Sealed downhole equipment and method for fabricating the equipment

Abstract

A method and apparatus for preventing fluid flow and contamination to a cement body includes a resin cap covering an exposed end of the cement body. The cement body may attach an inner sleeve to an outer sleeve. The fluid flowing through the outer sleeve is prevented from contacting the exposed surface by the resin cap. Resin caps at both ends of the cement body along with resin layers along the side may be included. The resin prevents contamination and creation of micro-annuli in the cement body.

What is claimed is: 
     
         1 . A downhole tool for use in a casing string comprising:
 an outer sleeve adapted to be connected at first and second ends in the casing string;   an inner sleeve disposed in the outer sleeve;   a cement body disposed in an annular space defined by the inner and outer sleeves, the cement body having first and second ends and inner and outer surfaces; and   a resin cap at a first end of the cement body to prevent fluid flowing in the outer sleeve from contacting the cement body at the first end thereof.   
     
     
         2 . The downhole tool of  claim 1  comprising resin caps covering both of the first and second ends of the cement body. 
     
     
         3 . The downhole tool of  claim 1 , wherein the cement body affixes the outer sleeve to the inner sleeve. 
     
     
         4 . The downhole tool of  claim 1  further comprising a first layer of resin extending from the resin cap toward the second end of the cement body between an inner surface of the outer sleeve and an outer surface of the cement body. 
     
     
         5 . The downhole tool of  claim 4 , further comprising a second layer of bonding material extending from the resin cap toward the second end of the cement body between an outer surface of the inner sleeve and the inner surface of the cement body. 
     
     
         6 . The downhole tool of  claim 5 , further comprising a second resin cap at the second end of the cement body, wherein the first and second resin caps and the first and second layers of resin completely encapsulate the cement body. 
     
     
         7 . The downhole tool of  claim 1  further comprising a valve disposed in the outer sleeve, the outer sleeve comprising a float collar body, the inner sleeve comprising the valve housing of the valve. 
     
     
         8 . A downhole tool comprising:
 an outer sleeve defining a flow passage therethrough;   an inner sleeve defining a flow passage therethrough; and   a composite body disposed in an annulus defined by the inner and outer sleeve, the composite body comprising at least a combination of a cementitious material and a resinous material, wherein the composite body prevents fluid flow through the annulus and is bonded to the inner and outer sleeves.   
     
     
         9 . The downhole tool of  claim 8  wherein the inner sleeve comprises a landing collar. 
     
     
         10 . The downhole tool of  claim 8  further comprising a valve for permitting flow through the inner sleeve in one direction, wherein the inner sleeve comprises a valve housing. 
     
     
         11 . The downhole tool of  claim 10  comprising a float shoe. 
     
     
         12 . The downhole tool of  claim 10  comprising a float collar. 
     
     
         13 . A downhole tool for use in a casing comprising:
 an outer case adapted to be connected in the casing, the outer case defining a flow passage therethrough;   a check valve disposed in the outer case;   a cement body having first and second ends disposed in an annulus defined by the check valve and the outer case for blocking flow through the annulus; and   a first resin cap covering a first end of the cement body to prevent fluid in the outer case from contacting the first end of the cement body.   
     
     
         14 . The downhole tool of  claim 13 , further comprising a second resin cap at the second end of the cement body. 
     
     
         15 . The downhole tool of  claim 13  wherein the cement body affixes the outer case to a valve housing of the valve. 
     
     
         16 . The downhole tool of  claim 13  further comprising a first resin layer extending from the first resin cap toward the second end of the case between the cement body and the outer case. 
     
     
         17 . The downhole tool of  claim 16  further comprising a second resin layer extending from the first resin cap toward the second end of the case between the cement body and a valve housing at the valve. 
     
     
         18 . The downhole tool of  claim 17  further comprising a second resin cap covering the second end of the cement body, the first and second resin layer connecting the first and second resin caps so that the cement body is completely encapsulated.