Apparatus and method for repairing failure spots on subterranean well tubulars using shock waves

Abstract

An apparatus and method are disclosed for the repair of failure spots, such as holes, crevices, and the like, along a first tubular section, such as casing section(s) in subterranean wells. The apparatus includes a housing made of a malleable material, such as steel, which is responsive to shock waves generated by an explosive material, such as a detonator cord, carried inside the housing. The explosive detonator cord is activated to generate shock waves within the housing to expand the malleable housing to conform to the wall holes, openings and failure spots in the casing. Thereafter, a head, selectively securable to the housing, is disengaged from the housing during retrieval of the head after activation of the detonator cord, to retrieve the head from the well and leave the malleable housing intact and across the failure spots.

1 ) An apparatus for introduction into a subterranean well on a conduit for the repair of failure spots along a first tubular section encased within said well, comprising: 
 (a) a malleable cylindrical housing means responsive to shock waves generated within said housing to outwardly and radially expand said housing across and into said failure spots;    (b) means within said housing to generate shock waves to initiate expansion of said housing; and    (c) actuation means for actuating said means to generate said shock waves.    
   
   
       2 ) The apparatus of  claim 1 , further comprising: a head element initially secured to one end of said housing and selectively disengagable there from subsequent to expansion of said housing, said head element having means for securing said conduit thereto for introduction, setting and retrieval of said head element within the well, whereby the expanded housing is retained within said well and the head is retrieved from within the well.  
   
   
       3 ) The apparatus of  claim 1  wherein the means within said housing to generate shock waves comprises an elongated section of detonator cord.  
   
   
       4 ) A method for the repair of failure spots within or along a first tubular section encased within said well, comprising the steps of: 
 (1) introducing into the well on a conduit an apparatus, comprising: 
 (a) a malleable cylindrical housing means responsive to shock waves generated within said housing to outwardly and radially expand said housing across and into said failure spots;  
 (b) means within said housing to generate shock waves to initiate expansion of said housing; and  
 (c) actuation means for actuating said means to generate said shock waves;  
   (2) positioning the apparatus in the well whereby the cylindrical housing means straddles the failure spots; and    (2) actuating the actuation means to cause said means within said housing to generate shock waves to initiate expansion of said housing, whereby said housing is expanded into and across said failure spots.    
   
   
       5 ) The method of  claim 4  wherein said apparatus further comprises a head element initially secured to one end of said housing and is selectively disengageable there from, and means for securement of said head element for introduction, setting and retrieval of said head element within the well; and further comprising the step of releasing the head element from the housing subsequent to generation of said shock waves and retrieving the head means from within the well.