Slim-line casing centralizer

Abstract

A casing centralizer having a multiplicity of support fingers positioned on a body of the casing centralizer each finger formed into a collapsible spring configured to support a predetermined load at an apex of the finger, each finger having a leading forward angle positioned downhole and a following aft angle positioned uphold and a landing tab positioned on an end of the finger adjacent the aft angle, the body includes a finger pocket which guides the landing tab with the finger collapses due to side loads.

What is claimed is: 
     
         1 . A casing centralizer having a multiplicity of support fingers positioned on a body of the casing centralizer, each support finger is formed into a collapsible spring configured to support a predetermined load at an apex of the support finger, each support finger having a leading forward angle positioned downhole and a following aft angle positioned uphole and a landing tab positioned at an end of the support finger adjacent the aft angle, the body having a finger pocket which guides the landing tab when the support finger collapses due to side loads. 
     
     
         2 . The centralizer of  claim 1  further comprising a stop collar positioned at opposite ends of the body. 
     
     
         3 . The centralizer of  claim 1  configured to be positioned around an outside diameter of a first casing and within an annular opening between the first casing and a larger diameter second casing. 
     
     
         4 . The centralizer of  claim 1  wherein the body is made of tempered steel, a low modulus high strength metal or fiber-epoxy composite. 
     
     
         5 . The centralizer of  claim 1  wherein the body is coated with a low friction material. 
     
     
         6 . The centralizer of  claim 5  wherein the low friction material includes urethane, ultra-high molecular weight polyethylene, Teflon® or PFA. 
     
     
         7 . The centralizer of  claim 1  wherein the support fingers are of different sizes. 
     
     
         8 . The centralizer of  claim 1  wherein the leading forward angle and the following aft angle range from about 15 to 85 degrees. 
     
     
         9 . The centralizer of  claim 8  wherein the leading forward angle and the following aft angle are different sizes. 
     
     
         10 . The centralizer of  claim 1  wherein the support fingers provide a variable amount of side load support. 
     
     
         11 . An apparatus for centralizing well bore casing comprising:
 a first casing extending within a bore hole of a well;   a second casing surrounding the first casing creating an annular space therebetween;   a casing centralizer positioned around the first casing in the annular space having a multiplicity of support fingers positioned on a body portion, each support finger formed into a collapsible spring configured to support a predetermined load at an apex of the support finger, each support finger having a leading forward angle position downhole and a following aft angle positioned uphold, the support fingers configured to collapse when exposed to the predetermined load; and   a stop collar is positioned at opposite ends of the body around the first casing.   
     
     
         12 . The apparatus of  claim 11  wherein the support fingers include a landing tab positioned on an end of each support finger adjacent the aft angle and wherein the body includes a finger pocket which guides the landing tab when the support finger collapses. 
     
     
         13 . The apparatus of  claim 11  wherein the casing centralizer is made of tempered steel, a low modulus high strength metal or fiber-epoxy composite. 
     
     
         14 . The apparatus of  claim 11  wherein the casing centralizer is coated with a low friction material. 
     
     
         15 . The apparatus of  claim 11  wherein the support fingers are of different sizes. 
     
     
         16 . The apparatus of  claim 11  wherein the support fingers are of an increasing height moving towards a center of the body portion. 
     
     
         17 . The apparatus of  claim 11  wherein the leading forward angle and the following aft angle range from about 15 to 85 degrees. 
     
     
         18 . The apparatus of  claim 17  wherein the leading forward angle and the following aft angle are different sizes. 
     
     
         19 . The apparatus of  claim 11  wherein the support fingers provide a variable amount of side load support. 
     
     
         20 . The apparatus of  claim 14  wherein the low friction material includes urethane, ultra-high molecular weight polyethylene, Teflon® or PFA.