System and method for using controlled vibrations for borehole communications
A system and method are provided for producing controlled vibrations within a borehole. In one example, the system includes a movement mechanism and a vibration control mechanism. The movement mechanism is configured to use mechanical energy provided by a mechanical energy source to enable translational movement of a first surface relative to a second surface to allow the first surface to repeatedly impact the second surface to produce a plurality of vibration beats, where the vibration beats will occur whenever the mechanical energy is provided by the mechanical energy source unless the provided mechanical energy is dampened to prevent the translational movement. The vibration control mechanism is configured to selectively control an amplitude of the vibration beats to encode information therein, where the amplitude of a vibration beat is selectively controlled by dampening the provided mechanical energy to regulate the impact of the first surface and the second surface.
1. A system for producing controlled vibrations within a borehole comprising:
a movement mechanism configured to use mechanical energy provided by a mechanical energy source to enable translational movement of a first surface relative to a second surface to allow the first surface to repeatedly impact the second surface to produce a plurality of vibration beats, wherein the vibration beats will occur whenever the mechanical energy is provided by the mechanical energy source unless the provided mechanical energy is dampened to prevent the translational movement; and
a vibration control mechanism configured to selectively control an amplitude of the vibration beats to encode information therein, wherein the amplitude of a vibration beat is selectively controlled by dampening the provided mechanical energy to regulate the impact of the first surface and the second surface.
2. The system of claim 1 wherein the vibration beats occur at a fixed frequency unless the mechanical energy is dampened to prevent the translational movement.
3. The system of claim 1 wherein the vibration control mechanism is further configured to suppress the amplitude of a particular vibration beat below a detection threshold to skip that vibration beat while encoding information.
4. The system of claim 3 wherein the vibration control mechanism is configured to control the amplitude of a vibration beat to match one of a plurality of defined amplitude values.
5. The system of claim 4 wherein the defined amplitude values are bounded by a first amplitude value representing a full impact of the first and second surfaces and a second amplitude value that is below the detection threshold.
6. The system of claim 3 wherein the vibration control mechanism is further configured to reduce a frequency of the vibration beats to a desired frequency by skipping vibration beats.
7. The system of claim 1 further comprising:
a sensor positioned to detect the vibration beats; and
a controller coupled to the sensor and configured to control the vibration control mechanism based on the vibration beats detected by the sensor.
8. The system of claim 7 wherein the controller is configured to adjust the vibration control mechanism in response to changes in the amplitude of the vibration beats detected by the sensor.
9. The system of claim 7 wherein the controller is configured to adjust the vibration control mechanism in response to changes in a frequency of the vibration beats detected by the sensor.
10. A method for producing controlled vibrations within a borehole comprising:
using provided energy to cause a plurality of vibration beats to occur in a downhole tool positioned within the borehole, wherein the vibration beats are caused by a first surface striking a second surface; and
controlling an amplitude of the vibration beats to encode information therein, wherein the amplitude of a vibration beat is controlled by dampening at least a portion of the provided energy to regulate an impact force with which the first surface strikes the second surface.
11. The method of claim 10 further comprising retrieving the encoded information from the vibration beats.
12. The method of claim 10 wherein controlling the amplitude includes suppressing the amplitude of a particular vibration beat below a detection threshold to skip that vibration beat.
13. The method of claim 12 wherein controlling the amplitude of a vibration beat includes matching the vibration beat to one of a plurality of defined amplitude values.
14. The method of claim 13 wherein the defined amplitude values are bounded by a first amplitude value representing a full impact of the first and second surfaces and a second amplitude value that is below the detection threshold.
15. The method of claim 12 further comprising reducing a frequency of the vibration beats to a desired frequency by skipping vibration beats.
16. The method of claim 15 further comprising maintaining the desired frequency in response to changes in a detected frequency of the vibration beats caused by forces external to the downhole tool.
17. The method of claim 16 wherein the desired frequency is a carrier frequency that is centered on an ideal frequency that changes based on formation and bit combinations, and wherein maintaining the desired frequency includes changing the carrier frequency in response to changes in the ideal frequency.
18. The method of claim 10 further comprising maintaining a desired amplitude in response to changes in a detected amplitude of the vibration beats caused by forces external to the downhole tool.
19. The method of claim 10 further comprising passing the information to a sensor outside the borehole via the vibration beats.
20. The method of claim 19 wherein passing the information includes at least one relay positioned in the borehole and configured to amplify the vibration beats.
21. The method of claim 10 wherein the provided energy is mechanical energy.
22. The method of claim 10 further comprising converting the provided energy into mechanical energy.
23. The method of claim 10 wherein the downhole tool is part of the BHA.
24. The method of claim 10 wherein the downhole tool is separate from the BHA.
25. A system for use in a downhole drilling environment comprising:
a movement mechanism positioned in a downhole tool and configured to convert provided energy to translational movement of a first surface relative to a second surface to cause the first surface to impact the second surface to produce a plurality of vibration beats, wherein the vibration beats occur at a fixed frequency unless the provided energy is diverted to prevent the translational movement; and
a vibration control mechanism configured to divert at least a portion of the provided energy from the translational movement to selectively control an amplitude of the vibration beats to encode information therein.
26. The system of claim 25 further comprising:
a processor coupled to a sensor; and
a memory coupled to the processor and containing a plurality of instructions for execution by the processor, the instructions including:
instructions for detecting the plurality of vibration beats via the sensor; and
instructions for using the vibration control mechanism in the downhole tool to control the amplitude of the vibration beats.
27. The system of claim 26 further comprising:
instructions for detecting a change in the amplitude of the vibration beats; and
instructions for modifying an amount of the provided energy that is diverted to account for the change.
28. The system of claim 26 further comprising:
instructions for detecting a change in a frequency of the vibration beats; and
instructions for modifying an amount of the provided energy that is diverted to account for the change.
29. The system of claim 26 wherein the instructions for using the vibration control mechanism include instructions for suppressing the amplitude of a vibration beat below a detection threshold to skip that vibration beat.
30. The system of claim 29 further comprising instructions for setting the amplitude of a vibration beat to an intermediate level that is between a first amplitude value representing a full impact of the first and second surfaces and a second amplitude value that is the detection threshold.