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 . An apparatus for locating an annular recess along a wellbore string, comprising:
 a plurality of circumferentially-spaced, radially outwardly extending dogs for engaging the recess; and   a plurality of supporting structures for supporting the plurality of dogs;   
       wherein each supporting structure comprises:
 two or more radially stacked layers of circumferentially-spaced, radially flexible, leaf spring beam members extending along an axial direction. 
 
     
     
         2 . 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 or less than 60 degrees. 
     
     
         3 . The apparatus of  claim 2  wherein the first interface angle is about 50 degrees. 
     
     
         4 . The apparatus of  claim 2  wherein the first interface is an uphole interface. 
     
     
         5 . The apparatus of  claim 1  wherein at least a first layer of the two or more layers of circumferentially spaced leaf spring beam members form a locator cage. 
     
     
         6 . The apparatus of  claim 5  wherein the locator cage is a slotted tubular. 
     
     
         7 . The apparatus of  claim 5  wherein the circumferentially spaced leaf spring beam members of the locator cage are supported at one of two axially opposite ends thereof by a solid tubular portion. 
     
     
         8 . The apparatus of  claim 5  wherein the circumferentially spaced leaf spring beam members of the locator cage are supported at each of two axially opposite ends thereof by a solid tubular portion. 
     
     
         9 . The apparatus of  claim 5  wherein the at least first layer is the radially outmost layer, and wherein at least a second layer of the two or more layers of circumferentially spaced leaf spring beam members form a reinforcement cage. 
     
     
         10 . The apparatus of  claim 9  wherein the reinforcement cage is a slotted tubular. 
     
     
         11 . The apparatus of  claim 9  wherein the circumferentially spaced leaf spring beam members of the locator cage are supported at one of two axially opposite ends thereof by a solid tubular portion. 
     
     
         12 . The apparatus of  claim 9  wherein the circumferentially spaced leaf spring beam members of the locator cage are supported at each of two axially opposite ends thereof by a solid tubular portion. 
     
     
         13 . The apparatus of  claim 9  wherein the reinforcement cage is concentrically received in the locator cage. 
     
     
         14 . The apparatus of  claim 9  wherein each dog is supported by at least one beam member of the first layer, and each beam member of the first layer is supported by at least one beam member of the at least second layer. 
     
     
         15 . The apparatus of  claim 9  wherein the locator cage further comprises a first coupling mechanism at an uphole end thereof for coupling the locator cage to a first sub and a second coupling mechanism at a downhole end thereof for coupling the locator cage to a second sub. 
     
     
         16 . The apparatus of  claim 15  wherein, after the locator cage is coupled to a first sub at the uphole end thereof and to a second sub at the downhole thereof, the at least first reinforcement cage is axially fixed or axially moveable within a predefined range. 
     
     
         17 . The apparatus of  claim 9  wherein the reinforcement cage is circumferentially fixed with respect to the locator cage. 
     
     
         18 . The apparatus of  claim 17  further comprising:
 a delimit pin extending from the reinforcement cage radially outwardly into a slot between two adjacent positioned in a slot between two adjacent spring beam members of the locator cage, for preventing the reinforcement cage from rotating with respect to the locator cage. 
 
     
     
         19 . The apparatus of  claim 1  wherein the two or more radially stacked layers of leaf spring beam members are radially aligned. 
     
     
         20 . An apparatus for locating an annular recess along a wellbore string, comprising:
 a tubular locator cage having a plurality of circumferentially-spaced, radially flexible, locator leaf spring beam members extending along an axial direction, each locator leaf spring beam member having a locator dog thereon and extending radially outwardly, the locator cage having a locator bore; and   at least a first tubular reinforcement cage fit concentrically within the locator bore, each of the at least a first tubular reinforcement cage having a plurality of circumferentially-spaced, radially flexible, reinforcement spring beam members extending along the axial direction and for supporting the locator leaf spring beam members.