Main Frequency Band and the Reflected Sound Field in the Depth Detection of Borehole Wall Based on Microscope Technology

  • Jing Zhou
Keywords: Plasma Impulse Sound Source While Drilling, Acoustic Depth Detection, Reflected Sound Field, Microscopic Techniques.


The traditional microscope technology has the limitation of short detection distance. In order to solve this
problem, a reflective near-field optical microscope based on plasma pulse source is proposed. Firstly, based on
the basic theory of the plasma pulse sound source in the well, the influence of the drill collar on the radiated
sound field inside and outside the well is studied, and the excitation frequency range of the plasma pulse sound
source in the process of drilling is determined. Secondly, the finite element method is used to simulate the
reflection wave received by the plasma pulse source when there are reflection surfaces inside and outside the
well during the drilling process under the reflective near-field optical microscope. On this basis, the best source
distance and source excitation frequency of reflection near-field optical microscope are determined. Finally,
through the comparison of open hole wells, it is determined that the excitation frequency of the sound source
should be in the range of 2-3khz.