Measurement of Torque with Shear Stress Sensors

Abstract

A torque measurement tool and method of use is presented which comprises a first outer shaft extending along a longitudinal axis and containing a second inner shaft positioned within the first outer shaft and extending along the longitudinal axis. A flexible coupling is positioned between the first outer shaft and the second inner shaft. A shear stress sensor is positioned within the second inner shaft, is exposed to the first outer shaft and contacts the flexible coupling.

What is claimed is: 
     
         1 . A torque measurement tool, comprising:
 a first shaft extending along a longitudinal axis;   a second shaft positioned within the first shaft and extending along the longitudinal axis, the second shaft including a hollow cavity;   a flexible coupling positioned between the first and second shafts, the flexible coupling coupled to a first surface of the first shaft and to a second surface of the second shaft; and   a shear stress sensor positioned within the first shaft, the shear stress sensor exposed to the first surface of the first shaft and abutting the flexible coupling.   
     
     
         2 . The tool of  claim 1 , wherein the hollow cavity is a drilling fluid cavity. 
     
     
         3 . The tool of  claim 1 , wherein the flexible coupling is selected from the group consisting of: silicone rubber; urethane rubber; natural rubber; styrene-butadiene-rubber; butylrubber; polyurethane; polychloroprene; nitrile; hydrogenated nitrile; chlorosulphonated polyethylene; fluorosilicone; fluorocarbon; and combinations thereof. 
     
     
         4 . The tool of  claim 1 , wherein the shear stress sensor comprises a micro-electro-mechanical system (MEMS) shear stress sensor. 
     
     
         5 . The tool of  claim 1 , wherein the first shaft comprises a channel housing a cable coupled to the shear stress sensor. 
     
     
         6 . A method, comprising:
 conveying a torque measurement tool into a torsion-inducing environment, the torque measurement tool comprising multiple concentric shafts and a flexible coupling positioned between the multiple concentric shafts, the torque measurement tool also comprising a shear stress sensor abutting the flexible coupling, wherein the shear stress sensor is positioned on an inner surface of the outermost shaft, the surface facing a longitudinal axis of the outermost shaft;   causing torque to be applied to an outermost shaft of the multiple concentric shafts, the torque resulting in a positional displacement between the outermost shaft and an inner shaft positioned inside the outermost shaft;   using the shear stress sensor to measure shear stress in the flexible coupling resulting from the application of the torque to the outermost shaft; and   adjusting operations using the shear stress measurement.   
     
     
         7 . The method of  claim 6 , wherein the shear stress sensor comprises a micro-electro-mechanical system (MEMS) shear stress sensor. 
     
     
         8 . The method of  claim 6 , wherein the inner shaft comprises a drilling fluid cavity. 
     
     
         9 . The method of  claim 6 , wherein the outermost shaft comprises a channel housing a cable coupled to the shear stress sensor. 
     
     
         10 . The method of  claim 6 , wherein the flexible coupling is selected from the group consisting of: silicone rubber; urethane rubber; natural rubber; styrene-butadiene-rubber; butylrubber; polyurethane; polychloroprene; nitrile; hydrogenated nitrile; chlorosulphonated polyethylene; fluorosilicone; fluorocarbon; and combinations thereof. 
     
     
         11 . A torque measurement tool, comprising:
 an outer cylindrical shaft extending along a longitudinal axis and having an inner bore with an inner surface;   an inner cylindrical shaft positioned within the inner bore of the outer cylindrical shaft and extending along the longitudinal axis, the inner cylindrical shaft having an outer surface and an inner bore with an inner surface;   a flexible coupling positioned within an annular space between the inner surface of the outer cylindrical shaft and the outer surface of the inner cylindrical shaft, the flexible coupling directly coupled to the inner surface of the outer cylindrical shaft and to the outer surface of the inner cylindrical shaft such that the flexible coupling couples the outer surface of the inner cylindrical shaft with the inner surface of the outer cylindrical shaft; and   a micro-electro-mechanical-system (MEMS) shear stress sensor positioned within a recess located on the inner surface of the outer cylindrical shaft, the shear stress sensor having a contact surface positioned about flush to the inner surface of the outer cylindrical shaft and in contact with the flexible coupling.   
     
     
         12 . The tool of  claim 11 , wherein the inner bore of the inner cylindrical shaft allows drilling fluid to flow through the tool. 
     
     
         13 . The tool of  claim 11 , wherein the outer cylindrical shaft includes a channel, and wherein the channel houses a cable coupled to the shear stress sensor. 
     
     
         14 . The tool of  claim 13 , wherein the outer cylindrical shaft includes a channel, and wherein the channel houses a cable coupled to the shear stress sensor. 
     
     
         15 . The tool of  claim 11 , wherein the flexible coupling is selected from the group consisting of: silicone rubber; urethane rubber; natural rubber; styrene-butadiene-rubber; butylrubber; polyurethane; polychloroprene; nitrile; hydrogenated nitrile; chlorosulphonated polyethylene; fluorosilicone; fluorocarbon; and combinations thereof. 
     
     
         16 . A method, comprising:
 conveying a torque measurement tool into a torsion-inducing environment, the torque measurement tool comprising:   an outer cylindrical shaft extending along a longitudinal axis and having an inner bore with an inner surface;   an inner cylindrical shaft positioned within the inner bore of the outer cylindrical shaft and extending along the longitudinal axis, the inner cylindrical shaft having an outer surface and an inner bore with an inner surface;   a flexible coupling positioned within an annular space between the inner surface of the outer cylindrical shaft and the outer surface of the inner cylindrical shaft, the flexible coupling directly coupled to the inner surface of the outer cylindrical shaft and to the outer surface of the inner cylindrical shaft such that the flexible coupling couples the outer surface of the inner cylindrical shaft with the inner surface of the outer cylindrical shaft; and   a micro-electro-mechanical-system (MEMS) shear stress sensor positioned within a recess located on the inner surface of the outer cylindrical shaft, the shear stress sensor having a contact surface positioned about flush to the inner surface of the outer cylindrical shaft and in contact with the flexible coupling;   causing torque to be applied to the outer cylindrical shaft, the torque resulting in a positional displacement between the outer cylindrical shaft and the inner cylindrical shaft positioned inside the outer cylindrical shaft;   using the shear stress sensor to measure shear stress in the flexible coupling resulting from the torque applied to the outer cylindrical shaft; and   adjusting operations using the shear stress measurement.   
     
     
         17 . The method of  claim 16 , wherein the outer cylindrical shaft comprises a channel housing a cable coupled to the shear stress sensor. 
     
     
         18 . The method of  claim 16 , wherein the inner bore of the inner cylindrical shaft allows drilling fluid to flow through the tool. 
     
     
         19 . The method of  claim 17 , wherein the inner bore of the inner cylindrical shaft allows drilling fluid to flow through the tool. 
     
     
         20 . The method of  claim 16 , wherein the flexible coupling is selected from the group consisting of: silicone rubber; urethane rubber; natural rubber; styrene-butadiene-rubber; butylrubber; polyurethane; polychloroprene; nitrile; hydrogenated nitrile; chlorosulphonated polyethylene; fluorosilicone; fluorocarbon; and combinations thereof.