Downhole Flow Measurement In A Well

Abstract

A method for downhole flow measurement comprises installing a fibre optical distributed temperature sensor (DTS) system along at least part of the length of an inflow region of the well and using the sensor to measure fluctuations of the temperature of fluids flowing from the formation into the well and the velocity at which said natural fluctuations migrate in downstream direction through the well. The measured temperature variations may be low frequency temperature fluctuations of between 0.1 and 0.5 Degrees Celsius, which gradually die out downstream of the inflow region(s) of the well.

1 . A method for downhole flow measurement in a well, the method comprising installing a fibre optical distributed temperature sensor (DTS) system along at least part of the length of an inflow region of the well and using the sensor to measure one or more fluctuations of the temperature of fluids flowing from the formation into the well and the velocity at which at least one of said natural fluctuations migrates in a downstream direction through the well.  
   
   
       2 . The method of  claim 1 , wherein the DTS system is configured to track the downstream migration through the well of low frequency temperature fluctuations of less than 1 Degree Celsius.  
   
   
       3 . The method of  claim 2 , wherein the DTS system is configured to track the downstream migration through the well of natural low frequency temperature variations between 0.1 and 0.5 Degrees Celsius.  
   
   
       4 . The method of  claim 1 , wherein the DTS system extends along at least a substantial part of the length of an inflow region of the well and the method is used to assess the fluid inflow rate at different locations along the length of the inflow region on the basis of measured variations of the velocity of the fluids in a longitudinal direction along at least part of the length of said inflow region.  
   
   
       5 . The method of  claim 1 , wherein the well is a hydrocarbon fluid production well.  
   
   
       6 . The method of  claim 1 , wherein the fluids flowing into the well comprise gaseous components and or components which at least partly evaporate in the inflow region and the fluid production rate of the well is cyclically varied over time.  
   
   
       7 . The method of  claim 6 , wherein the fluid production rate of the well is cyclically varied by cyclic variation of the opening of a production choke or downhole valve or by initiating a slug flow regime in the well or in the production flowline or processing equipment downstream of the wellhead.