Rolled tubular centralizer

Abstract

A method of forming a centralizer where a flat plate is created into a tubular where the flat plate is typically rolled so that two sides of the plate contact one another and are then linked, typically by welding. Openings are then created in the tubular such that there are no corners or other points that stress cracks may originate. Once the openings are created the remaining material between adjacent openings forms ribs. The openings created in the tubular are generally aligned with the long axis of the tubular. The material at the upper and lower end of the flat plate where openings were not created serve as circumferential collars. The ribs may be radially outwardly expanded in order to provide adequate stand-off. In many instances the ribs will also be hardened by heat treating or other hardening processes.

What is claimed is: 
     
         1 . A method for manufacturing a centralizer, comprising:
 rolling a plate such that first and second sides of the plate are adjacent;   attaching together the first and second sides, such that a seam is formed where the first and second sides are attached together; and   after rolling the plate, removing one or more portions from the plate, such that two or more ribs are defined extending between two or more end collars.   
     
     
         2 . The method of  claim 1 , wherein removing the one or more portions of the plate occurs after attaching together the first and second sides. 
     
     
         3 . The method of  claim 1 , wherein removing the one or more portions comprises removing at least a portion of the seam. 
     
     
         4 . The method of  claim 1 , wherein removing the one or more portions comprises forming one or more openings that do not intersect the seam. 
     
     
         5 . The method of  claim 1 , wherein removing the one or more portions comprises forming one or more openings that extend substantially parallel to the seam. 
     
     
         6 . The method of  claim 5 , wherein the seam is defined along one of the two or more ribs. 
     
     
         7 . The method of  claim 1 , wherein removing the one or more portions comprises forming two or more openings between which the two or more ribs are defined, the two or more openings being substantially oval-shaped. 
     
     
         8 . The method of  claim 1 , wherein the seam comprises a non-linear shape selected from the group consisting of: one or more smooth curves, one or more jagged curves, or one or more zig-zag shapes. 
     
     
         9 . The method of  claim 1 , wherein attaching together the first and second sides comprises welding the first and second sides together, without overlapping. 
     
     
         10 . The method of  claim 1 , wherein:
 rolling the plate comprises spiral winding the plate;   the seam extends along a helical path; and   removing the one or more portions comprises forming one or more openings that intersect the seam at least once.   
     
     
         11 . The method of  claim 1 , wherein:
 the plate comprises a first plate segment and a second plate segment, the first plate segment providing the first side and the second plate segment providing the second side; and   rolling the plate comprises forming each of the first and second plate segments into an arcuate shape.   
     
     
         12 . A centralizer, comprising:
 a tubular body comprising a first side and a second side, the first and second sides extending axially along the tubular body, wherein the tubular body defines at least first and second axially-offset end collars and a plurality of ribs extending between the first and second end collars, the plurality of ribs being integral with the first and second end collars; and   a seam connecting the first side and the second side together, wherein the seam is formed along at least a portion of the first end collar and along at least a portion of the second end collar, such that the first and second sides are connected together to form the first and second end collars without overlapping the first and second sides.   
     
     
         13 . The centralizer of  claim 12 , wherein the seam is circumferentially aligned with an opening defined between two of the plurality of ribs. 
     
     
         14 . The centralizer of  claim 12 , wherein the seam extends parallel to and along an entirety of at least one of the plurality of ribs. 
     
     
         15 . The centralizer of  claim 12 , wherein the plurality of ribs are elongated in an axial direction, and wherein the seam extends at a non-zero angle to the axial direction and is defined on at least one of the plurality of ribs. 
     
     
         16 . The centralizer of  claim 15 , wherein the seam is defined on at least two of the plurality of ribs. 
     
     
         17 . The centralizer of  claim 15 , wherein the seam extends in a partial helix along the body. 
     
     
         18 . The centralizer of  claim 12 , wherein the first and second sides each define one or more curves. 
     
     
         19 . The centralizer of  claim 12 , wherein the first and second sides are connected end-to-end without overlap. 
     
     
         20 . The centralizer of  claim 12 , wherein the tubular body further comprises third and fourth sides, and the centralizer further comprises a second seam connecting together the third and fourth sides. 
     
     
         21 . A centralizer, comprising:
 a first end collar comprising a first seam portion extending axially across the first end collar;   a second end collar that is axially offset from the first end collar and comprises a second seam portion extending axially across the second end collar; and   a plurality of ribs extending between the first and second end collars and being integral therewith, at least one of the plurality of ribs comprising a third seam portion.   
     
     
         22 . The centralizer of  claim 21 , wherein the first end collar and the second end collar are free from overlapping regions. 
     
     
         23 . The centralizer of  claim 21 , wherein the first and second seam portions are circumferentially aligned. 
     
     
         24 . The centralizer of  claim 21 , wherein the first, second, and third seam portions form a continuous seam. 
     
     
         25 . The centralizer of  claim 21 , wherein the plurality of ribs are elongated in an axial direction, and wherein the third seam portion extends at a non-zero angle with respect to the axial direction. 
     
     
         26 . The centralizer of  claim 25 , wherein the first, second, and third seam portions together extend along a helical path. 
     
     
         27 . The centralizer of  claim 21 , wherein at least two of the plurality of ribs define the third seam portion. 
     
     
         28 . A method for manufacturing a centralizer, comprising:
 rolling a substantially linear plate such that first and second sides of the plate are adjacent;   attaching together the first and second sides, such that a first seam portion, a second seam portion and a third seam portion are formed; and   removing one or more portions from the plate, such that two or more ribs are defined extending between two end collars.   
     
     
         29 . The method of  claim 28 , wherein the first, second, and third seam portions form a continuous seam 
     
     
         30 . The method of  claim 28 , wherein the two end collars include the first and second seam portions, respectively.