Abstract:
Disclosed herein is a method for centralizing a downhole component. The method includes, delivering a tubular member with a plurality of lines of weakness therein to a site requiring a centralizer, and actuating the tubular member by causing a portion of the tubular member to deform radially from an unactuated position. The actuated portion contacting a downhole tubular structure, while maintaining at least two separate fluid passages. A first fluid passage between the portion of the tubular member and an outside surface of the tubular member in the unactuated position and a second fluid passage at a dimension smaller than that of the outside surface of the tubular member in the unactuated position.

Description:
BACKGROUND OF THE INVENTION 
   Some downhole operations, such as cutting a tubular structure, for example, can be improved by centering a tool within the tubular structure that carries out the operation. Cutters often have a plurality of knives, typically from two to five, that extend radially outwardly (or inwardly depending upon the specific application being cut) to engage the tubular structure being cut. The cutter rotates relative to the tubular structure being cut while the knives extend radially outwardly to thereby engage and cut through the wall of the tubular structure. If the cutter is not centered within the tubular structure the knives can contact and cut through a first portion of the tubular structure sooner than a second portion of the tubular structure that is, for example, diametrically opposite of the first portion. Such a cutting condition can cause excessive vibration, tool damage and an interrupted cut. 
   Consequently, centralizers are used to center the cutter relative to the tubular structure and thereby provide even engagement of the knives with walls of the tubular structures, which in turn results in a more even cut through the walls with less vibration. Centralizers often employ a plurality of flexible metal springs that engage the inside surface of the tubular structure to center the tool within the tubular structure. Such flexible metal springs however may have inadequate force to center a tool, for example when used in a nonvertically oriented tubular structure resulting in inadequate centering of the tool. Accordingly, there is a need in the art for a centralizer that can center tools regardless of biasing forces acting to urge the tools off center. 
   BRIEF DESCRIPTION OF THE INVENTION 
   Disclosed herein is a centralizer. The centralizer includes, a deformable tubular member having, a non-deformable portion with an outside surface defining a reference diameter, a deformable portion having an axis and being deformable to a greater radial dimension than the reference diameter. The greater radial dimension is contactable with a tubular structure within which the deformable tubular member is to be centralized. The deformable portion when in the deformed position has at least one first fluid passage with a greater radial distance from the axis than the reference diameter. The first fluid passage is fluidically isolated from at least one second fluidic passage at a radial dimension from the axis that is smaller than the reference diameter. Further, at least a portion of the deformable portion when deformed is in contact with the tubular structure so that the centralizer is centralized by such contact. The deformable tubular member further has a plurality of lines of weakness, at least one of which is at one of an inside surface and the outside surface and at least one other of the plurality of lines of weakness is at the other of the inside surface and the outside surface. The lines of weakness, upon axial loading of the centralizer cause deformation of the deformable portion and contact of the at least a portion of the deformable portion with the tubular structure. 
   Disclosed herein is a method for centralizing a downhole component. The method includes, delivering a tubular member with a plurality of lines of weakness therein to a site requiring a centralizer, and actuating the tubular member by causing a portion of the tubular member to deform radially from an unactuated position. The actuated portion contacting a downhole tubular structure, while maintaining at least two separate fluid passages. A first fluid passage between the portion of the tubular member and an outside surface of the tubular member in the unactuated position and a second fluid passage at a dimension smaller than that of the outside surface of the tubular member in the unactuated position. 
   Further disclosed herein is a method for making a centralizer. The method includes, configuring a deformable tubular member with a plurality of lines of weakness, at least one of the plurality of lines of weakness disposed at each of an inside dimension of the tubular member and an outside dimension of the tubular member. The method further includes, locating the plurality of lines of weakness relative to each other to facilitate deforming of the tubular member in a desired direction upon actuation. And configuring the centralizer tool such that at least a portion is contactable with a downhole structure to which the centralizer tool is centralizable after actuation of the centralizer tool. Additionally, forming at least two fluid passages isolated from one another, a first fluid passage being at a dimension greater than the outside dimension of the tubular member and a second fluid passage being at a dimension smaller than the outside dimension of the tubular member. 
   Further disclosed herein is a downhole centralizer system. The downhole centralizer system includes, a deformable tubular member with, a non-deformable portion having an outside surface defining a reference diameter, and a deformable portion having an axis and being deformable to a greater radial dimension than the reference diameter. The greater radial dimension is contactable with a tubular structure within which the deformable tubular member is to be centralized. The deformable portion when in the deformed position has a first fluid passage with a greater radial distance from the axis than the reference diameter and is fluidically isolated from a second fluid passage at a radial dimension from the axis that is smaller than the reference diameter. A portion of the deformable portion when deformed is in contact with the tubular structure so that the centralizer is centralized by such contact. The tubular member, also having a plurality of lines of weakness with at least one of the lines of weakness at an inside surface and at least one of the lines of weakness at the outside surface. Additionally, the lines of weakness, upon axial loading of the centralizer causing deformation of the deformable portion and contact of the portion of the deformable portion with the tubular structure. The system further having at least one additional operable component operably attached to the deformable tubular member, the component having operability facilitated by the deformable tubular member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
       FIG. 1  depicts a partial cross sectional view of a centralizer tool disclosed herein in an unactuated configuration; 
       FIG. 2  depicts a partial cross sectional view of the centralizer tool of  FIG. 1  in an actuated configuration; 
       FIG. 3  depicts a partial cross sectional view of the centralizer tool of  FIG. 2  taken at arrows  3 - 3 ; 
       FIG. 4  depicts a partial cross sectional view of another embodiment of a centralizer tool disclosed herein in an unactuated configuration; 
       FIG. 5  depicts a partial cross sectional view of the centralizer tool of  FIG. 4  in an actuated configuration; and 
       FIG. 6  depicts a partial cross sectional view of the centralizer tool of  FIG. 5  taken at arrows  6 - 6 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A detailed description of several embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
   Referring to  FIGS. 1 and 2 , a partial cross sectional view of an embodiment of the centralizer tool  10  is illustrated. The centralizer  10  includes a tubular member  14  and an actuatable centralizing portion  18 . As illustrated in  FIG. 1  the centralizing portion  18  is in an unactuated configuration and as illustrated in  FIG. 2  the centralizing portion  18  is in an actuated configuration. In the actuated configuration the centralizing portion  18  forms two frustoconical sections  22  and  26 . The greatest radial deformation  30  of the tubular member  14  occurs where the two frustoconical sections  22  and  26  meet. Thus, an annular flow area  34  is defined by the greatest radial deformation  30  and an outside surface  38  of the undeformed tubular member  14 . The greatest radial deformation  30  contacts an inner surface  42  of a tubular structure  46  within which the centralizer tool  10  is to be centralized and it is this contact that causes the centralizer tool  10  to become centralized within the tubular structure  46 . At least one axial groove  50  in the outside surface  38  forms a first fluid passage through which fluid can flow between an uphole annular area  54  and a downhole annular area  58  when the centralizer  10  is in the actuated configuration. A second fluid passage  52  is formed through the center of the tubular member  14  defined by the inside surface  62 . 
   Another operable component (not shown), such as a cutter, for example, can be can be attached to the centralizer tool  10 . The cutter can be located either uphole or downhole from the centralizer tool  10 , however, the cutter should be located close enough to the centralizer tool  10  that the cutter is centered within the tubular structure  46  by the centralization of the centralizer tool  10 . In so doing the centralizer tool  10  locates the cutter central to the tubular structure  46  such that the cutter engages the inner surface  42  substantially simultaneously to prevent detrimental vibrations and interrupted cuts. The centralizing force of the centralizer tool  10  can be controlled by the geometry and materials of the centralizer portion  18  such that noncentering loads encountered will not force the centralizer tool  10  off center. 
   The tubular member  14  is reconfigurable between the unactuated configuration and the actuated configuration. In the unactuated configuration the frustoconical sections  22  and  26  are configured as cylindrical components having roughly the same inside dimension as the tubular member  14  in the uphole annular area  54  and a downhole annular area  58 . Reconfiguration from the unactuated to the actuated configuration is effected, in one embodiment, by the application of an axial compressive load on the tubular member  14 . Similarly, reconfiguration from the actuated to the unactuated configuration is effected by the application of an axial tensile load on the tubular member  14 . 
   Reconfigurability of the tubular member  14  between the actuated configuration and the unactuated configuration is due to the construction thereof. The centralizer portion  18  is formed from a section of the tubular member  14  that has three lines of weakness, specifically located both axially of the tubular member  14  and with respect to an inside surface  62  and the outside surface  38  of the tubular member  14 . In one embodiment, a first line of weakness  66  and a second line of weakness  70  are defined in this embodiment by diametrical grooves formed in the outside surface  38  of the tubular member  14 . A third line of weakness  74  is defined in this embodiment by a diametrical groove formed in the inside surface  62  of the tubular member  14 . The three lines of weakness  66 ,  70  and  74  each encourage local deformation of the tubular member  14  in a radial direction that tends to cause the groove to close. It will be appreciated that in embodiments where the line of weakness is defined by other than a groove, the radial direction of movement will be the same but since there is no groove, there is no “close of the groove”. Rather, in such an embodiment, the material that defines a line of weakness will flow or otherwise allow radial movement in the direction indicated. The three lines of weakness  66 ,  70  and  74  together encourage deformation of the tubular member  14  in a manner that creates a feature such as the centralizer portion  18 . The feature is created, then, upon the application of an axially directed mechanical compression of the tubular member  14  such that the centralizer portion  18  is actuated as the tubular member  14  is compressed to a shorter overall length. Other mechanisms can alternatively be employed to actuate the tubular member  14  between the unactuated relatively cylindrical configuration and the actuated configuration presenting the frustoconical sections  22  and  26 . For example, the tubular member may be reconfigured to the actuated configuration by diametrically pressurizing the tubular member  14  about the inside surface  62  in the centralizer portion  18 . 
   Referring to  FIG. 3 , a cross sectional view of the centralizer tool  10  of  FIG. 2  is shown taken at arrows  3 - 3 . The fluid passages between the centralizer tool  10  and the inside surface  42 , of the tubular structure  46 , created by the axial grooves  50 , is illustrated. Although the axial grooves  50  are illustrated herein as V-shaped, it should be appreciated that alternate embodiments can have grooves of any shape. It should also be noted that in alternate embodiments the centralizer tool  10  could be used to center within an open bore  78  or any other tubular structure having a relatively consistent measurement to its axis. 
   Referring to  FIGS. 4 and 5 , an alternate exemplary embodiment of the centralizer tool  110  is illustrated. The centralizer  110  includes a tubular member  114  and an actuatable centralizing portion  118 . The centralizing portion  118  includes a plurality of extension members  120  attached thereto. As illustrated in  FIG. 4  the centralizing portion  118  is in an unactuated configuration and as illustrated in  FIG. 5  the centralizing portion  118  is in an actuated configuration. In the actuated configuration the centralizing portion  118  forms two frustoconical sections  122  and  126 . The extension members  120  are fixedly attached to the first frustoconical section  122  at a first portion  128 . A second portion  129  of the extension members  120  is positioned radially outwardly of the second frustoconical section  126  but is not attached to the second frustoconical section  126 . As such when the centralizing portion  118  is actuated the extension members  120  remain substantially parallel to the first frustoconical section  122  causing the second portion  129  of the extension members  120  to extend radially outwardly of the outermost portion of the frustoconical members  122 ,  126 . As such the greatest radial deformation  130  of the centralizer  110  is the end  132  of each of the extension members  120 . An annular flow area  134  is defined by the greatest radial deformation  130  and an outside surface  138  of the undeformed tubular member  114 . The greatest radial deformation  130  contacts an inner surface  42  of a tubular structure  46  within which the centralizer tool  110  is to be centralized and it is this contact that causes the centralizer tool  110  to become centralized within the tubular structure  46 . An axial space  150  between adjacent extension members  120  forms a first fluid passage through which fluid can flow between an uphole annular area  154  and a downhole annular area  158  when the centralizer  110  is in the actuated configuration. A second fluid passage  152  is formed through the center of the tubular member  114  defined by the inside surface  162 . 
   Another operable component (not shown), such as a cutter, for example, can be can be attached to the centralizer tool  110 . The cutter can be located either uphole or downhole from the centralizer tool  110 , however, the cutter should be located close enough to the centralizer tool  110  that the cutter is centered within the tubular structure  46  by the centralization of the centralizer tool  110 . In so doing the centralizer tool  110  locates the cutter central to the tubular structure  46  such that the cutter engages the inner surface  42  substantially simultaneously to prevent detrimental vibrations and interrupted cuts. The centralizing force of the centralizer tool  110  can be controlled by the geometry and materials of the centralizer portion  118  such that noncentering loads encountered will not force the centralizer tool  110  off center. 
   The tubular member  114  is reconfigurable between the unactuated configuration and the actuated configuration. In the unactuated configuration the frustoconical sections  122  and  126  are configured as cylindrical components having roughly the same inside dimension as the tubular member  114  in the uphole annular area  154  and a downhole annular area  158 . Reconfiguration from the unactuated to the actuated configuration is effected, in one embodiment, by the application of an axial compressive load on the tubular member  114 . Similarly, reconfiguration from the actuated to the unactuated configuration is effected by the application of an axial tensile load on the tubular member  114 . 
   Reconfigurability of the tubular member  114  between the actuated configuration and the unactuated configuration is due to the construction thereof. The centralizer portion  118  is formed from a section of the tubular member  114  that has three lines of weakness, specifically located both axially of the tubular member  114  and with respect to an inside surface  162  and the outside surface  138  of the tubular member  114 . In one embodiment, a first line of weakness  166  and a second line of weakness  170  are defined in this embodiment by diametrical grooves formed in the outside surface  138  of the tubular member  114 . A third line of weakness  174  is defined in this embodiment by a diametrical groove formed in the inside surface  162  of the tubular member  114 . The three lines of weakness  166 ,  170  and  174  each encourage local deformation of the tubular member  114  in a radial direction that tends to cause the groove to close. It will be appreciated that in embodiments where the line of weakness is defined by other than a groove, the radial direction of movement will be the same but since there is no groove, there is no “close of the groove”. Rather, in such an embodiment, the material that defines a line of weakness will flow or otherwise allow radial movement in the direction indicated. The three lines of weakness  166 ,  170  and  174  together encourage deformation of the tubular member  114  in a manner that creates a feature such as the centralizer portion  118 . The feature is created, then, upon the application of an axially directed mechanical compression of the tubular member  114  such that the centralizer portion  118  is actuated as the tubular member  114  is compressed to a shorter overall length. Other mechanisms can alternatively be employed to actuate the tubular member  114  between the unactuated relatively cylindrical configuration and the actuated configuration presenting the frustoconical sections  122  and  126 . For example, the tubular member  114  may be reconfigured to the actuated configuration by diametrically pressurizing the tubular member  114  about the inside surface  162  in the centralizer portion  118 . 
   Referring to  FIG. 6 , a cross sectional view of the centralizer tool  110  of  FIG. 5  is shown taken at arrows  6 - 6 . The fluid passages between the centralizer tool  110  and the inside surface  42 , of the tubular structure  46 , created by the axial spaces  150  between the extension members  120 , is illustrated. Although the extension members  120  depicted herein are rectangular prisms, it should be noted that alternate embodiments could have extension members of any shape. It should also be noted that in alternate embodiments the centralizer tool  110  could be used to center within an open bore  78  or any other substantially cylindrical structure. 
   While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.