Downhole Electromagnetic Telemetry System Utilizing Electrically Insulating Material and Related Methods

Abstract

A downhole electromagnetic telemetry system and method whereby electrically insulating material is placed above and/or below an electrical current launching device or receiver along a well string in order to extend the range of the telemetry system, increase the telemetry rate, and/or reduce downhole power requirements.

What is claimed is: 
     
         1 . A method for utilizing an electromagnetic telemetry system in a downhole well, the method comprising:
 providing a well string comprising one or more tubulars attached to a bottom hole assembly, the bottom hole assembly comprising at least one of an electrical current launching device or a receiver;   applying electrically insulating material around one or more portions of the well string;   deploying the bottom hole assembly into the well;   conducting an electromagnetic telemetry operation using the bottom hole assembly; and   utilizing the electrically insulating material to reduce at least one of:
 short circuits from the current launching device to casing; or 
 current leakage from the well string into the casing or formation along the well. 
   
     
     
         2 . A method as defined in  claim 1 , further comprising applying the electrically insulating material around one or more portions of the well string immediately above or below the current launching device or receiver. 
     
     
         3 . A method as defined in  claim 1 , wherein applying the electrically insulating material around the one or more portions of the well string comprises wrapping the one or more portions of the well string with one or more sheets of electrically insulating material. 
     
     
         4 . A method as defined in  claim 1 , wherein applying the electrically insulating material around the one or more portions of the well string comprises positioning an insulation sleeve around the one or more portions of the well string, the insulation sleeve being comprised of electrically insulating swellable material. 
     
     
         5 . A method as defined in  claim 1 , wherein applying the electrically insulating material around the one or more portions of the well string comprises applying at least one of:
 an electrically insulating swellable material;   an electrically insulating injection-molded coating;   an electrically insulating spray coating; or   an electrically insulating anodized layer.   
     
     
         6 . A method as defined in  claim 1 , wherein applying the electrically insulating material around the one or more portions of the well string comprises:
 determining a length of an electrically conductive portion of the formation along the well; and   applying the electrically insulating material based upon the determined length.   
     
     
         7 . An electromagnetic telemetry system for use in a downhole well, the system comprising:
 a well string comprising one or more tubulars attached to a bottom hole assembly, the bottom hole assembly comprising at least one of an electrical current launching device or a receiver; and   electrically insulating material positioned around one or more portions of the well string to reduce at least one of:
 short circuits from the current launching device to casing; or 
 current leakage from the well string into the casing or formation along the well. 
   
     
     
         8 . A system as defined in  claim 7 , wherein the electrically insulating material is positioned immediately above or below the current launching device or receiver. 
     
     
         9 . A system as defined in  claim 7 , wherein the electrical current launching device is a gap sub assembly or a toroid. 
     
     
         10 . A system as defined in  claim 7 , wherein the receiver is a gap sub assembly or a toroid. 
     
     
         11 . A system as defined in  claim 7 , wherein the electrically insulating material is one or more sheets of electrically insulating material. 
     
     
         12 . A system as defined in  claim 7 , wherein the electrically insulating material is an insulation sleeve. 
     
     
         13 . A system as defined in  claim 7 , wherein the electrically insulating material is at least one of:
 an electrically insulating swellable material;   an electrically insulating injection-molded coating;   an electrically insulating spray coating; or   an electrically insulating anodized layer.   
     
     
         14 . A method for utilizing an electromagnetic telemetry system in a downhole well, the method comprising:
 applying electrically insulating material around one or more portions of a well string comprising at least one of an electrical current launching device or a receiver; deploying the well string into the well; and   utilizing the electrically insulating material to reduce at least one of:
 short circuits from the current launching device to casing; or 
 current leakage from the well string into the casing or formation along the well. 
   
     
     
         15 . A method as defined in  claim 14 , further comprising applying the electrically insulating material around one or more portions of the well string immediately above or below the current launching device or receiver. 
     
     
         16 . A method as defined in  claim 14 , wherein applying the electrically insulating material around the one or more portions of the well string comprises applying at least one of:
 an electrically insulating swellable material;   an electrically insulating injection-molded coating;   an electrically insulating spray coating; or   an electrically insulating anodized layer.   
     
     
         17 . A method as defined in  claim 14 , wherein applying the electrically insulating material around the one or more portions of the well string comprises:
 determining a length of an electrically conductive portion of the formation along the well; and   applying the electrically insulating material based upon the determined length.