Systems and Methods for Selective Electrical Isolation of Downhole Tools

Abstract

Systems and methods for electrically isolating selected ones of a set of downhole tools that are connected to a common electrical cable. In one embodiment, a system includes surface equipment, a plurality of downhole tools and a common electrical cable. The downhole tools are connected to the cable by coupling switches. Each switch has a closed position in which the downhole tool is electrically coupled to the cable and an open position in which the downhole tool is electrically decoupled from the cable. The coupling switches are remotely actuated by placing an actuating device in proximity to the switches, thereby alternately coupling the corresponding downhole tools to the common cable or isolating the tools from the cable.

1 . A system comprising:
 surface equipment positioned at the surface of a well;   a cable coupled to the surface equipment, wherein the cable extends into a wellbore of the well; and   a plurality of downhole tools, wherein at least a first one of the downhole tools is connected to the cable by a switch, wherein the switch has a closed position in which the downhole tool is electrically coupled to the cable and an open position in which the downhole tool is electrically decoupled from the cable, wherein the switch is configured to be actuated to move between the open and closed positions while the first one of the downhole tools is positioned downhole in the wellbore.   
     
     
         2 . The system of  claim 1 , wherein the first one of the downhole tools is configured to be selectively coupled to or decoupled from the cable independently of other ones of the plurality of downhole tools. 
     
     
         3 . The system of  claim 1 , wherein the first one of the downhole tools comprises a sensor. 
     
     
         4 . The system of  claim 1 , wherein the first one of the downhole tools comprises a control device. 
     
     
         5 . The system of  claim 1 , wherein the switch is configured to be actuated by a magnet which is positioned in close proximity to the switch. 
     
     
         6 . The system of  claim 1 , wherein the cable comprises a conductor which is configured to provide power to ones of the plurality of downhole tools that are coupled to the cable. 
     
     
         7 . The system of  claim 6 , wherein the cable is further configured to carry data to or from ones of the plurality of downhole tools that are coupled to the cable. 
     
     
         8 . The system of  claim 1 , wherein the cable comprises a conductor which is configured to carry data to or from ones of the plurality of downhole tools that are coupled to the cable. 
     
     
         9 . The system of  claim 1 , wherein the first one of the downhole tools further comprises a fuse connected between the downhole tool and the cable. 
     
     
         10 . An apparatus comprising:
 a downhole tool having one or more electrical components that are configured to be coupled to a conductor external to the downhole tool;   a coupling configured to be coupled to the conductor external to the downhole tool; and   a switch connected between the electronic components and the coupling;   wherein when the switch is in a closed position the electronic components are electrically connected to the coupling, and wherein when the switch is in an open position the electronic components are electrically isolated from the coupling; and   wherein the switch is configured to be actuated by an actuating device which is external to the downhole tool.   
     
     
         11 . The apparatus of  claim 10 , wherein the downhole tool comprises a sensor. 
     
     
         12 . The apparatus of  claim 10 , wherein the downhole tool comprises a control device. 
     
     
         13 . The apparatus of  claim 10 , further comprising a fuse coupled between the one or more electrical components and the switch. 
     
     
         14 . A method comprising:
 positioning a plurality of downhole tools within a wellbore of a well, wherein each of the plurality of downhole tools is connected to a common cable via a corresponding switch;   positioning an actuating device in close proximity to a first one of the downhole tools; and   actuating the switch coupled between the first one of the downhole tools and the common cable, thereby moving the switch between a closed position in which the downhole tool is electrically coupled to the cable and an open position in which the downhole tool is electrically isolated from the cable.   
     
     
         15 . The method of  claim 14 , wherein the switch coupled between the first one of the downhole tools and the common cable is actuated independently of switches connected to other ones of the downhole tools. 
     
     
         16 . The method of  claim 14 , wherein actuating the switch coupled between the first one of the downhole tools and the common cable comprises positioning a magnet in close proximity to the switch. 
     
     
         17 . The method of  claim 14 , further comprising detecting a malfunction associated with the first one of the downhole tools, wherein the switch coupled between the first one of the downhole tools and the common cable is actuated in response to detecting the malfunction.