Abstract:
A compliant swage has the ability to change shape to allow clearance of an obstruction while permitting expansion to go on in other areas removed from the obstruction. A series of segments move with respect to each other longitudinally to change overall size. The segments have an additional degree of freedom to change from a round profile of varying diameter to an oblong, elliptical, or an irregular shape so as to compensate in the portion that encounters an obstruction to let the swage pass while at the same time permitting the intended maximum expansion in other portions where conditions permit such expansion.

Description:
PRIORITY INFORMATION 
   This application claims the benefit of U.S. Provisional Application No. 60/450,899 on Feb. 28, 2003. 

   FIELD OF THE INVENTION 
   The field of the invention is expansion of tubulars and more particularly the use of a compliant swage that can expand the tubular while compensating for tight spots where expansion cannot take place. 
   BACKGROUND OF THE INVENTION 
   Tubulars are expanded for a variety of reasons. In the application a patch is expanded to repair cracked casing. In other applications tubulars or liners are expanded to connect to each other or to casing downhole to present a larger cross-sectional area for a segment of the well. In other applications, deformation or a collapse of casing from forces of the surrounding formation needs to be corrected to improve the borehole cross-sectional area in the affected zone. 
   Swages have been used to accomplish this task. Swages are generally a tapered shape coming to a fixed maximum diameter such that when pushed or pulled through the obstructed area results in making the tubular either resume its initial round dimension or expand the tubular into an even larger round dimension. More recently swages that could change circular dimension were disclosed by the inventors of the present invention in a U.S. provisional application filing on Feb. 11, 2002 having Ser. No. 60/356,061. That design allowed connected segments to move longitudinally with respect to each other to vary the circular maximum diameter of the swage. This ability had the advantage of changing size in the face of an obstruction to avoid sticking the swage or overloading the swage driving apparatus. This device had the capability of reducing to a smaller diameter to allow clearing of an obstruction. Its limitation was that if a tight spot adjacent the outside of only a part of the circumference of the tubular to be expanded was encountered, the swage reduced its diameter symmetrically to clear the obstruction. This resulted in a decrease in cross-sectional area beyond the amount necessary to clear the localized obstruction. 
   The present invention presents a compliant swage that has enough range of motion among its components to provide sufficient articulation to let the swage go out of round in profile. This permits a part of the swage to reduce in dimension at the localized obstruction while in the remaining regions where there is no such resistance, the expansion can continue as the swage advances. The net result is a larger cross-sectional area can be obtained than with the prior design and the obstruction can still be cleared. These and other advantages of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment and the claims, which appear below. 
   SUMMARY OF THE INVENTION 
   A compliant swage has the ability to change shape to allow clearance of an obstruction while permitting expansion to go on in other areas removed from the obstruction. A series of segments move with respect to each other longitudinally to change overall size. The segments have an additional degree of freedom to change from a round profile of varying diameter to an oblong, elliptical, or an irregular shape so as to compensate in the portion that encounters an obstruction to let the swage pass while at the same time permitting the intended maximum expansion in other portions where conditions permit such expansion. 

   
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a section view of the swage assembly in the run in position; 
       FIG. 2  is the view of  FIG. 1  in the beginning to swage position; 
       FIG. 3  is a detail of a pair of segments that are upwardly oriented and an adjacent par that is oppositely oriented; 
       FIG. 4  is a section view through lines  2 — 2  of  FIG. 2 ; 
       FIG. 5  is the view of  FIG. 2  showing the expansion proceeding prior to encountering an obstruction; 
       FIG. 6  is the view of  FIG. 5  just as an obstruction is about to be encountered; 
       FIG. 7  is a section view along lines  7 — 7  of  FIG. 2  when an obstruction is encountered; 
       FIG. 8  is a perspective view of two adjacent segments showing how they connect to each other in a tongue and groove manner; 
       FIG. 9  is the view from the opposite end as compared to  FIG. 8 ; 
       FIG. 10  is a perspective view of the assembled segments in the maximum dimension position; 
       FIG. 11  is the view of  FIG. 10  in the minimum dimension position during run in; 
       FIG. 12  shows an alternative embodiment where the segments abut in acrcuate contact and the segments are in a round configuration; 
       FIG. 13  is the view of  FIG. 12  after an obstruction is encountered and the segments have moved to an out of round shape to clear the obstruction; 
       FIG. 14  is an alternate embodiment to  FIG. 3  where a single segment is connected at the T-shaped connection instead of a par of segments; and 
       FIG. 15  is the mating segment to  FIG. 14  in the alternative embodiment to  FIG. 12  where the segments have arcuate edge contact and a single segment rather than a pair is connected at a T-shaped connection. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows the preferred embodiment of the swage apparatus A of the present invention. It has a mandrel  10  with thread  12  for connecting tubing or some other driving mechanism (not shown). Passage  14  has lateral exits  16  and  18  to communicate applied pressure to annular cavities  20  and  22  respectively. Rounding piston  24  is sealed by seals  26  and  28  so that pressure in cavity  20  urges rounding piston  24  toward lower end  30  of the apparatus A. Swage anchor  32  is held at thread  34  to mandrel  10 . Near its lower end  36  there are a plurality of preferably T-shaped openings  38 , although other shapes can be used. 
   Referring to  FIG. 3  swage segments  40  and  42  have C-shaped upper ends  44  and  46  respectively so that when brought together the adjacent upper ends  44  and  46  take on a T-shape that is designed to fit loosely in T-shaped openings  38  in swage anchor  32 . Referring to  FIGS. 1 and 9 , it can be seen that upper ends  44  and  46  respectively include beveled surfaces  48  and  50  onto which the beveled lower end  52  of rounding piston  24  is brought to bear. 
   The assembly that comprises the compliant swage  54  is partially shown in a flattened view in  FIG. 3  and in perspective in  FIG. 11 , during the run in procedure. 
     FIG. 1  illustrates a run in position with preferably no pressure in passage  14 . In that case there is no uphole pressure from piston  64  and segment pairs  56  and  58  are in their lowermost position so that the compliant swage assembly is at its minimum dimension. This position is best seen in the perspective view of  FIG. 11 . Ridgelines  70  and  72  on segment pairs  56  and  58  are longitudinally offset from ridgelines  74  and  76  on segment pairs  40  and  42 . This should be compared with the swaging position shown in  FIG. 10 . In this view, fluid pressure is applied in passage  14  pushing piston  64  uphole and with it segment pairs  56  and  58 . The ridgelines  70 ,  72 ,  74  and  76  align in a circular configuration, as shown in  FIG. 4 . The circular configuration is promoted by the wedging action from beveled lower end  52  of rounding piston  24  forcing the segment pairs  40  and  42  into such a shape. Since all the segment pairs are interconnected, as will be described, the compliant swage assembly  54  as a whole assumes a circular shape for the purpose of swaging at the pre-designated maximum dimension, illustrated in the perspective view of  FIG. 10 . 
     FIG. 1  illustrates a run in position with preferably no pressure in passage  14 . In that case there is no uphole pressure from piston  64  and segment pairs  56  and  58  are in their lowermost position so that the compliant swage assembly is at its minimum dimension. This position is best seen in the perspective view of  FIG. 11 . Ridgelines  70  and  72  on segment pairs  56  and  58  are longitudinally offset from ridgelines  74  and  76  on segment pairs  40  and  42 . This should be compared with the swaging position shown in  FIG. 10 . In this view, fluid pressure is applied in passage  14  pushing piston  64  uphole and with it segment pairs  56  and  58 . The ridgelines  70 ,  72 ,  74  and  76  align in a circular configuration, as shown in  FIG. 4 . The circular configuration is promoted by the wedging action from beveled lower end  52  of rounding piston  24  forcing the segment pairs  40  and  42  into such a shape. Since all the segment pairs are interconnected, as will be described, the compliant swage assembly  54  as a whole assumes a circular shape for the purpose of swaging at the pre-designated maximum dimension, illustrated in the perspective view of  FIG. 10 . 
     FIG. 4  shows a mode of interconnection. Every segment preferably has a tongue  78  on one edge and a groove  80  on the opposite edge. On either side of each tongue  78  are surfaces  82  and  84 . On either side of groove  80  are surfaces  86  and  88 . Surfaces  84  and  88  define a gap  90  between them and surfaces  82  and  86  define a gap  92  between them. These gaps allow articulation between adjacent segments so that the circular shape shown in  FIG. 4  for swaging at maximum dimension uniformly until an exterior obstruction is met can change into an out of round shape shown in  FIG. 7 . To assume the shape of  FIG. 7 , some of the gaps  90  have closed completely while gaps  92  between the same two segments have opened fully in zones  94  and  96 . At the same time, in zones  98  and  100  the movement is opposite. The compliant swage assembly  54  has now taken a somewhat oval shape in departing from the optimal round shape. It should be noted that depending on the allowable dimensions of gaps  90  and  92  a greater or lesser amount of articulation is possible. There are several limiting factors on the amount of articulation provided. One is the strength of the connection between a tongue  78  and an adjacent groove  80 . Another, is the desire to keep the outer gaps  92  to a minimum dimension for the reason that large gaps can allow opposed edges such as  102  and  104  to concentrate stress in the expanded tubular by putting line scores in it. Depending on the amount of expansion and subsequent service, such scoring and stress concentration can result in premature cracking of the expanded tubular.  FIGS. 4 and 7  illustrate that the articulated swage assembly  54  is held together at maximum dimension of  FIG. 4  or in an out of round articulated shape to allow the expansion of the tubular to the maximum dimension where no resistance is encountered while allowing inward articulation to clear the obstruction in the zone where it is encountered. The net result is a larger expanded cross-section of the tubular where the obstruction occurs than would have been possible with the prior design that simply transitioned from a larger circle to a sufficiently smaller circle to clear the exterior obstruction. Another limiting issue on the amount of articulation is the tubular being expanded. There are limits that the tubular can endure in differential expansion between its various zones to clear an obstruction. The design of  FIGS. 4 and 7  represent one solution to the need to hold the segments together while permitting articulation to achieve a desired swaging shape change. Clearly the tongue and groove connections hold the assembly of segments together as they are moved from the run in position of  FIG. 1  to the onset of swaging position shown in  FIG. 2  with pressure applied to passage  14 . 
     FIGS. 12 ,  13 ,  14  and  15  show an alternate design. The segments are no longer in pairs as shown in  FIG. 3 ; rather a segment  110  has a T-shaped connection  108  to be inserted into an opening  38  in swage anchor  32 . Abutting on either side is a segment  106  that is oppositely oriented and connected to swage  60 . The interface between the segments  106  and  110  is no longer a tongue and groove. Rather, each interface is a pair of arcuate surfaces  112  and  114  to allow the assembly articulate from the originally round shape shown in  FIG. 12  to an out of round shape shown in  FIG. 13  to clear an obstruction external to the tubular being expanded. The end connections of the segments  106  and  110  respectively to swage anchor  32  and swage  60  are made deliberately loose to permit relative movement between surfaces  112  and  114  to permit the articulation to the desired shape to avoid the obstruction exterior to the tubular being swaged. One notable difference is that there are no gaps in the periphery  116  where the swaging action is taking place regardless of the configuration of the segments in the round or out of round positions shown in  FIGS. 12 and 13 . Those skilled in the art will appreciate that band springs or equivalents can be used to limit the outward movement of the segments  106  and  110  as the interacting arcuate surfaces  112  and  114  do not provide such an outward travel stop. Even using the interface of  FIGS. 12 and 13 , the minimum and maximum dimensions of the compliant swage assembly  54  shown in  FIGS. 1 and 2  are still achieved by relative longitudinal movement between the segments oriented uphole and those that are oppositely oriented. The total number of segments is fewer in the  FIGS. 12 ,  13 ,  14  and  15  version but greater numbers of segments can also be used. For example, segment pairs as shown in  FIG. 3  can be used with the arcuate edge interfaces, within the scope of the invention. Conversely, as shown in  FIG. 14  the segment pairs of  FIG. 3  can be cut in half using larger segments that still employ an edge connection using a tongue and groove or another mechanically equivalent arrangement. 
   The method of using any of the above-described configurations can be seen by initially looking at  FIG. 1  for the run in position. At this time there is no pressure applied in passage  14  and the piston  64  and with it the swage  60  and the connected segments, such as  56  and  58  are in their lowermost position, simply due to their own weight. The compliant swage assembly  54  is in the  FIG. 11  position with ridgelines  70  and  72  out of alignment with ridgelines  74  and  76 . The compliant swage  54  is therefore in its minimum diameter position. Those skilled in the art will realize that the expansion can occur along the aligned ridge lines, as shown in  FIG. 10  or along a surface as opposed to a line contact shown in  FIG. 10 . The  FIG. 10  position is achieved by putting pressure from the surface in passage  14  to push swage  60  uphole and to force rounding piston  24  down on beveled surfaces  48  and  50 . This latter action puts the compliant swage in a round configuration illustrated in  FIG. 4  for the start of swaging. This position of the apparatus A is shown in  FIG. 2 . If used, the fixed swage  60  enters the tubing to be expanded first. If it will not pass, the apparatus A must be retrieved. Once it passes, the compliant swage assembly  54 , now in the  FIG. 10  position due to pressure in passage  14 , makes contact with the tubular to be expanded. The segments remain in the round position shown in  FIG. 4  as long as there is no external obstruction to expansion of the tubular, as is shown in  FIG. 5 . When a restriction or obstruction is reached, as shown in  FIG. 6 , the compliant swage assembly  54  will articulate to change dimension to try to pass the obstruction by getting smaller in the zone where the obstruction is found and swaging as large as possible where the obstruction is not present. This articulation occurs with pressure continuing to be applied in passage  14 . If the tongue  78  of one segment is engaged to a groove  80  in an adjacent segment, relative rotation about an axis defined by the tongue in groove connection permits the articulation as the size of gaps  90  and  92  between the affected segment pairs begins to change. In the abutting arcuate surfaces design shown in two positions in  FIGS. 12 and 13 , relative rotations along the arcuate surfaces  112  and  114  results in the desired articulation while presenting a continuous and uninterrupted surface or edge  116  for continued swaging despite an obstruction. In the end, if the compliant swage assembly  54  can actually pass through the obstruction, the resulting cross-sectional area of the expanded tubular is larger than it otherwise would have been if its circular cross-section had been maintained but its dimension reduced to the point where the obstruction could have been cleared. Clearly the larger the number of segments in the compliant swage assembly  54  the better its ability to articulate. However, the maximum round diameter of the compliant swage assembly  54  and the required strength of the segments to actually do the swaging required will have an effect on the number of segments to be employed. 
   Those skilled in the art will appreciate that surfaces  112  and  114  do not have to be singular arcs or have the same radius. They can be a series of surfaces and have different curvatures. The illustrated embodiment is illustrative of the inventive concept of articulation in combination with nearly continuous edge or surface contact. The alternative articulation concept is also illustrative of the ability to articulate but allowing some gaps in the swaging line or surface contact to accomplish the desired articulation. 
   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.