Seismic Explosive System

Abstract

An explosive package is provided for use in seismic exploration which comprises a seismic charge and an addressable switch for selecting that seismic charge for detonation. A fireset is operatively coupled to the addressable switch for receiving a firing voltage via the addressable switch and for producing an actuation voltage. The actuation voltage may, for example be produced by increasing the magnitude of the firing voltage. The actuation voltage is provided to a Detonating Device, which is a device that contains secondary explosives. Examples of a Detonating Device include an exploding bridge wire detonator, an exploding foil initiator detonator and a semiconductor bridge slapper device. Such explosive packages may be arranged in a system for use in seismic exploration which comprises a base unit for providing selection, firing and trigger signals and a plurality of explosive packages that are located at spaced intervals along the earth's surface.

1 . An explosive package for use in seismic exploration that requires a first arming signal, a second arming signal, and a firing signal to be detonated, comprising:
 a seismic charge;   an addressable switch that receives the first arming signal and the second arming signal, the addressable switch being responsive to the first arming signal, the first arming signal being for use in selecting the seismic charge for detonation, the second arming signal being passed on to a fireset based on a response of the addressable switch to the first arming signal;   the fireset being responsive to the second arming signal and being operatively coupled to the addressable switch for receiving a firing signal via the addressable switch and for producing an actuation voltage at its output based on the firing signal; and   a Detonating Device which is operatively coupled to the output of the fireset for detonating the seismic charge upon presentation of the actuation voltage to the Detonating Device.   
     
     
         2 . The explosive package of  claim 1 , wherein the Detonating Device is selected from the group consisting of exploding bridge wire detonators, exploding foil initiator detonators and semiconductor bridge slapper detonators. 
     
     
         3 . The explosive package of  claim 1 , wherein the fireset comprises circuitry for increasing the magnitude of the firing signal to produce the actuation voltage. 
     
     
         4 . A system for use in seismic exploration, comprising:
 a plurality of explosive packages wherein each said explosive package requires a first arming signal, a second arming signal, and a firing signal to be detonated wherein each said package comprises:   a seismic charge;   an addressable switch which receives the first arming signal and the second arming signal, the addressable switch being responsive to the first arming signal and being operatively coupled to said seismic charge, the second arming signal being passed on to the fireset based on a response of the addressable switch to the first arming signal;   a fireset which is responsive to the second arming signal and which is operatively coupled to the addressable switch for receiving a firing signal via the addressable switch and for producing an actuation voltage at is output based on the firing signal; and   a Detonating Device which is operatively coupled to the output of the fireset for detonating the seismic charge upon presentation of the actuation voltage to the Detonating Device.   
     
     
         5 . The system of  claim 4 , wherein:
 the Detonating Device is selected from the group consisting of exploding bridge wire detonators, exploding foil initiator detonators, and semiconductor bridge slapper detonators.   
     
     
         6 . The system of  claim 4 , wherein:
 the fireset comprises circuitry for increasing the magnitude of the firing signal to produce the actuating voltage.   
     
     
         7 . A system for use in seismic exploration, comprising:
 a) a base unit comprising a computer and a power supply for providing selection signals, firing signals and trigger signals;   b) a plurality of explosive packages located at spaced locations along the earth's surface, which each explosive package requires a first arming signal, a second arming signal, and a firing signal to be detonated and wherein each explosive package comprises: (i) a seismic charge; (ii) an addressable switch which is responsive to the first arming signal, the addressable switch passing the second arming signal on to a fireset based on a response of the addressable switch to the first arming signal; (iii) the fireset which receives the second arming signal from the base unit via the selected addressable switch and which produces an actuation signal at its output; and (iv) a Detonating Device which is operatively coupled between the output of the fireset and the seismic charge for receiving the actuation signal and for detonating the seismic charge upon receipt of said actuation signal.   
     
     
         8 . The system of  claim 7 , wherein the Detonating Device is selected from the group consisting of exploding bridge wire detonators, exploding foil initiator detonators, and semiconductor bridge slapper detonators. 
     
     
         9 . (canceled) 
     
     
         10 . A method of detonating a particular one of a plurality of explosive packages where each said explosive packages includes a charge, comprising:
 (a) selecting the particular explosive package;   (b) providing a firing signal with an initial voltage to the selected explosive package, the initial voltage of the firing signal being insufficient to cause detonation of the charge in the selected explosive package; and   (c) increasing the amplitude of the firing signal to a level sufficient to detonate the charge in the selected explosive package.