Apparatus and method for repair of underground conduits

Abstract

Apparatus and method for repairing underground conduits, such as well casings, particularly for repairing internal casings of deep wells. More particularly, the invention relates to a filter-sleeve and a method of conduit repair using such sleeve, without complete removal of the conduit or casing and without abandoning the well.

1 . A filter-sleeve for lining at least a portion of an underground conduit comprising: 
 a perforated core coiled around a longitudinal axis adapted to be expanded within the underground conduit at a site of repair; and    a filtering material surrounding the perforated core.    
   
   
       2 . A filter-sleeve according to  claim 1 , wherein the core comprises a rolled corrugated metal sheet.  
   
   
       3 . A filter-sleeve according to  claim 1 , wherein the core comprises a rolled plain metal sheet.  
   
   
       4 . A filter-sleeve according to  claim 1 , wherein the core comprises a rolled stainless steel sheet.  
   
   
       5 . A filter-sleeve according to  claim 1 , wherein the core comprises a coated steel or plastic sheet.  
   
   
       6 . A filter-sleeve according to  claim 1 , wherein the core is equipped with a locking device to facilitate locking of the core at the site of repair.  
   
   
       7 . A filter-sleeve according to  claim 1 , wherein the filtering material comprises felt, wire sieve, or a perforated sheet.  
   
   
       8 . A filter-sleeve according to  claim 1 , further comprising at least one O-ring surrounding the filtering material and for retaining the core in a coiled position for transporting the filter-sleeve to the site of repair.  
   
   
       9 . A filter-sleeve according to  claim 1 , further comprising an external protective material positioned over the filtering material.  
   
   
       10 . A filter-sleeve according to  claim 1  in combination with an expandable installation plug, wherein the filter-sleeve is coiled around the installation plug and is securely affixed to the installation plug.  
   
   
       11 . A combination filter-sleeve/plug combination of  claim 10 , further comprising a plurality of adhesive tapes, each of the tapes having a first portion attached to an end portion of the installation plug and to an inner surface of the filter-sleeve.  
   
   
       12 . A method of lining a host casing using the filter-sleeve according to  claim 1 , the method comprising: 
 coiling the core of the filter-sleeve on an inflatable installation plug to thereby produce a filter-sleeve/plug assembly;    inserting the filter-sleeve/plug assembly into an underground host casing and positioning the assembly at a location to be lined with the filter-sleeve;    expanding the inflatable installation plug to thereby expand the filter-sleeve and locking the filter-sleeve in place within the host casing.    
   
   
       13 . A method of lining a host casing according to  claim 12 , wherein the filter-sleeve includes O-ring(s), or other type of support device(s), surrounding the core for tightly fitting the filter-sleeve into the host casing and for supporting the filtering material.  
   
   
       14 . A method according to  claim 12 , further comprising deflating and removing the installation plug from the host casing.  
   
   
       15 . A method according to  claim 14 , wherein the filter-sleeve/plug assembly further comprises a plurality of adhesive tapes, each of the tapes having a first portion attached to an end portion of the installation plug, or to a portion of the assembly other than the filter-sleeve, and to an inner surface of the filter-sleeve, the method further comprising, after deflating the installation plug, raising the installation plug through the filter-sleeve and, during such raising, stripping the tapes from the inner surface of the filter-sleeve.