Compound beam mechanical casing collar locator

Abstract

A mechanical casing collar locator is disclosed. The casing collar locator has an outermost, locator leaf spring cage, and one or more radially stacked reinforcement leaf spring cages. Each leaf spring cage has a plurality of flexible leaf spring beam members, each having a locator dog thereon for engage collar recesses, or other recesses, in the wellbore casing. The leaf spring beam members of the reinforcement leaf spring cages radially support the leaf spring beam members and the locator dogs of the locator leaf spring cage for providing enhanced radially outward spring force.

What is claimed is: 
     
         1 . Apparatus for coupling with a downhole tool, the apparatus releasably locating an annular recess along a casing string in a wellbore, comprising:
 a tubular locator cage, adapted for coupling to the downhole tool, having
 a tubular housing having opposing ends, 
 a locator bore, and 
 a plurality of radially flexible locator leaf spring beam members extending along an axial direction from each opposing end and spaced circumferentially from each other by locator slots, each locator slot terminating axially inward of the housing's opposing ends, each locator leaf spring beam member having a locator dog extending radially outwardly therefrom and intermediate therealong for engaging the annular recess; 
   at least a first tubular reinforcement cage fit concentrically within the locator bore, each reinforcement cage having
 a plurality of radially flexible reinforcement spring beam members extending along the axial direction, spaced circumferentially from each other by slots, wherein 
   each reinforcement cage being retained in the locator bore in axial arrangement wherein that each locator leaf spring beam member is supported by at least one reinforcement beam member for providing an aggregated radial spring force at the locator dogs.   
     
     
         2 . The apparatus of  claims 1  further comprising:
 an uphole sub connected to an uphole end of the locator cage; and 
 a downhole sub connected to a downhole end of the locator cage. 
 
     
     
         3 . The apparatus of  claim 1  wherein each reinforcement cage is delimited within the locator bore in axial arrangement between the uphole sub and the downhole sub. 
     
     
         4 . The apparatus of  claim 1  wherein each reinforcement cage has a tubular housing having opposing ends and a bore. 
     
     
         5 . The apparatus of  claim 4  wherein at least a second reinforcement cage is fit concentrically within the bore of the first reinforcement cage and in axial arrangement therewith. 
     
     
         6 . The apparatus of  claim 1  wherein each reinforcement cage has an axial length shorter than the axial length of the locator cage wherein the reinforcement cage's opposing ends are exposed through the locator slots for securing a delimit pin therethrough and maintaining circumferential arrangement of the spring beam members of the locator cage and each reinforcement cage. 
     
     
         7 . The apparatus of  claim 1  wherein each dog comprises a first interface for engaging an edge of the recess, the first interface being angled from the axial direction at a first interface angle of about 60 degrees to about 15 degrees. 
     
     
         8 . The apparatus of  claim 7  wherein the first interface angle is about 50 degrees. 
     
     
         9 . The apparatus of  claim 7  wherein the first interface is an uphole interface. 
     
     
         10 . The apparatus of  claim 1  wherein the circumferentially spaced leaf spring beam members of the locator cage are supported a solid tubular portion of the housing's opposing ends. 
     
     
         11 . The apparatus of  claim 1  wherein the reinforcement cage is circumferentially fixed with respect to the locator cage. 
     
     
         12 . The apparatus of  claim 11  further comprising:
 a delimit pin extending from the reinforcement cage radially outwardly into the locator slot, for preventing the reinforcement cage from rotating with respect to the locator cage. 
 
     
     
         13 . The apparatus of  claim 1  wherein the leaf spring beam members of the locator cage and each reinforcement cage are radially aligned. 
     
     
         14 . The apparatus of  claim 1  wherein a radially outwardly directed spring force of the locator dogs comprises an aggregated radial spring force exerted by stacked leaf spring beam members of the locator cage and each reinforcement cage. 
     
     
         15 . The apparatus of  claim 14  wherein the dogs drag along the casing string when not located in the annular recess. 
     
     
         16 . Apparatus conveyed downhole for releasably locating an annular recess along a casing string in a wellbore comprising:
 an uphole sub and a downhole sub;   a tubular beam locator cage having a locator bore, opposing uphole and downhole ends, and a plurality of radially flexible, leaf spring locator beam members, extending axially between each opposing end, and spaced circumferentially from each other by locator slots, each locator slot terminating axially inward of the housing's opposing ends, each locator leaf spring beam member having a locator dog extending radially outwardly therefrom and intermediate therealong and adapted for engaging the annular recess, the uphole end of the locator cage connected to the uphole sub, and the downhole end of the locator cage being connected to the downhole sub; and   at least a first tubular reinforcement cage fit concentrically within the locator bore and axially delimited and sandwiched to float axially between the uphole and downhole subs, each reinforcement cage having a plurality of radially flexible spring reinforcement beam members extending along the axial direction, spaced circumferentially from each other by slots, wherein each locator beam member is supported by at least one reinforcement beam member for providing an aggregated radial spring force at the locator dogs.   
     
     
         17 . Apparatus conveyed downhole for releasably locating an annular recess along a casing string in a wellbore comprising:
 an uphole sub and a downhole sub;   a tubular beam locator cage of locator beams connected at an uphole end to the uphole sub and a downhole end connected to the downhole sub, a recess locator dog extending radially outwardly intermediate along the locator cage,   at least a first tubular reinforcement cage of reinforcing beams fit concentrically to, and delimited axially, within the locator cage wherein each locator beam is supported radially by a reinforcement beam of the at least one reinforcement cage for providing an aggregated radial spring force at the recess locator dogs, wherein   wherein upon radial displacement of the locator beam loading an axial spacing of the uphole and downhole subs changes and axial length of the reinforcement cage is unconstrained