Borehole acoustic noise measurement and processing

1. A method, comprising:

generating acoustic noise by a passive source comprising at least one of a body of an acoustic tool within a borehole, a positioning device attached to the body, and a measurement device attached to the body;

receiving and recording acoustic noise data at a sampling rate and over a period during movement of the body by at least one receiver attached to the body, wherein the sampling rate is based on a first recorded acoustic frequency and the period is based on a second recorded acoustic frequency that is lower than the first recorded acoustic frequency; and

processing the recorded acoustic noise data to determine a calibration parameter of the at least one receiver.

2. The method of claim 1 , wherein the receiving and recording further comprises:

simultaneously receiving and recording the acoustic noise data from a first direction along the body and from a second direction along the body, the second direction being substantially opposite the first direction.

3. The method of claim 1 , further comprising:

increasing azimuthal pressure applied to a wall of the borehole by at least one of the positioning device and the measurement device during said receiving and recording.

4. The method of claim 1 , further comprising:

increasing an amplitude of the acoustic noise data by increasing logging speed of the down hole tool.

5. The method of claim 1 , further comprising:

increasing the amplitude of the acoustic noise data by increasing a cross-sectional area of at least one of the down hole tool, the positioning device, and the measurement device.

6. The method of claim 1 , wherein the determining comprises:

determining the calibration parameter by estimating a gain of the at least one receiver.

7. The method of claim 1 , further comprising:

calibrating the at least one receiver by applying at least one of a static gain correction parameter corresponding to the acoustic noise data obtained over a cased distance of the borehole and a dynamic gain correction parameter corresponding to the acoustic noise data obtained over an uncased distance of the borehole.

8. The method of claim 1 , wherein the processing comprises:

applying at least one of a time semblance method and a frequency semblance method to the acoustic noise data to determine the formation property.

9. The method of claim 1 , further comprising:

processing the recorded acoustic noise data using a two-sided frequency semblance method to generate two-sided frequency semblance data; and

converting two-sided frequency semblance data to one-sided frequency semblance data using an absolute value of negative slowness values.

10. The method of claim 1 , wherein

at least one of the positioning device and the measurement device is configured as a symmetrical device to excite resonant monopole modes.

11. The method of claim 1 , wherein the first recorded acoustic frequency is a highest recorded acoustic frequency and the second recorded acoustic frequency is a lowest recorded acoustic frequency.

12. The method of claim 1 , further comprising:

calculating gain for the at least one receiver without using the calibration parameter.

13. An apparatus, comprising:

a passive source configured to generate acoustic noise during movement of the passive source within a borehole, said passive source comprising at least one of a body of an acoustic tool within a borehole, a positioning device attached to the body, and a measurement device attached to the body;

at least one receiver attached to the body and configured to receive and record acoustic noise data at a sampling rate and over a period during movement of the body, wherein the sampling rate is based on a first recorded acoustic frequency and the period is based on a second recorded acoustic frequency that is lower than the first recorded acoustic frequency; and

a processor configured to process the recorded acoustic noise data to determine a calibration parameter of the at least one receiver.

14. The apparatus of claim 13 , wherein the first recorded acoustic frequency is a highest recorded acoustic frequency and the second recorded acoustic frequency is a lowest recorded acoustic frequency.

15. The apparatus of claim 13 , wherein the processor is further configured to process the recorded acoustic noise data using a two-sided frequency semblance method to generate two-sided frequency semblance data, and convert the two-sided frequency semblance data to one-sided frequency semblance data using an absolute value of negative slowness values.

16. The apparatus of claim 13 , wherein the measurement device comprises a caliper and wherein the positioning device comprises a centralizer.

17. A system, comprising:

an acoustic tool;

an apparatus attached to a tool body of the acoustic tool comprising,

a passive source configured to generate acoustic noise during movement of the passive source within a borehole, said passive source comprising at least one of the tool body, a positioning device attached to the tool body, and a measurement device attached to the tool body; and

at least one receiver configured to receive and record acoustic noise data at a sampling rate and over a period during movement of the tool body, wherein the sampling rate is based on a first recorded acoustic frequency and the period is based on a second recorded acoustic frequency that is lower than the first recorded acoustic frequency; and

a processor configured to process the recorded acoustic noise data to determine a calibration parameter of the at least one receiver.

18. The system of claim 17 , wherein the processor is further configured to process the recorded acoustic noise data using a two-sided frequency semblance method to generate two-sided frequency semblance data, and convert the two-sided frequency semblance data to one-sided frequency semblance data using an absolute value of negative slowness values.

19. The system of claim 17 , further comprising:

at least one acoustic noise isolator attached to the tool body, proximate to the at least one receiver.

20. The system of claim 17 , wherein the passive source comprises:

at least one of the positioning device and the measurement device configured as an asymmetrical device to excite resonant dipole modes.