Abstract:
A flexible swage comprises a swage cup and a support receivable in a swage cup. The swage cup and support are separable in order to promote distinct purposes. The first purpose is to allow the swage to act as such and reform a deformed junction when the support is engaged with the swage cup thus supporting it against deflection. The second purpose is to remove the swage from the deformed junction at which time deflection in the swage cup is beneficial. Thus, the support is removed from engagement with the swage cup thereby allowing the swage cup to deform and be removed from the reformed junction more easily.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/117,845 filed Jan. 29, 1999, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to oilfield downhole operations. More particularly, the invention relates to a swage device for reforming a deformable junction in a deviated wellbore. 
     2. Prior Art 
     As is well known to those of skill in the art, reformable deformed junctions have been known to the oilfield art. The benefit of a deformed junction is that the junction is easily transported through the casing of a wellbore or an open hole wellbore to its final destination at a junction between a primary and lateral borehole. Once the junction is properly positioned, it is reformed into a Y-shaped junction to assist in completing the wellbore. In the fully reformed condition of the junction, the outer dimensions are generally greater than the inside diameter (ID) of the casing or open hole. Thus, of course, it would be rather difficult to install the junction in its undeformed condition. Many methods have been used to reform the deformed junction in the borehole. One of the prior art methods has been to employ a swaging device. Swaging devices generally comprise a conical or frustoconical hardened member having an outside diameter (OD) as large as possible while being passable through the wellbore casing or the open hole. This swage is forced to travel through a previously positioned deformed junction whereby the junction is reformed into an operational position. Where the junction is located in a vertical or near vertical wellbore, setdown weight alone often is sufficient to generate the approximately 100,000 pounds of force required to reform the junction. Where the deformed junction is being placed in a highly deviated wellbore or a horizontal wellbore, however, setdown weight might not be sufficient to force the swage device through the junction. In this event, one of skill in the art will recognize the hydraulic procedure alternative to setdown weight. This hydraulic procedure includes an expansion joint located above the swage device, a drill tube anchor located above the expansion joint, and a ball seat located below the expansion joint such that by dropping a ball, pressure can be applied to the tubing string. This applied pressure forces the expansion joint to expand downhole, which in turn forces the swage device through the junction. Expansion joints are well known in the art, as are anchors and ball seats. 
     As also will be recognized by one of ordinary skill in the art, there is a significant drawback to the prior art swaging devices. The metal of the junction has a certain amount of resilience such that after the swage device has been forced through the junction, reforming the same, the junction itself will rebound to a smaller ID than the OD of the swage device by several thousandths of an inch. Because of the rebound it requires nearly as much lifting force on the swage device to remove it from the wellbore as is needed to initially force the swage through the deformed junction. This can be as much as 100,000 pounds. Although a drilling rig can easily pull ten times this weight, in a highly deviated or horizontal wellbore, the friction created on the curvature of the well can be high enough to absorb all of the force imparted at the surface and leave none available for the swage. Thus, the tool is stuck. The amount of force necessary to pull the swage through the newly reformed junction can also be sufficient to damage other well tools or junctions. Such damage can of course cost significant sums of money to repair and require significant time both to diagnose and to repair. Thus, the art is in need of a swage device that does not carry the drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     The above-identified drawbacks of the prior art are overcome or alleviated by the flexible swage device of the invention. 
     The invention avoids the above set forth drawback by creating a two-part swage device comprising a support and a swage cup. The support is engaged with the swage cup during the swaging operation. The swage cup is moveable such that after the swaging operation is complete, the swage cup can be moved to a position where it is unsupported by the support and is therefore allowed to deflect several thousandths of an inch toward the mandrel. This deflection will significantly reduce drag on the swage cup through the reformed junction (and any other junctions uphole of the subject junction) during removal of the swage device from the wellbore. In an alternate embodiment, the swage cup contains longitudinal slots cut into it to impart increased flexibility characteristics to the swage cup. The flexible swage device of the invention is employable in place of a conventional swage, the function of which being fully assimilated in the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: 
     FIG. 1 is a side view of the invention in the swage position; and 
     FIG. 2 is a side view of the invention wherein the swage cup has been sheared to a second position, which is the retrieving position; 
     FIG. 3 is a cross section view of a second embodiment of the invention; 
     FIG. 4 is a perspective view of the swage cup; and 
     FIG. 5 is a perspective view of an alternate embodiment of the swage cup. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a flexible swage in the swaging position is shown generally at  10 . The invention is illustrated mounted on a mandrel  11  by a regular threaded connection  12  and a plurality of set screws  14 . Each set screw  14  is received in a groove  16 , the combination of which with screw thread  12  prevents movement of a support  18 . Support  18  is preferably a frustoconical annular element of a single piece although multiple pieces could be used to achieve the result of the invention. Support  18  is provided with at least one port  20  (preferably several ports  20 ) that exits support  18  uphole of a point of contact of the swage device with the inner wall of a junction being deformed (not shown). Port  20  also intersects a bore  22  of which there may be several and preferably will be as many as there are ports  20 , which extends through support  18  to a downhole end  24  thereof. Bore  22  is open to annular space  26  as illustrated. As should be understood, there may be several bores  22  that open into annular space  26 . Support  18  can be seen in the drawing (FIG. 1) to matingly receive and support a swage member  27 . 
     Referring now to FIG. 4, one embodiment of the swage member of the invention is shown separately from other components of the invention. The swage member is numeralled  27 . Swage member  27  comprises a swage cup  28  and a swage base  30  and is a frustoconical annular element preferably of a single piece. Alternately, multiple pieces could be used to form swage member  27 . In either case, swage cup  28  extends upwardly and outwardly from swage cup base  30 . A hole  29  extends axially through swage cup  28  and swage cup base  30  and is of a size sufficient to allow swage member  27  to receive mandrel  11 . An uphole end  33  of swage cup  28  is substantially hollowed out and configured to matingly accommodate support  18 , thereby preventing the deflection of the outer perimeter of swage cup  28  toward mandrel  11 . 
     Turning now to FIG. 5, an alternate embodiment of the swage member of the invention is illustrated generally at  227 . This alternate embodiment comprises swage cup  228  and swage cup base  230 . Swage cup  228  is still of a generally frustoconical shape and is still preferably fabricated from a single piece of material, as in the previous embodiment. However, swage cup  228  contains a plurality of longitudinal slots  235  cut therein and extending toward swage cup base  230 . Slots  235  render swage cup  228  more flexible than the first described embodiment. The greater flexibility, it will be understood, is due to the kerf width of slots  235 . Since it is possible during compression of swage cup  228  to “close” the kerf of slots  235 , a greater reduction in the outside diameter of swage cup  228  is achievable. Slots  235  make retrieval of the tool easier without compromising the swaging action of the tool in the first instance. 
     Referring back to FIG. 1, swage cup base  30  includes bore  32  open on a downhole end  34  of swage cup base  30  to the well fluid downhole of a contact area  31  of swage cup  28  with the inside dimension of a deformable junction  33  (shown in phantom lines). Bore  32  extends to an uphole end  36  which communicates with annular space  26 . Annular space  26  ensures communication between bore  32  and bore  22  thus effecting through-passage of well fluids from below contact area  31  of swage cup  28  with the inside dimension of deform able junction  33  (effectively a metal-to-metal seal) to the outlet of port  20  above contact point  31 . A means for fluid flow (such as bore  22 ) through swage  10  is necessary to provide an outlet for the build up of fluid pressure downhole of swage cup  28 . By providing a bore through swage cup  28 , the conditions allowing for the formation of this hydraulic lock under swage cup  28 , which would otherwise hinder and possibly prevent movement of swage  10  through the junction, are defeated. 
     Swage cup  28  and swage cup base  30  are located on mandrel  11  by shear screws  38  only. Swage cup  28  and swage cup base  30  are preferably a single annular component that is slideable along mandrel  11 . Therefore, some means of holding swage cup  28  and swage cup base  30  in the swaging position on support  18  is needed for the invention to function as intended. One embodiment of such means is through the use of shear screws  38 , which are received in groove  40 . It will be recognized by one of ordinary skill in the art that since shear screws  38  are the only means in this embodiment which hold swage cup  28  and swage cup base  30  in place, swage cup  28  and swage cup base  30  may rotate 360° around mandrel  11  relatively freely. The significance of annular space  26  then is to ensure that bore  32  is in fluid communication with bore  22  regardless of the orientation swage cup  28  and swage cup base  30  have relative to support  18 . 
     In the condition shown in FIG. 1, one of ordinary skill in the art will appreciate that as swage  10  is forced downhole, it will quite effectively reform a deformed junction similarly to prior art swages. Once the reformation is complete and it is desirable to remove swage  10  from the wellbore, an upward pull is necessary. Referring now to FIG. 2, upon pulling the tool in the upward direction, a point  42  of swage cup  28  will contact the inner walls of the junction due to the resilience of the junction as discussed hereinbefore. The pressure on point  42  will tend to prevent swage  10  from moving uphole. This force is translated through swage cup  28  and swage cup base  30  to screws  38 , which will then shear under that force. One of skill in the art will recognize that the particular amount of force required to shear screws  38  is engineerable in advance and should be matched to an appropriate amount of force to indicate that withdrawal of the tool is desired. Upon shearing of screws  38 , swage cup base  30  and swage cup  28  move downhole until downhole end  34  of swage cup base  30  is in contact with an uphole end  44  of a swage stop  46 . It should be briefly noted at this point that swage stop  46  is connected to mandrel  11  via a regular thread  48  and a plurality of set screws  50 . Swage stop  46  further includes an o-ring  52  to seal swage stop  46  against mandrel  11 . 
     Upon shifting swage cup  28  and swage cup base  30  downhole into contact with uphole end  44  of swage stop  46 , a gap  54  is formed between swage cup  28  and support  18 . Because of gap  54 , continued pulling on swage  10  causes swage cup  28  to deflect inwardly toward mandrel  11  to a degree which is sufficient to allow swage member  27  to slide through the junction. The deflection of swage cup  28  is typically several thousandths of an inch. Gap  54  may be as small as several thousandths of an inch, or it may be larger. The deflection of swage  28  will merely be what is necessary for swage  10  to move through the junction at a significantly reduced force as it is being withdrawn from the well. 
     In a second embodiment of the invention, referring now to FIG. 3, the general mode of operation of the swage remains the same, but the way in which it is carried out is slightly different. Since each of the components of this embodiment is slightly different than each of their counterparts in the first described embodiment, new numerals are used for each. 
     A mandrel  111  supports a swage  110 , which is activated through the movement of mandrel  111 . In the running position (shown), a swage ring support  114  is in position to support a swage ring  116 . Both swage ring support  114  and swage ring  116  in this embodiment “float” on mandrel  111  (i.e., they are not attached to mandrel  111 ). At the uphole end of mandrel  111 , swage ring support  114  is prevented from moving further uphole by a retaining ring  118 . Retaining ring  118  is threadedly connected to mandrel  111  by a thread  120  and prevented from moving on thread  120  by at least one set screw  122 , which is received in a groove  124 . In a preferred embodiment, mandrel  111  is “turned down” to form a shoulder  126  extending to the downhole end of swage  110  and is configured such that retaining ring  118  firmly abuts shoulder  126 . Configuring mandrel  111  to contain shoulder  126  provides more annular space between the “turned down” surface of mandrel  111  and the borehole or junction so that thicker swage components may be used. The “turn down” of shoulder  126  also lends extra stability to retaining ring  118 . 
     Swage support  114  abuts retaining ring  118  at interface  130  and includes fluid bypass  132 . Support for swage ring  116  is along interface  134 . As a unit, support  114  and swage ring  116  function as their counterparts did in the previous embodiment and indeed as do those of the prior art to reform a deformed junction. It is with the recovery of swage  110  that its unique construction is evident and beneficial. It should be noted that swage ring  116  includes at least one fluid bypass conduit  138  that communicates with an annulus  140 . 
     Downhole of swage ring  116  is a shear ring  142 . Swage ring  116  abuts shear ring  142  at interface  144 . Shear ring  142  is prevented from longitudinal movement on mandrel  111  by a plurality of shear screws  146 , which extend into groove  148  on mandrel  111 . Shear ring  142 , together with retaining ring  118 , maintains swage ring support  114  and swage ring  116  in the operative running and reforming position. It should be noted that slots  150  are provided on both the uphole and downhole sides of shear ring  142  in a preferred embodiment. While only the uphole end of shear ring  142  requires slots  150  to allow fluid bypass, placing slots  150  on both ends avoids the possibility that swage  110  might be assembled backwards. 
     At the downhole end of swage  110  in FIG. 3 (i.e., the right side of the drawing), a dual function nose swage  152  is threadedly attached to mandrel  111  at a thread  154  and locked in place by at least one set screw  156  received in groove  158 . Nose swage  152  acts to prevent shear ring  142  from falling off the end of mandrel  111  after shear screw(s)  146  are sheared and also acts as a pre-reforming swage to open up tightly deformed junctions. 
     In the operational condition, with shear screw(s)  146  intact, the space between uphole end  160  of nose swage  152  and downhole end  162  of shear ring  142  is preferably sufficient to allow full shearing of shear screw(s)  146  by displacement of shear ring  142  in the downhole direction before the noted surfaces touch. This prevents a partial shearing condition which may impede performance to some degree. The partial shearing, however, should not completely prevent swage  110  from performing. 
     Once swage  110  has been forced through the junction being reformed it will be withdrawn or pulled uphole. In the event that the swage encounters significant resistance, the features of the invention will be set in motion. Since both the swage ring support  114  and swage ring  116  are not connected to mandrel  111 , resistance provided by the deformed junction is translated directly to shear screw(s)  146 . At a predetermined amount of force, screw(s)  146  will shear and allow mandrel  111  to move uphole. At this point, support  114  has not been moved relative to swage ring  116 . Thus, the frictional engagement therebetween is rendered independent and not cumulative with respect to the amount of force necessary to shear screw(s)  146 . Upon the movement of mandrel  111  uphole, a snap ring  164  impacts a shoulder  166  on support  114  and will move support  114  out of its support position under swage ring  116 . This, as in the previous embodiment, allows swage ring  116  to flex, thereby allowing swage  110  to be retrieved. In practice, the disengagement of support  114  with swage ring  116  is assisted by a jarring action that normally results from the sudden shear of screw(s)  146 . It should be noted, however, that a straight pull on swage  110  would also dislodge support  114  from swage ring  116 . The jarring action is a likely mode of operation; however, it is not a required mode of operation. Overcoming the friction generated by flexible swage ring  116  being urged into contact with support  114  as a result of contact between the swage ring  116  and inner walls of the junction is all that is necessary. After shearing, swage ring  116  and shear ring  142  will rest on nose swage  152  while support shoulder  166  will rest on snap ring  164 . In this condition, support for swage ring  116  is not available and it is free to flex allowing swage  110  to be recovered from the junction. Commonly, the flexing that will occur is into a slight oval shape. 
     It should be appreciated that in both embodiments of the invention the shear release or other release mechanism may not be used in all conditions. Swage  10  may pull through the junction without needing to be flexible. Because these tools incorporate the invention, the tools are retrieved whether or not swage  10  gets stuck in the junction. If swage  10  does get stuck in the junction, shear screw(s)  146  will shear on continued pickup of swage  10  and swage  10  will operate as hereinbefore described. 
     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.