Shaped-charge liner with precursor liner

Abstract

The present disclosure suggests a method to remove well bore fluid from the path of a shaped-charge jet in order to reduce the effect it has on the jet tip. This most preferred embodiment uses a precursor liner and a primary liner both pressed in the same housing. In the most preferred embodiment, the primary liner is similar or equivalent to a standard big hole shaped charge liner. The precursor liner is pressed into the apex end of the primary liner and upon detonation is intended to form an initial very fast moving precursor jet to open a path through the fluid of the well bore annulus for the following primary jet. In the preferred embodiment the precursor liner is made from different material, preferably a less dense material and/or a material having a higher sound speed, than the material forming the primary liner.

What is claimed is:  
     
         1 . A liner for a shaped-charge having two liner components, each component having a convex outer surface, a concave inner surface, an apex having a center, a mouth portion of the liner component opposite the apex of the liner component, and a skirt portion terminating in a circular skirt edge at the mouth portion of the liner component, the liner comprising: 
 a first component made of a first material and having an opening at the center of the apex of the first component;    a second component made of a second material wherein a portion of the second component is within the opening at the center of the apex of the first component;    wherein the first material and the second material comprise different materials.    
     
     
         2 . The liner of  claim 1 , wherein the first material has a greater density than the second material.  
     
     
         3 . The liner of  claim 1 , wherein the second material has a greater sound speed than the first material.  
     
     
         4 . The liner of  claim 1 , wherein the first material comprises a metal.  
     
     
         5 . The liner of  claim 1 , wherein the first material is selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, tin, tin alloy, lead, lead alloy, powdered metal, powdered metal within a polymeric base, and sintered metal.  
     
     
         6 . The liner of  claim 1 , wherein the second material is selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, tin, tin alloy, lead, lead alloy, powdered metal, powdered metal within a polymeric base, sintered metal, compacted explosive, hardened explosive.  
     
     
         7 . The liner of  claim 1 , wherein the second material is selected from the group consisting of aluminum, copper alloy, and powdered metal in a polymeric base.  
     
     
         8 . The liner of  claim 1  wherein: 
 the first material comprises copper alloy; and  
 the second material comprises aluminum.  
 
     
     
         9 . The liner of  claim 1 , wherein each of the first and second components has a liner angle and wherein the second component has a liner angle which is no more than about 15 degrees greater than the liner angle of the first component.  
     
     
         10 . The liner of  claim 9 , wherein the liner angle of the second component is within about 15 degrees of the liner angle of the first component.  
     
     
         11 . The liner of  claim 10 , wherein the liner angle of the second component is less than the liner angle of the first component.  
     
     
         12 . The liner of  claim 1 , wherein each of the first and second components has a liner height and wherein the liner height of the second component is no more than about the liner height of the first component.  
     
     
         13 . The liner of  claim 12 , wherein the liner height for the second component is less than about ⅔ of the liner height for the first component.  
     
     
         14 . The liner of  claim 13 , wherein the liner height for the second component is between about ⅓ and ⅔ of the liner height for the first component.  
     
     
         15 . The liner of  claim 12 , wherein the liner height for the second component is less than about ½ of the liner height for the first component.  
     
     
         16 . The liner of  claim 15 , wherein the liner height for the second component is between about ¼ and ½ of the liner height of the first component.  
     
     
         17 . The liner of  claim 1 , wherein the second component has an approximately conical shape.  
     
     
         18 . The liner of  claim 1 , wherein the approximate shape of the apex of the first component is selected from the group consisting of hemispherical, parabolic, ellipsoidal, flattened parabolic and hyperbolic and is radially symmetric about the central axis passing through the apex.  
     
     
         19 . The liner of  claim 1 , wherein 
 the circular skirt edge of the first component has a diameter;    the circular skirt edge of the second component has a diameter; and,    the ratio of the diameter of the circular skirt edge of the second component to the diameter of the circular skirt edge of the first component is between about 0.05 and about 0.35.    
     
     
         20 . The liner of  claim 19 , wherein the ratio of the diameter of the circular skirt edge of the second component to the diameter of the circular skirt edge of the first component is between about 0.10 and about 0.25.  
     
     
         21 . The liner of  claim 1 , wherein 
 the circular skirt edge of the second component has a diameter; and,    wherein the circular skirt edge of the second component has a diameter of between about 0.30 inches and about 0.45 inches.    
     
     
         22 . A method for making a shaped-charge, the method comprising 
 forming a first liner component of a first material wherein the first liner component has an apex and an opening at the center of the apex;    forming a second liner component of a second material wherein the second material is not identical to the first material;    providing a housing containing explosive material; and    assembling the first component and the second component into the housing acting together to line the explosive material wherein a portion of the second component is within the opening at the center of the apex of the first component.    
     
     
         23 . The method of  claim 22 , wherein the action of forming the first liner component comprises drawing the first liner component.  
     
     
         24 . The method of  claim 22 , wherein the action of forming the first liner component comprises molding the first liner component.  
     
     
         25 . The method of  claim 22 , wherein the action of forming the second liner component comprises drawing the second liner component.  
     
     
         26 . The method of  claim 22 , wherein the action of forming the second liner component comprises molding the second liner component.  
     
     
         27 . The method of  claim 22  wherein the first and second components are joined.  
     
     
         28 . The method of  claim 22  wherein the first and second components are joined before assembling the components into the housing.  
     
     
         29 . The method of  claim 22  wherein the first and second components are joined during assembly of the components into the housing.  
     
     
         30 . The method of  claim 27 , wherein the action of joining the first and second components comprises fitting a portion of the second component within the opening in the apex of the first component.  
     
     
         31 . The method of  claim 30 , wherein the action of fitting comprises pressing the second component into the opening of the apex of the first component until an interference fit is attained between the two components.  
     
     
         32 . The method of  claim 30 , wherein the second component has a mouth and a lip around the mouth and wherein the action of fitting comprises inserting the second component into the opening of the apex of the first component until the lip of the second component catches the edge of the opening of the first component.  
     
     
         33 . The method of  claim 32 , wherein the apex of the first component has a recess around the opening and wherein the lip of the second component fits into the recess around the opening of the first component.  
     
     
         34 . The method of  claim 30  further comprising the action of attaching the two components at the intersection of the opening of the apex and the portion of the second component.  
     
     
         35 . The method of  claim 34 , wherein the action of attaching comprises applying an adhesive coating.  
     
     
         36 . The method of  claim 34 , wherein the action of attaching comprises soldering.  
     
     
         37 . The method of  claim 34 , wherein the action of attaching comprises welding.