High Performance MWD System Software Development Based On Qt

Surface receiving software of wireless Measurement While Drilling(MWD)system is an important part of MWD system.It is mainly used to receive pressure wave signal emitted by downhole mud pulse generator,filter noise and extract useful information from drilling fluid pulse signal.The directional parameters such as inclination,azimuth and tool face are obtained and sent to the driller indicator for display,which provides a basis for field engineers to make drilling decisions.However,drilling fluid pulse signals in the transmission process will be affected by pump noise,drill pipe noise and other different noises,resulting in the MWD system software to identify pulse signals,decoding efficiency is reduced and other problems,so it is of important theoretical and practical significance to carry out the design of MWD system software based on Qt and research on the core technology in the software.The paper content of this paper is as follows:(1)Detailed functional requirements of MWD system software were analyzed,and functional requirements of user management,parameter configuration,signal processing,data communication,graphics rendering,database and driller real-time display were defined.Function modules are divided into different roles such as drilling engineer and instrument engineer to ensure the ease of use and security of the software.(2)In order to solve the problem that drilling fluid pulse signal will be affected by pump noise,shaker noise and screw noise when it is transmitted from thousands of meters underground to the surface,Manchester code and PLM(combined code)code are adopted to encode drilling fluid pulse signal.The difference between PLM code and Manchester code is that the collected downhole data is converted into binary numbers.Then convert it into the corresponding PLM code.(3)Simulation signals with different signal-to-noise ratios were constructed for pump noise,and the FIR filtering method and wavelet filtering method were respectively analyzed.The FIR filtering algorithm could increase the processing gain with pump noise by 8d B when filtering pump noise from drilling fluid pulse signal.(4)According to the demand analysis of MWD system software,the design and implementation of MWD system software based on Qt development framework and C++programming language are carried out from different perspectives such as software development environment,software development language and software database.Finally,the static,dynamic and system testing of MWD system software is carried out.(5)A ground device based on mud pulse generator was built.According to the encoding method adopted,Manchester encoding and PLM encoding were tested experimentally.The results showed that the data encoding results were consistent with those designed in this paper under 0.5Hz and 0.8Hz transmission frequency.