Communicating Through a Barrier in a Well

Abstract

A technique that is usable with a well includes communicating a ballistic wave from a first point in a well to a second point in the well without propagating the ballistic wave along a detonating cord. The first and second points are separated by at least one foot. The technique includes responding to the ballistic wave near the second point to activate a downhole tool.

1 . A method usable with a well, comprising:
 generating first command-encoded impulse stimuli in the well to cause the stimuli second command-encoded stimuli to emerge from a communication barrier in the well; and   responding to the second command-encoded stimuli to initiate an activator of a downhole tool.   
   
   
       2 . The method of  claim 1 , wherein the generating comprises generating a fluid hammer. 
   
   
       3 . The method of  claim 1 , wherein each impulse stimulus exceeds approximately 2.7 N·m. 
   
   
       4 . The method of  claim 1 , wherein impulse stimuli comprises pressure waves, each pressure wave having a magnitude exceeding 200 psi for a duration of less than approximately 500 ms. 
   
   
       5 . The method of  claim 1 , wherein generating comprises activating a ballistic-based impulse generator. 
   
   
       6 . The method of  claim 1 , wherein generating comprises generating the impulse in a fluid of the well. 
   
   
       7 . The method of  claim 1 , wherein generating comprises activating a ballistic device. 
   
   
       8 . The method of  claim 1 , wherein generating comprises generating the impulse at the surface of the well. 
   
   
       9 . The method of  claim 1 , wherein generating comprises generating the impulse downhole in the well. 
   
   
       10 . The method of  claim 1 , wherein the communication barrier comprises at least one of the following: a fluid, a screen, cement and a metal. 
   
   
       11 . The method of  claim 1 , wherein the responding comprises initiating the activator only if the second command-encoded stimuli corresponds to a predetermined time signature. 
   
   
       12 . The method of  claim 1 , wherein the responding comprises activating at least one of the following in response to the second command-encoded stimuli: a valve, a plug and a shifting sleeve. 
   
   
       13 . A system usable with a well, comprising:
 a transmitter to generate first command-encoded impulse stimuli in the well to cause second command-encoded stimuli to emerge from a communication barrier in the well; and   a receiver located downhole in the well to respond to the second command-encoded stimuli to initiate an activator of a downhole tool.   
   
   
       14 . The system of  claim 13 , wherein the generating comprises generating a fluid hammer. 
   
   
       15 . The system of  claim 13 , wherein each impulse stimulus exceeds approximately 2.7 N·m. 
   
   
       16 . The system of  claim 13 , wherein impulse stimuli comprises pressure waves, each pressure wave having a magnitude exceeding 200 psi for a duration of less than approximately 500 ms. 
   
   
       17 . The system of  claim 13 , wherein the responding comprises initiating the activator only if the second command-encoded stimuli corresponds to a predetermined time signature. 
   
   
       18 . A method usable with a well, comprising:
 communicating acoustic energy having most of its spectral energy at a frequency greater than 300 Hertz downhole into the well; and   in response to the communication, activating a downhole tool.   
   
   
       19 . The method of  claim 18 , further comprising:
 downhole in the well, comparing a signature of the acoustic energy to a predetermined signature to determine whether or not to activate the tool   
   
   
       20 . The method of  claim 18 , wherein the act of activating the tool comprises:
 activating one of a valve, a plug and a shifting sleeve.   
   
   
       21 . A method usable with a well, comprising:
 communicating a ballistic wave from a first point in the well to a second point in the well without propagating the ballistic wave along a detonating cord, the first and second points being separated by at least one foot; and   responding to the ballistic wave near the second point to actuate a downhole tool.   
   
   
       22 . The method of  claim 21 , wherein the downhole tool comprises a perforating gun. 
   
   
       23 . The method of  claim 21 , wherein the communicating comprises:
 communicating through a communication barrier.   
   
   
       24 . The method of  claim 23 , wherein the communication barrier comprises a casing joint. 
   
   
       25 . The method of  claim 21 , wherein the downhole tool comprises a casing conveyed perforating gun. 
   
   
       26 . The method of  claim 21 , further comprising:
 generating the ballistic wave in response to the propagation of a detonation wave along a detonating cord.   
   
   
       27 . A system usable with a well, comprising:
 a ballistic generator located at a first point in the well to generate a ballistic wave; and   a tool being located at a second point in the well to respond to the ballistic wave,   wherein the ballistic wave does not propagate along a detonating cord between the first and second points, and the first and second points are separated by at least one foot.   
   
   
       28 . The system of  claim 27 , wherein the tool comprises a perforating gun. 
   
   
       29 . The system of  claim 27 , wherein the communicating comprises:
 communicating through a communication barrier.   
   
   
       30 . The system of  claim 29 , wherein the communication barrier comprises a casing joint. 
   
   
       31 . The system of  claim 27 , wherein the tool comprises a casing conveyed perforating gun. 
   
   
       32 . The system of  claim 27 , further comprising:
 generating the ballistic wave in response to the propagation of a detonation wave along a detonating cord.