|
|
|
| The characteristics of acoustic wave propagation along the non-periodic ideal drill strings |
| ZHANG Mei-ling; YAN Xiang-hong; LIU Wen-li; SU Yuan-da; CHEN Xue-lian; LU Bin |
| College of physics science and technology in China University of petroleum, Dongying ,Shandong 257061,China |
|
|
|
|
Abstract The non-periodic structure’s dispersion equation and the sound attenuation equation have been given based on the one-dimensional model of sound propagation. The relationship between the geometry parameters of drill strings with the dispersion characteristic as well as the attenuation characteristic is investigated numerically for a non-periodic drill string system, and the FEM software- ANSYS were used to confirm the theory results. The results shows that the dispersion characteristic of a non-periodic drill string system is identical with the result from of 'and' operation of dispersion characteristic of multiple periodic structure systems．The non-periodic structure’ passband is narrow while the stopband is wide, If the sound wave frequency were in the stopband, the acoustic attenuation would be larger than it in passband.
|
|
Received: 30 July 2010
|
|
Corresponding Authors:
ZHANG Mei-ling
|
|
|
|
|
|
|
2012, Vol. 31 
