Measuring frequency-dependent acoustic attenuation
Methods and systems for frequency-dependent fluid attenuation measurement are provided. In certain embodiments, the methods comprise: generating one or more reference acoustic signals within a reference fluid; receiving one or more reference acoustic signal reflections; determining a frequency-dependent response function based, at least in part, on the one or more reference acoustic signal reflections; generating one or more sample acoustic signals within a sample fluid; receiving one or more sample acoustic signal reflections; and determining a frequency-dependent attenuation function of the sample fluid based, at least in part, on the one or more sample acoustic signal reflections and the frequency-dependent response function.
1. A method comprising:
generating one or more reference acoustic signals within a reference fluid;
receiving one or more reference acoustic signal reflections;
determining a frequency-dependent response function based, at least in part, on the one or more reference acoustic signal reflections;
generating one or more sample acoustic signals within a sample fluid;
receiving one or more sample acoustic signal reflections; and
determining a frequency-dependent attenuation function of the sample fluid based, at least in part, on the one or more sample acoustic signal reflections and the frequency-dependent response function.
2. The method of claim 1 wherein at least one of the one or more reference acoustic signals and the one or more sample acoustic signals comprise a plurality of pure tone pulses.
3. The method of claim 1 wherein at least one of the one or more reference acoustic signals and the one or more sample acoustic signals comprise a tuned pulse.
4. The method of claim 1 wherein at least one of the one or more reference acoustic signals and the one or more sample acoustic signals comprise a broadband impulse.
5. The method of claim 1 , wherein determining a frequency-dependent attenuation function of the sample fluid comprises dividing the frequency-dependent response function out of the one or more sample acoustic signal reflections.
6. The method of claim 1 , wherein determining a frequency-dependent attenuation function comprises fitting attenuation response data to a model.
7. The method of claim 1 , wherein the one or more reference acoustic signals travel a known standoff distance.
8. The method of claim 1 , wherein the sample fluid is a wellbore treatment fluid.
9. The method of claim 1 , wherein the one or more sample acoustic signals are generated by a downhole tool disposed in a wellbore, wherein the downhole tool comprises a transducer.
10. The method of claim 9 , wherein the downhole tool comprises a rotating head to which the transducer is coupled.
11. The method of claim 10 , the one or more sample acoustic signals reflect off a portion of the wellbore.
12. The method of claim 9 , wherein the downhole tool comprises a mud cell.
13. The method of claim 12 , wherein the one or more sample acoustic signals reflect off an acoustic target within the mud cell.