Detonator output interrupter for downhole tools

Abstract

An apparatus for selectively activating a downhole tool by using a shockwave generated by a detonator assembly may include an outer housing having a bore and an inner housing disposed in the bore of the outer housing. The inner housing may include a chamber having at least one canted surface, an inlet communicating with the chamber and being positioned between the chamber and the detonator assembly, an outlet communicating with the chamber and being positioned between the chamber and the downhole tool, and an energy blocker disposed in the chamber and being freely movable in the chamber as the inner housing changes orientation relative to a vertical datum. The energy blocker axially aligns with the inlet and the outlet when the inner housing is angularly offset less than a specified amount relative to a vertical datum.

What is claimed is: 
     
         1 . An apparatus for selectively activating a downhole tool in a wellbore by using a shockwave generated by a detonator assembly, comprising:
 an outer housing having a bore;   an inner housing disposed in the bore of the outer housing, the inner housing including:
 a chamber having at least one canted surface; 
 an inlet communicating with the chamber, the inlet positioned between the chamber and the detonator assembly, 
 an outlet communicating with the chamber, the outlet positioned between the chamber and the downhole tool; and 
 an energy blocker disposed in the chamber, the energy blocker being freely movable in the chamber as the inner housing changes orientation relative to a vertical datum, the energy blocker axially aligning with the inlet and the outlet when the inner housing is angularly offset less than a specified amount relative to the vertical datum. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the energy blocker is a spherical body. 
     
     
         3 . The apparatus of  claim 1 , wherein the outer housing and the inner housing are cylindrical and the at least one surface has a conical shape. 
     
     
         4 . The apparatus of  claim 1 , wherein the at least one canted surface is canted toward one of: (i) the inlet, and (ii) the outlet. 
     
     
         5 . The apparatus of  claim 1 , wherein the chamber includes opposing surfaces that are substantially transverse to the vertical datum, wherein the at least one canted surface is formed on one of the opposing surfaces. 
     
     
         6 . The apparatus of  claim 1 , wherein the chamber includes canted opposing surfaces that are substantially transverse to the vertical datum. 
     
     
         7 . The apparatus of  claim 1 , wherein the energy blocker is formed of at least one of: (i) steel, (ii) metal, (iii) ceramic, (iv) plastic, and (iv) a composite. 
     
     
         8 . An apparatus for use in a wellbore, comprising:
 a detonator assembly having a firing head and an initiator, the detonator assembly being configured to generate a shock wave when activated;   detonator output interrupter connectable with the detonator assembly, the detonator output interrupter having:
 an outer housing having a bore; 
 an inner housing disposed in the bore of the outer housing, the inner housing including:
 a chamber having a first and a second opposing surface, each opposing surface being substantially transverse to a vertical datum, wherein at least one of the first and the second opposing surfaces is canted; 
 an inlet communicating with the chamber, the inlet positioned between the chamber and the detonator assembly and having an end terminating at the first opposing surface, 
 an outlet communicating with the chamber and having an end terminating at the second opposing face, and 
 an energy blocker disposed in the chamber, the energy blocker being freely movable in the chamber as the inner housing changes orientation relative to a vertical datum, the energy blocker blocking the generated shock wave by axially aligning with the inlet and the outlet when the inner housing is angularly offset less than a specified amount relative to the vertical datum; and 
 
 a downhole tool connectable with the detonator output interrupter, the downhole tool being activated by a generated shock wave that is not blocked by the energy blocker. 
   
     
     
         9 . The apparatus of  claim 8 , wherein: the energy blocker is a spherical body, the outer housing and the inner housing are cylindrical, and a conical shape defines at least one of the (i) first opposing surface, and (ii) the second opposing. 
     
     
         10 . The apparatus of  claim 8 , wherein at least one of: (i) the first opposing surface is canted to the inlet, and (ii) the second opposing surface is canted toward the outlet. 
     
     
         11 . The apparatus of  claim 8 , wherein the first opposing surface is canted to the inlet and the second opposing surface is canted toward the outlet. 
     
     
         12 . The apparatus of  claim 8 , wherein the energy blocker is formed of at least one of: (i) steel, (ii) metal, (iii) ceramic, (iv) plastic, and (iv) a composite. 
     
     
         13 . The apparatus of  claim 8 , wherein the downhole tool includes a bi-directional booster charge and a detonating cord.