A Review of the Evaluation, Control, and Application Technologies for Drill String Vibrations and Shocks in Oil and Gas Well

Table 5

Drill bit vibration power spectral density.

Measure power; Spectrum downhole		Use precision downhole clock			Surface measurements of drill string motion	Measurement of bit noise at Earth’s surface
p-wave	Total waveform	Tag beginning of power spectrum			p-wave	p-wave
Torsional wave	Up-going waveform	Tag time of energetic event			Torsional wave	s-wave
Lateral wave	Down-going waveform	Limited time domain sample	Compress event as a wavelet		Acceleration	/
					Tool radial tangential axis	/
(Future compress) telemeter to surface		Telemetering to surface			Mud pressure	/
		Time/phase	Fourier transform	Wavelet decomposition	/	/
					/	/
		Alternatively, do not use precision clock			Alternatively, do not use drill string motion at surface	/