Distributed Fluid Velocity Sensor and Associated Method

Abstract

Device and method for performing distributed fluid velocity measurement. An elongate device comprising along its length, a heated core ( 200 ), at least one outer layer ( 240 ) around the core, the outside surface of the outer layer ( 240 ) defining an outside surface of the device, and a distributed temperature sensor ( 230 ) located between the heated core ( 200 ) and the outside surface of the device. The method immerses the device in one or more fluids along its length, measures the ambient temperature of the fluids at points along it's length, heats the heated core ( 200 ) for a predetermined heating period and measures the temperature again at the same points. Using pre-installed knowledge the device can obtain distributed and/or point fluid velocity measurements.

1 . An elongate device for performing distributed fluid velocity measurement, comprising along its length:
 a heated core,   at least one outer layer around said core, the outside surface of said at least one outer layer defining an outside surface of the device, and   a distributed temperature sensor;   wherein said distributed temperature sensor is located between the heated core and the outside surface of the device.   
     
     
         2 . A device as claimed in  claim 1  wherein said distributed temperature sensor comprises a fibre-optic distributed temperature sensor. 
     
     
         3 . A device as claimed in  claim 1  wherein said distributed temperature sensor is coiled helically around said heated core. 
     
     
         4 . A device as claimed in  claim 1  wherein said distributed temperature sensor is embedded within an insulation layer around said heated core. 
     
     
         5 . A device as claimed in  claim 4  wherein there is at least one intervening layer between said insulation layer having said distributed temperature sensor embedded therein and said heated core. 
     
     
         6 . A device as claimed in  claim 1  wherein said device comprises a cable. 
     
     
         7 . A device as claimed in  claim 1  wherein said heated core comprises a resistance wire. 
     
     
         8 . A device as claimed in  claim 1  comprising control and processing means for controlling the heating of the heated core and processing the results obtained from the distributed temperature sensor. 
     
     
         9 . A device as claimed in  claim 1  comprising a distributed fluid identification device for identifying a fluid in which said device is immersed. 
     
     
         10 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . A device as claimed in  claim 1  comprising a semi rigid construction to allow it to be injected into well bores. 
     
     
         17 . A device as claimed in  claim 16  comprising a rigid element such as carbon fibre along its length. 
     
     
         18 . A plurality of devices as claimed in  claim 1  being operable to provide a 3-dimensional array of measurement points within a fluid in which said plurality of devices is immersed. 
     
     
         19 . A method of performing distributed fluid velocity measurements using at least one elongate device comprising along its length: a heated core, at least one outer layer around said core, the outside surface of said at least one outer layer defining an outside surface of the device, and a distributed temperature sensor; wherein said distributed temperature sensor is located between the heated core and the outside surface of the device; the method comprising the steps of:
 immersing said device(s) in one or more fluids along its length;   measuring the ambient temperature of said fluid or fluids at a plurality of measurement points along its length;   turning on the heated core for a predetermined heating period: and   measuring the temperature again at the same measurement points.   
     
     
         20 . A method as claimed in  claim 19  further comprising the use of obtained or pre-installed knowledge of the appropriate fluid characteristics so as to process said distributed cooling measurements to obtain distributed and/or point fluid velocity measurements for the fluid or fluids passing over the surface of said device or devices. 
     
     
         21 . A method as claimed in  claim 20  further comprising the step of determining the real-time distributed and/or point fluid flow information from said distributed and/or point fluid velocity measurements. 
     
     
         22 . A method as claimed in  claim 20  further comprising said method comprises obtaining information to identify said fluid or fluids at the same time as performing said distributed cooling measurements. 
     
     
         23 . A method as claimed in  claim 19  further comprising using obtained or pre-installed knowledge of a number of fluid characteristics to identify which of said number of fluids it is immersed in at any one measurement point directly from the measured temperature at said measurement point after said predetermined heating. 
     
     
         24 . A method as claimed in  claim 19  comprising the initial step of deploying said device or devices in a well bore. 
     
     
         25 . A method as claimed in  claim 19  comprising the initial step of deploying said device or devices in a pipeline so as to detect and/or locate leaks and/or branches, and/or to determine flow rates therein. 
     
     
         26 . A method as claimed in  claim 19  comprising the initial step of deploying said device or devices in a fluid storage facility such as a tank, reservoir or separator.