Downhole monitoring with distributed acoustic/vibration, strain and/or density sensing

Abstract

Distributed acoustic, vibration, density and/or strain sensing is utilized for downhole monitoring. A method of tracking fluid movement along a wellbore of a well includes: detecting vibration, density, strain (static and/or dynamic) and/or Brillouin frequency shift in the well using at least one optical waveguide installed in the well; and determining the fluid movement based on the detected vibration, density, strain and/or Brillouin frequency shift. Another method of tracking fluid movement along a wellbore of a well includes: detecting a change in density of an optical waveguide in the well; and determining the fluid movement based on the detected density change.

1 - 6 . (canceled) 
     
     
         7 . A method of tracking fluid movement along a wellbore of a well, the method comprising:
 detecting strain in the well using at least one optical waveguide installed in the well; and   determining the fluid movement based on the detected strain.   
     
     
         8 . The method of  claim 7 , wherein the detecting step further comprises detecting coherent phase Rayleigh backscattering due to light transmitted through the at least one optical waveguide. 
     
     
         9 . The method of  claim 7 , wherein the detecting step further comprises detecting Brillouin backscattering due to light transmitted through the at least one optical waveguide. 
     
     
         10 . The method of  claim 7 , wherein the detecting step further comprises detecting a change in an optical path length through the at least one optical waveguide. 
     
     
         11 . The method of  claim 7 , wherein the detecting step further comprises detecting density change in the at least one optical waveguide, the density change producing a frequency shift in light transmitted through the at least one optical waveguide. 
     
     
         12 . The method of  claim 7 , wherein the detecting step further comprises detecting a wavelength shift for light reflected off of a Bragg grating. 
     
     
         13 . The method of  claim 7 , further comprising the step of introducing a property change into the fluid, whereby movement of the property change with the fluid generates the strain. 
     
     
         14 . The method of  claim 13 , wherein the property change comprises a change of fluid type. 
     
     
         15 . The method of  claim 13 , wherein the property change comprises a change in fluid friction. 
     
     
         16 . The method of  claim 13 , wherein the property change comprises a change in fluid temperature. 
     
     
         17 . The method of  claim 13 , wherein the property change comprises a change in fluid chemistry. 
     
     
         18 . The method of  claim 13 , wherein the property change comprises a change in a thermal property of the fluid. 
     
     
         19 . A method of tracking fluid movement along a wellbore of a well, the method comprising:
 detecting a change in density of an optical waveguide in the well; and   determining the fluid movement based on the detected density change.   
     
     
         20 . The method of  claim 19 , wherein the detecting step further comprises detecting coherent phase Rayleigh backscattering due to light transmitted through the optical waveguide. 
     
     
         21 . The method of  claim 19 , wherein the detecting step further comprises detecting Brillouin backscattering due to light transmitted through the optical waveguide. 
     
     
         22 . The method of  claim 19 , wherein the density change produces a frequency shift in light transmitted through the optical waveguide. 
     
     
         23 . The method of  claim 19 , wherein the detecting step further comprises detecting a wavelength shift for light reflected off of a Bragg grating. 
     
     
         24 . The method of  claim 19 , further comprising the step of introducing a property change into the fluid, whereby movement of the property change with the fluid generates the change in density. 
     
     
         25 . The method of  claim 24 , wherein the property change comprises a change of fluid type. 
     
     
         26 . The method of  claim 24 , wherein the property change comprises a change in fluid temperature. 
     
     
         27 . The method of  claim 24 , wherein the property change comprises a change in fluid chemistry. 
     
     
         28 . The method of  claim 24 , wherein the property change comprises a change in a thermal property of the fluid. 
     
     
         29 . A method of tracking fluid movement along a wellbore of a well, the method comprising:
 detecting a Brillouin frequency shift for light transmitted through an optical waveguide in the well; and   determining the fluid movement along the wellbore based on the detected Brillouin frequency shift.   
     
     
         30 . The method of  claim 29 , wherein the detecting step further comprises detecting Brillouin backscattering due to the light transmitted through the optical waveguide. 
     
     
         31 . The method of  claim 29 , further comprising the step of introducing a property change into the fluid, whereby movement of the property change with the fluid generates the Brillouin frequency shift. 
     
     
         32 . The method of  claim 31 , wherein the property change comprises a change of fluid type. 
     
     
         33 . The method of  claim 31 , wherein the property change comprises a change in fluid temperature. 
     
     
         34 . The method of  claim 31 , wherein the property change comprises a change in fluid chemistry. 
     
     
         35 . The method of  claim 31 , wherein the property change comprises a change in a thermal property of the fluid. 
     
     
         36 . The method of  claim 29 , wherein the Brillouin frequency shift is in response to a change in strain in the optical waveguide. 
     
     
         37 . The method of  claim 29 , wherein the Brillouin frequency shift is in response to a change in temperature of the optical waveguide.