| Title |
A Study on Numerical Analysis Model of Acoustic Telemetry for Directional Drilling |
| DOI |
https://doi.org/10.6110/KJACR.2019.31.2.091 |
| Keywords |
방향성 시추 ; 원격 음파통신 ; 음파 방정식 ; 압전구동기 ; 드릴 스트링 Directional drilling ; Acoustic telemetry ; Wave equation ; Piezo actuator ; Drill string |
| Abstract |
This paper presents a method to model and simulate the propagation properties of the acoustic wave in periodic pipelines. First, an ideal model of pipeline and its dispersion equations of acoustic waves are constructed and described in detail in order to implement this method. Subsequently, the classical finite difference method is applied to determine the boundary conditions of the pipelines. To investigate dynamic characteristics of periodical pipelines, an impulse response is simulated. From the simulations, stop and pass bands are identified. For telecommunication, a packet of bits is transmitted with chirps signal whose center frequency is 700 Hz and the whole band width is 50 Hz and its response on the surface is simulated. By FFT analysis, it is found that communication by chirps signal is feasible with high baud rate. And also it is noticed that if the chirp's center frequency and band width are poorly chosen, it ends up with building standing waves whose presence makes decoding impossible. The structure of the model leaves room for further improvement by adding a viscous term and various point sources of noises |