into an annular space  66  such that its teeth  68  ratchet down over teeth  70 , thus forcing teeth  72 , which are on the opposite side of the grappling member  64  from teeth  68 , to fully engage the inner wall  74  of the casing  62 . This position is shown in FIG. 17, where the teeth  68  and  70  have engaged, thus supporting the tubular  60  in the casing  62  by forcing the teeth  72  to dig into the inner wall  74  of the casing  62 . The grapple members  64  are elongated structures that are placed in a spaced relationship as shown in FIG. 17A. The spaces  76  are shown between the grapple members  64 . Thus, passages  76  provide the avenue for cement to come up around annulus  78  toward the upper end  80  of the tubular  60 . At the conclusion of the cementing, the swage assembly  82  is brought down into the upper end  80  of the tubular  60  to flare it outwardly into sealing contact with the inside wall  74  of the casing  62 , as shown in FIG. 18. Again, a seal can be used optionally between the upper end  80  and the casing  62  to seal in addition to the forcing of the upper end  80  against the inner wall  74 , shown in FIG. 18. The running assembly as well as the swage assembly  82  is shown fully removed in FIG. 19 and further downhole completion operations can be concluded. All the steps are accomplished in a single trip.  
         [0015]    FIGS.  20 - 25  illustrate yet another alternative of the present invention. In this situation, the swage assembly  84  has an upper end  86  and a lower end  88 . In the run-in position shown in FIG. 20, the upper end  86  is located below a flared out portion  90  of the tubular  92 . Located above the upper end  86  is a sleeve  94  which is preferably made of a softer material than the tubular  92 , such as aluminum, for example. The outside diameter of the flared out segment  90  is still less than the inside diameter  96  of the casing  98 . Ultimately, the flared out portion  90  is to be expanded, as shown in FIG. 21, into contact with the inside wall of the casing  98 . Since that distance representing that expansion cannot physically be accomplished by the upper end  96  because of its placement below the flared out portion  90 , the sleeve  94  is employed to transfer the radially expanding force to make initial contact with the inner wall of casing  98 . The upper end  86  of the swage assembly  84  has the shape shown in FIG. 22 so that several sections  100  of the tubular  92  will be forced against the casing  98 , leaving longitudinal gaps  102  for passage of cement. In the position shown in FIGS. 21 and 22, the passages  102  are in position and the sections  100  which have been forced against the casing  98  fully support the tubular  92 . At the conclusion of the cementing operation, the lower segment  88  comes into contact with sleeve  94 . The shape of lower end  88  is such so as to fully round out the flared out portion  90  by engaging mid-points  104  of the flared out portion  90  (see FIG. 22) such that the passages  102  are eliminated as the sleeve  94  and the flared out portion  90  are in tandem pressed in a manner to fully round them, leaving the flared out portion  90  rigidly against the inside wall of the casing  98 . This is shown in FIG. 23. FIG. 25 illustrates the removal of the swage assembly  84  and the tubular  92  fully engaged and cemented to the casing  98  so that further completion operations can take place. FIGS. 24 and 26 fully illustrate the flared out portion  90  pushed hard against the casing  98 . Again, in this embodiment as in all the others, auxiliary sealing devices can be used between the tubular  92  and the casing  98  and the process is done in a single trip.  
         [0016]    Referring now to FIGS.  27 - 30 , yet another embodiment is illustrated. Again, the similarities in the running in procedure will not be repeated because they are identical to the previously described embodiments. In this situation, the tubular  106  is initially formed with a flared out section  108 . The diameter of the outer surface  110  is initially produced to be the finished diameter desired for support of the tubular  106  in a casing  112  (see FIG. 28) in which it is to be inserted. However, prior to the insertion into the casing  112  and as shown in FIG. 28, the flared out section  108  is corrugated to reduce its outside diameter so that it can run through the inside diameter of the casing  112 . The manner of corrugation or other diameter-reducing technique can be any one of a variety of different ways so long as the overall profile is such that it will pass through the casing  112 . Using a swage assembly of the type previously described, which is in a shape conforming to the corrugations illustrated in FIG. 28 but tapered to a somewhat larger dimension, the shape shown in FIG. 29 is attained. The shape in FIG. 29 is similar to that in FIG. 28 except that the overall dimensions have been increased to the point that there are locations  114  in contact with the casing  112 . These longitudinal contacts in several locations, as shown in FIG. 29, fully support the tubular  106  in the casing  112  and leave passages  116  for the flow of cement. The swage assembly can be akin to that used in FIGS.  5 - 11  in the sense that the corrugated shape now in contact with the casing  112  shown in FIGS.  29  at locations  114  can be made into a round shape at the conclusion of the cementing operation. Thus, a second portion of the swage assembly as previously described is used to contact the flared out portion  108  in the areas where it is still bent, defining passages  116 , to push those radially outwardly until a perfect full 360° contact is achieved between the flared out section  108  and the casing  112 , as shown in FIG. 30. This is all done in a single trip.  
         [0017]    Those skilled in the art can readily appreciate that various embodiments have been disclosed which allow a tubular, such as  10 , to be suspended in a running assembly. The running assembly is of a known design and has the capability not only of supporting the tubular for run-in but also to actuate a swage assembly of the type shown, for example, in FIG. 1 as item  16 . What is common to all these techniques is that the tubular is first made to be supported by the casing due to a physical expansion technique. The cementing takes place next and the cementing passages are then closed off. Since it is important to allow passages for the flow of cement, the apparatus of the present invention, in its various embodiments, provides a technique which allows this to happen with the tubular supported while subsequently closing them off. The technique can work with a swage assembly which is moved downwardly into the top end of the tubular or in another embodiment, such as shown in FIGS.  20 - 26 , the swage assembly is moved upwardly, out of the top end of the tubular. The creation of passages for the cement, such as  34  in FIG. 8, 76 in FIG. 17A, or  102  in FIG. 22, can be accomplished in a variety of ways. The nature of the initial contact used to support the tubular in the casing can vary without departing from the spirit of the invention. Thus, although four locations are illustrated for the initial support contact in FIG. 8, a different number of such locations can be used without departing from the spirit of the invention. Different materials can be used to encase the liner up and into the casing from which it is suspended, including cement, blast furnace slag, or other materials, all without departing from the spirit of the invention. Known techniques are used for operating the sliding sleeve valve shown in FIGS.  12 - 15 , which selectively exposes the openings  50 . Other types of known valve assemblies are also within the spirit of the invention. Despite the variations, the technique winds up being a one-trip operation.  
         [0018]    Those skilled in the art will now appreciate that what has been disclosed is a method which can completely replace known liner hangers and allows for sealing and suspension of tubulars in larger tubulars, with the flexibility of cementing or otherwise encasing the inserted tubular into the larger tubular.  
         [0019]    The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.