Inductive data transmission system

Abstract

A downhole tubular which may include a drill pipe, or a portion of a drill pipe or other downhole tool or riser, comprising a threaded pin end and a threaded box end as well as one or more annular shoulders circumscribing the pin end and the box end adjacent to the respective threads. The annular shoulders each comprising an annular groove within the annular shoulders coaxial with the respective annular shoulders, the respective annular grooves comprising side and bottom groove walls. The groove walls may have a hardness as measured on a Rockwell C scale greater than the respective annular shoulders proximate the respective annular grooves. A magnetically conductive electrically insulating (MCEI) U-shaped annular trough may be disposed within the annular grooves. An electrically conductive wire coil may be disposed within the MCEI U-shaped annular trough comprising a transmission end and a ground end to aid in downhole communication.

1 . A downhole tubular, comprising:
 a drill pipe comprising a threaded pin end and a threaded box end, annular shoulders circumscribing the pin end and the box end adjacent to the respective threads, the annular shoulders each comprising an annular groove coaxial with the respective annular shoulders, the respective annular grooves comprising side and bottom groove walls;   the side and bottom groove walls having a hardness as measured on a Rockwell C scale greater than the respective annular shoulders proximate the respective annular grooves;   a magnetically conductive electrically insulating (MCEI) U-shaped annular trough disposed within the annular grooves;   an electrically conductive wire coil disposed within the MCEI U-shaped annular trough comprising a transmission end and a ground end; and   the ground end being attached to the bottom wall of the annular groove, and the transmission end being connected to a cable within the drill pipe.   
     
     
         2 . The downhole tubular of  claim 1 , wherein the groove walls have a hardness as measured on the Rockwell C scale of between 0.05% and 5.0% greater than the annular shoulders adjacent the groove walls. 
     
     
         3 . The downhole tubular of  claim 1 , wherein the MCEI U-shaped annular trough comprises a plurality of MCEI U-shaped trough segments. 
     
     
         4 . The downhole tubular of  claim 3 , wherein the MCEI U-shaped trough segments comprise a composition of one or more of oxygen and transition metals on the Periodic Table or a combination thereof. 
     
     
         5 . The downhole tubular of  claim 4 , wherein the composition comprises one or more of magnesium, calcium, beryllium, or a combination thereof. 
     
     
         6 . The downhole tubular of  claim 4 , wherein the composition comprises particles having an average particle diameter of between 350 μm and 1250 μm. 
     
     
         7 . The downhole tubular of  claim 4 , wherein the composition comprises particles having an average particle diameter of between 600 nm and 900 nm. 
     
     
         8 . The downhole tubular of  claim 4 , wherein the average particle distribution within the powder composition is about between 8:2 and 2:8, respectively. 
     
     
         9 . The downhole tubular of  claim 1 , wherein the annular shoulder comprises a region less hard as measured the Rockwell C scale than the annular shoulder adjacent the side groove wall region. 
     
     
         10 . The downhole tubular of  claim 1 , wherein the annular groove further comprises an annular insert mounted within the annular groove comprising a Rockwell hardness greater than the Rockwell hardness of the annular shoulder adjacent the groove. 
     
     
         11 . The downhole tubular of  claim 1 , wherein the annular groove comprises deformed wall surfaces. 
     
     
         12 . The downhole tubular of  claim 11 , wherein the annular groove comprises a hardened region extending from the deformed wall surfaces into the annular shoulder a distance between 0.001 mm to 3 mm. 
     
     
         13 . The downhole tubular of  claim 11 , wherein the deformed wall surfaces of the annular groove comprise indentations. 
     
     
         14 . The downhole tubular of  claim 11 , wherein the deformed wall surfaces of the annular groove comprise indentations produced by means of peening, shot peening, hammer peening, laser peening, ultra-sonic peening, grit peening, glass peening, or a combination thereof. 
     
     
         15 . The downhole tubular of  claim 14 , wherein the indentations exhibit a non-uniform depth. 
     
     
         16 . The downhole tubular of  claim 3 , wherein at least one U-shaped trough segment comprises two or more enclosed orifices running normal to the longitudinal axis of the segment. 
     
     
         17 . The downhole tubular of  claim 3 , wherein one end of the wire coil passes through the enclosed orifice of the U-shaped trough segment to ground while the other end passes through another enclosed orifice to the cable. 
     
     
         18 . The downhole tubular of  claim 3 , wherein the U-shaped trough segments provide a substantially gap free U-shaped annular trough. 
     
     
         19 . The downhole tubular of  claim 3 , wherein at least one enclosed orifice provides a means for locating the U-shaped annular trough within the annular groove. 
     
     
         20 . The downhole tubular of  claim 3 , wherein at least one enclosed orifice provides a means for securing the U-shaped annular trough segments within the annular groove.