US 12,241,368 B2
Synchronization method for an MWD mud pulse telemetry system
Jing Ou, Beijing (CN); Jiansheng Du, Beijing (CN); Wenxiu Zhang, Beijing (CN); Xinzhen He, Beijing (CN); Xiaolong Li, Beijing (CN); and Yuliang Wang, Beijing (CN)
Assigned to INSTITUTE OF GEOLOGY AND GEOPHYSICS, CHINESE ACADEMY OF SCIENCES, Beijing (CN)
Appl. No. 18/035,294
Filed by Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing (CN)
PCT Filed Dec. 28, 2020, PCT No. PCT/CN2020/139834
§ 371(c)(1), (2) Date May 4, 2023,
PCT Pub. No. WO2022/126716, PCT Pub. Date Jun. 23, 2022.
Claims priority of application No. 202011513488.X (CN), filed on Dec. 18, 2020.
Prior Publication US 2023/0407742 A1, Dec. 21, 2023
Int. Cl. E21B 47/20 (2012.01)
CPC E21B 47/20 (2020.05) 8 Claims
OG exemplary drawing
 
1. A synchronization method for a measurement while drilling (MWD) mud pulse telemetry system, characterized by comprising steps below:
determining a synchronous training sequence on a basis of a frame structure of downhole sent data;
constructing a correlation between a downhole sending synchronous training sequence waveform and an uphole synchronous training sequence local waveform by means of an irrelevance of a trigonometric function;
performing, uphole, correlation calculation on a received synchronous training sequence waveform which is subjected to a first modulation and the synchronous training sequence local waveform which is subjected to a second modulation, so as to obtain a correlation curve; and
finding a synchronous position according to a peak of the correlation curve.