Open Hole Casing Run Perforating Tool

Abstract

Disclosed is an open-hole casing perforation tool having projecting fins around the circumference of a mandrel that have firing mechanisms and shape charges to allow flexible operation of geological formation fracturing at desired predetermined locations in an oil or gas well bore.

1 . A tool for perforating or shock loading a geological formation comprising:
 a mandrel, a series of projections, fins, located around the outer circumference of the mandrel, wherein at least one of the fins houses a firing head assembly.   
     
     
         2 . The tool of  claim 1  wherein the ends of the mandrel are threaded to connect to a threaded end of casing or enlarged to be fitted over the end of casing and secured by locking rings or pins. 
     
     
         3 . The tool of  claim 1  wherein the fins are oriented longitudinally, laterally, and helically in reference to the orientation of the casing string. 
     
     
         4 . The tool of  claim 1  wherein the fins are disposed on a skeletal frame that is constructed to slide over a casing and is held in place with locking rings. 
     
     
         5 . The tool of  claim 1  wherein shape charges are disposed in the fins and wherein one or more directed inward toward the well. 
     
     
         6 . The tool of  claim 5  also comprising a detonation cord that is connected to ignition port(s) of shape charges located in a manner to explode in a predetermined direction. 
     
     
         7 . The tool of  claim 5  wherein the shaped charges are selected from the group consisting of; deep penetrating charges, big hole charges designed for optimal hole size, punch charges designed for limited penetration, charges that incorporate reactive liner technology and linear shaped charges that produce slot shaped holes. 
     
     
         8 . The tool of  claim 1  wherein the firing head assembly comprises a pressure activated release mechanism, a firing pin, an initiator percussion unit that ignites a detonation cord, housed in a suitable body that can be attached to fins of the perforating tools in a configuration to allow the initiation of detonation of shape charges located in the fins. 
     
     
         9 . The tool of  claim 8  wherein the pressure activated release mechanism is a rupture disc or a shear pin retained firing system. 
     
     
         10 . The tool of  claim 8  wherein the pressure activated release mechanism for each fin has a release mechanism set at a predetermined release setting that may be the same or different for individual fins. 
     
     
         11 . The tool of  claim 8  wherein the pressure activated release mechanism is comprised of a reverse acting rupture disc. 
     
     
         12 . The tool of  claim 8  wherein the firing head assembly is modular and interchangeable from one tool assembly to another and configured to be easily removable from the tool. 
     
     
         13 . The tool of  claim 8  wherein the firing head assemblies are configured to allow interchange of initiation means. 
     
     
         14 . The tool of  claim 8  wherein the firing head assembly also comprises a time delay means to delay the time from activation to release. 
     
     
         15 . The tool of  claim 14  wherein the firing head assembly time delay means is selected from the group consisting of a time delay fuse, a mechanical means, a hydraulic means, a delay mechanism that is configured to interact with the fracture treatment, and a delay mechanism configured to preferentially orient banks of charges to fire in conjunction with the fracture treatment. 
     
     
         16 . A firing head assembly for a tool comprising a pressure activated release mechanism, a firing pin assembly, and an initiator percussion unit that ignites a detonation means. 
     
     
         17 . The firing pin assembly of  claim 16  wherein the pressure release mechanism comprises a reverse acting rupture disc. 
     
     
         18 . The firing head assembly of  claim 16  also comprising a shear pin located between the release mechanism and the percussion unit. 
     
     
         19 . A method of perforating or shock loading a geological formation comprising;
 providing a tool comprising a mandrel having a series projections, fins disposed around the outer circumference, wherein each projection houses a firing head assembly connected to a detonation means that is connected to an ignition port(s) of shape charges located in the projections in an manner to explode outward the mandrel surface, locating the tool in a desired location of a well casing; and   activating the firing head assembly so as to initiate the shape charges.   
     
     
         20 . The method of  claim 19  wherein the firing head assembly comprises a pressure activated release mechanism, a firing pin, an initiator percussion unit that ignites a detonation means, attached to fins of a tool in a configuration to allow the initiation of detonation of shape charges located in the fins. 
     
     
         21 . The method of  claim 19  wherein the pressure activated release mechanism is a rupture disc and the activating means is pressure. 
     
     
         22 . The method of  claim 19  wherein the firing head assembly has at least one firing initiator set at a lower activation level than the remaining assemblies so that when activated the pressure produced activated the remaining firing head assemblies; 
     
     
         23 . The method of  claim 19  wherein there is a first and secondary firing assembly on separate fins and detonation is initiated in a secondary firing assembly by means of a secondary mechanism. 
     
     
         24 . The method of  claim 23  wherein the detonation means is initiated in a secondary firing assembly by means of pressure transmission from a first firing assembly. 
     
     
         25 . The method of  claim 19  wherein a plurality of perforating tools are arranged in one or more stages in which the tools are disposed in a casing string sealed by packers and wherein there is a first and second tool and wherein activation of a first tool acts to initiate the function of the second tool. 
     
     
         26 . The method of  claim 19  wherein perforating tools are arranged in one or more stages in which the tools in each stage are disposed in a casing string sealed by packers and wherein activation of a first tool in one stage acts to activate a tool in another separate stage.