Method and apparatus for repair of wells utilizing meltable repair materials and exothermic reactants as heating agents

Abstract

A method and apparatus are described for creating a fluid seal in a subterranean well structure having a fluid seal defect. The method comprises introducing a meltable repair material proximate a structure in a subterranean well which has a fluid seal defect or enhanced seal capacity is required or it is desired to temporarily or permanently hydraulically isolate a portion the well or strengthen the structural integrity of well tubulars or tubular hangers. Exothermic reactant materials are located proximate the meltable repair material. The exothermic reactant material is ignited or an exothermic reaction otherwise initiated which supplies heat to and melts the meltable repair material into a molten mass. The molten mass flows and solidifies across the structure and the fluid seal defect to effect a fluid seal in the subterranean well structure or the structural integrity is enhanced. Examples of preferred exothermic reactant materials include thermite, thermate, fusible chemical reactants such as ammonium chloride and sodium nitrate, and oxidizers and accompanying hydrocarbon based fuels. Examples of preferred meltable repair materials include solder or brazing materials and eutectic metals which expand upon cooling and solidifying from a molten state.

1 . A method for creating a fluid seal in a subterranean well structure having a fluid seal defect, the method comprising: 
 introducing a meltable repair material proximate a structure in a subterranean well which has a fluid seal defect or an isolating plug is desired;    introducing exothermic reactant materials proximate the meltable repair material;    igniting the exothermic reactant materials or otherwise initiating the exothermic reaction which supplies heat to and melts the meltable repair material into a molten mass;    flowing the molten mass to contact the structure and fluid seal defect; and    allowing the molten mass to solidify across the structure and the fluid seal defect to effect a fluid seal in the subterranean well structure.    
   
   
       2 . The method of  claim 1  wherein: 
 the exothermic reactant material includes thermite.    
   
   
       3 . The method of  claim 1  wherein: 
 the exothermic reactant material includes thermate.    
   
   
       4 . The method of  claim 1  wherein: 
 the exothermic reactant material includes bromine trifluoride.    
   
   
       5 . The method of  claim 1  wherein: 
 the exothermic reactant includes a fused chemical reaction.    
   
   
       6 . The method of  claim 5  wherein: 
 the fused chemical reaction includes using ammonium chloride and sodium nitrate as the exothermic reactant material and an acid catalyst acts as an igniter to initiate the exothermic reaction.    
   
   
       7 . The method of  claim 1  wherein: 
 the subterranean well structure which is repaired includes one of leaking cemented annuli or tubing packer or weak tubing hanger, leaking or potentially leaking plugs including cement and mechanical plugs, abandoned and unwanted perforations, high pressure intervals which are to be temporarily or permanently isolated, and gravel-packed production intervals which are to be shut-off from water influx.    
   
   
       8 . The method of  claim 1  wherein: 
 the meltable repair material is a solder.    
   
   
       9 . The method of  claim 1  wherein: 
 the meltable repair material is a eutectic metal.    
   
   
       10 . The method of  claim 1  wherein: 
 the meltable repair material is a eutectic metal which expands upon cooling and solidifying.    
   
   
       11 . The method of  claim 1  wherein: 
 the meltable repair material and the exothermic material are introduced within a single repair tool.    
   
   
       12 . The method of  claim 1  wherein; 
 the meltable repair material and the exothermic material are introduced sequentially proximate the structure to be repaired.    
   
   
       13 . A repair tool for effecting a fluid seal in a subterranean well structure having a fluid seal defect, the repair tool comprising: 
 a housing containing a meltable repair material and an exothermic reactant material proximate the meltable repair material;    wherein the housing may be introduced into a well and proximate a structure having a fluid seal defect and the exothermic reactant material may be ignited to melt the meltable repair material into a flowable molten mass which can be discharged from the housing to cool and solidify upon the structure to effect a fluid seal.    
   
   
       14 . The repair tool of  claim 13  wherein: 
 the meltable repair material includes at least one of a eutectic metal, a solder, a brazing material and a flux material to promote or increase adhesion.    
   
   
       15 . The repair tool of  claim 13  wherein: 
 the meltable repair material is eutectic metal which expands upon cooling and solidifiying from a molten state.    
   
   
       16 . The repair tool of  claim 13  wherein: 
 the exothermic reactant material is thermite.    
   
   
       17 . The repair tool of  claim 13  wherein: 
 the exothermic reactant material is thermate.    
   
   
       18 . The repair tool of  claim 13  wherein: 
 the exothermic reactant material includes ammonium chloride and sodium nitrite.    
   
   
       19 . The repair tool of  claim 13  wherein: 
 the housing includes a dump bailer and petal basket.    
   
   
       20 . The repair tool of  claim 13  further comprising: 
 an igniter to ignite the exothermic reactant material.    
   
   
       21 . The repair tool of  claim 13  wherein: 
 the exothermic reactant material includes an oxidizing agent and the repair meltable material includes a meltable metal and a hydrocarbon-based fuel;    wherein the oxidizing agent and the hydrocarbon-based fuel may be combined and ignited to melt the meltable metal.