Devices and Methods for Electromagnetic Measurement of Axial Flow

Abstract

An embodiment method for measuring fluid flow in a casing includes inserting a logging tool into the casing, wherein the logging tool having an internal axial flow channel and an electromagnetic flowmeter sensor disposed in the internal flow channel. The method also includes measuring an axial conductive fluid flow through the flow channel with the electromagnetic flowmeter sensor, while allowing bypass axial fluid flow to bypass the internal flow channel substantially unimpeded between an exterior of the logging tool and an interior wall of the casing.

What is claimed is: 
     
         1 . A method for measuring fluid flow in a casing, the method comprising:
 inserting a logging tool into the casing, the logging tool having an internal axial flow channel and an electromagnetic flowmeter sensor disposed in the internal flow channel; and   measuring an axial conductive fluid flow through the flow channel with the electromagnetic flowmeter sensor, while allowing bypass axial fluid flow to bypass the internal flow channel substantially unimpeded between an exterior of the logging tool and an interior wall of the casing.   
     
     
         2 . The method of  claim 1 , further comprising generating a magnetic flux inside the flow channel orthogonal to the axial fluid flow through the flow channel. 
     
     
         3 . The method of  claim 2 , wherein the electromagnetic flowmeter sensor comprises a pair of electrodes disposed in the flow channel, wherein an imaginary line between the pair of electrodes is orthogonal to the magnetic flux and to the axial fluid flow through the flow channel, and wherein the measuring comprises measuring a voltage difference between the pair of electrodes, wherein the voltage difference is proportional to a velocity of the axial conductive fluid flow. 
     
     
         4 . The method of  claim 1 , further comprising repeating the measuring at different depths in the casing. 
     
     
         5 . The method of  claim 1 , further comprising centering the flow channel in the casing prior to the measuring. 
     
     
         6 . A method for measuring fluid flow in a casing, the method comprising:
 inserting a logging tool into the casing, the logging tool comprising a tool body and an electromagnetic flowmeter sensor, wherein the electromagnetic flow sensor has a pair of electrodes disposed on an exterior of the tool body; and   measuring an axial conductive fluid flow in the casing with the pair of electrodes of the electromagnetic flowmeter sensor, wherein an imaginary line between the pair of electrodes is orthogonal to the axial conductive fluid flow.   
     
     
         7 . The method of  claim 6 , further comprising generating a magnetic flux orthogonal to the axial fluid flow and to the imaginary line between the pair of electrodes. 
     
     
         8 . The method of  claim 6 , wherein the measuring comprises measuring a voltage difference between the pair of electrodes, wherein the voltage difference is proportional to a velocity of the axial conductive fluid flow. 
     
     
         9 . The method of  claim 6 , wherein the logging tool further comprises a plurality of electromagnetic flowmeter sensors each having a respective pair of electrodes disposed on the exterior of the tool body, and wherein the measuring further comprises, for each respective pair of electrodes, measuring a voltage difference between the respective pair of electrodes, wherein the voltage difference is proportional to a velocity of the axial conductive fluid flow between the respective pair of electrodes. 
     
     
         10 . The method of  claim 9 , wherein the measuring further comprises measuring the axial conductive fluid flow at multiple angular locations around a perimeter of the tool body. 
     
     
         11 . A logging tool for measuring fluid flow in a casing, the logging tool comprising:
 an elongated tool body having a central axis;   a first non-centralized flow channel mechanically coupled to the tool body, wherein a first axis of the first flow channel is parallel to the central axis of the tool body, and wherein the first flow channel is radially offset from the central axis of the tool body;   a first electromagnetic flowmeter sensor, wherein the first electromagnetic flow sensor has a first pair of electrodes disposed inside the first flow channel, wherein a first imaginary line between the first pair of electrodes is orthogonal to the first axis of the first flow channel;   a second non-centralized flow channel mechanically coupled to the tool body, wherein a second axis of the second flow channel is parallel to the central axis of the tool body, and wherein the second flow channel is radially offset from the central axis of the tool body; and   a second electromagnetic flowmeter sensor, wherein the second electromagnetic flow sensor has a second pair of electrodes disposed inside the second flow channel, wherein a second imaginary line between the second pair of electrodes is orthogonal to the second axis of the second flow channel.   
     
     
         12 . The logging tool of  claim 11 , wherein:
 the first electromagnetic flowmeter sensor comprises a first magnetic flux generator configured to generate a first magnetic flux orthogonal both to the first imaginary line between the first pair of electrodes and to the first axis of the first flow channel; and   the second electromagnetic flowmeter sensor comprises a second magnetic flux generator configured to generate a second magnetic flux orthogonal both to the second imaginary line between the second pair of electrodes and to the second axis of the second flow channel.   
     
     
         13 . The logging tool of  claim 11 , wherein the tool body has a scalloped-out section, and wherein the first and second flow channels are disposed on the tool body in the scalloped-out section. 
     
     
         14 . The logging tool of  claim 11 , wherein each of the first and second flow channels is partially embedded in a side of the tool body, and has an open side radially away from the tool body. 
     
     
         15 . The logging tool of  claim 11 , wherein there are multiple pairs of electrodes disposed in each of the flow channels. 
     
     
         16 . A logging tool for measuring fluid flow in a casing, the logging tool comprising:
 an elongated tool body having a central axis;   a plurality of electromagnetic flowmeter sensors mechanically coupled to the tool body and disposed in a first plane perpendicular to the central axis of the tool body, wherein each of the electromagnetic flowmeter sensors has a flow channel with a flow channel axis parallel to the central axis of the tool body.   
     
     
         17 . The logging tool of  claim 16 , further comprising additional electromagnetic flowmeter sensors mechanically coupled to the tool body, and disposed in a second plane perpendicular to the central axis of the tool body different from the first plane. 
     
     
         18 . The logging tool of  claim 16 , wherein the electromagnetic flowmeter sensors are configured to move radially inward toward and outward from the tool body, and/or rotate about the central axis of the tool body. 
     
     
         19 . The logging tool of  claim 16 , wherein the electromagnetic flowmeter sensors are mounted on a plurality of arms mechanically coupled to the tool body. 
     
     
         20 . The logging tool of  claim 19 , wherein more than one of the electromagnetic flowmeter sensors is mounted on one of the arms.