ELECTROMAGNETIC TELEMETRY GAP SUB ASSEMBLY WITH INSULATING COLLAR

摘要

An insulating collar for a gap sub assembly for electromagnetic (EM) telemetry used in downhole drilling is disclosed. The gap sub assembly comprises a female member comprising a female mating section and a male member comprising a male mating section and a gap section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. The insulating collar is positioned on the gap section. The collar is made up of a framework with a plurality of discrete bodies spaced about the framework and a portion of each of the discrete bodies protrudes above the framework. Either the framework or the discrete bodies are made of an electrical insulator material to electrically isolate one end of the collar from the other end of the collar. The collar therefore electrically isolates the male member from the female member and the male member, female member and insulating collar function as the "gap sub" for EM telemetry.