Modular propellant assembly for fracturing wells

Abstract

A modular propellant assembly for fracturing wells has a propellant charge with a detonating cord extending along its length to ignite the propellant. Each propellant module also has end caps with male and female connectors that enable propellant modules to be connected in an end-to-end relationship to any desired length. These connectors align the ends of the detonating cords in adjacent propellant modules and are sealed with O-rings so that the detonating cords remains dry while submerged at high pressures. This enables the detonating cords to be ignited in series.

We claim:  
     
         1 . A modular propellant assembly for fracturing wells comprising: 
 a propellant charge;    a detonating cord extending along the propellant charge and having an upper end and a lower end;    an upper end connector for engaging a complementary end connector on an adjacent propellant module to align and seal the upper end of the detonating cord with the lower end of the detonating cord of an adjacent propellant module; and    a lower end connector for engaging a complementary end connector on an adjacent propellant module to align and seal the lower end of the detonating cord with the upper end of the detonating cord of an adjacent propellant module.    
     
     
         2 . The modular propellant assembly of  claim 1  further comprising a carrier containing the propellant charge and having perforations allowing combustion gases to escape from the propellant charge.  
     
     
         3 . The modular propellant assembly of  claim 1  further comprising a tube containing the detonating cord.  
     
     
         4 . The modular propellant assembly of  claim 1  further comprising a rod extending between the upper end connector and the lower end connector.  
     
     
         5 . The modular propellant assembly of  claim 1  further comprising a booster adjacent to an end of the detonating cord to ignite the detonating cord.  
     
     
         6 . The modular propellant assembly of  claim 1  wherein the propellant charge further comprises a groove holding the detonating cord.  
     
     
         7 . The modular propellant assembly of  claim 1  wherein one of the end connectors is a male connector and the other end connector is a complementary female connector.  
     
     
         8 . The modular propellant assembly of  claim 7  further comprising an O-ring creating a seal between the male and female connectors.  
     
     
         9 . A modular propellant assembly for fracturing wells comprising: 
 a propellant charge;    a tube extending along the propellant charge and having opposing ends;    a detonating cord within the tube; and    end connectors for engaging complementary end connectors on adjacent propellant modules and for aligning and sealing the ends of the tube with the ends of the tubes of adjacent propellant modules, so that the detonating cords of each propellant module can be ignited in series.    
     
     
         10 . The modular propellant assembly of  claim 9  further comprising a carrier containing the propellant charge and having perforations allowing combustion gases to escape from the propellant charge.  
     
     
         11 . The modular propellant assembly of  claim 9  further comprising a rod extending between the end connectors.  
     
     
         12 . The modular propellant assembly of  claim 9  further comprising a booster adjacent to an end of the detonating cord within the tube to ignite the detonating cord.  
     
     
         13 . The modular propellant assembly of  claim 9  wherein one of the end connectors is a male connector, and the other of the end connectors is a complementary female connector.  
     
     
         14 . The modular propellant assembly of  claim 13  further comprising an O-ring creating a seal between the male and female connectors.  
     
     
         15 . The modular propellant assembly of  claim 9  wherein the propellant charge further comprises a groove holding the tube and detonating cord.  
     
     
         16 . A modular propellant assembly for fracturing wells comprising: 
 a propellant charge;    a carrier containing the propellant charge and having upper and lower ends, and perforations allowing combustion gases to escape from the propellant charge;    a tube extending along the propellant charge inside the carrier;    a detonating cord within the tube; and    end connectors at the ends of the carrier for engaging complementary end connectors on adjacent propellant modules in an end-to-end relationship, wherein one of the end connectors is a male connector and the other end connector is a female connector, with both end connectors having openings for aligning and sealing the ends of the tube with the ends of the tubes of adjacent propellant modules, so that the detonating cords of each propellant module can be ignited in series.    
     
     
         17 . The modular propellant assembly of  claim 16  wherein the propellant charge further comprises a groove holding the tube and detonating cord.  
     
     
         18 . The modular propellant assembly of  claim 16  further comprising an O-ring creating a seal between the male and female connectors.  
     
     
         19 . The modular propellant assembly of  claim 16  further comprising a booster adjacent to an end of the detonating cord within the tube to ignite the detonating cord.