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信号传输是随钻测井的重要组成部分,也是随钻测井进一步发展的瓶颈.针对这个问题,研究了由NovatekTM提出的基于钻杆内有线传输,钻杆间电磁耦合传输的随钻信号高速传输方法.首先,针对钻杆间的电磁耦合结构的对称性,采用了高效的数值模式匹配法对该耦合结构进行了电磁建模;然后,为了优化钻杆间耦合结构的耦合性能,利用上述的电磁建模方法对该耦合结构进行了仿真分析,分析了该耦合结构各个参数对耦合性能的影响,并得出了一些有意义的结论,该结论能够指导随钻测井信号钻杆间耦合传输的优化设计.另外,钻杆内传输线利用矩形传输线设计,设计出了50Ω特性阻抗的矩形传输线,并计算了相关损耗.最后,通过仿真和实验验证了优化设计的钻杆间耦合传输结构具有非常好的传输性能,并且仿真和实验结果符合良好.
Signal transmission is an important part of LWD and also a bottleneck for the further development of LWD. In response to this problem, the high-speed LWD signal based on wire transmission in drill pipe and electromagnetic coupling transmission between drill rods Transmission method.First, according to the symmetry of the electromagnetic coupling structure between the drill pipe and the pipe, the coupling structure is electromagnetically modeled by using an efficient numerical pattern matching method. Then, in order to optimize the coupling performance between the pipe and the pipe coupling structure, The electromagnetic modeling method is used to simulate the coupled structure. The influence of each parameter of the coupled structure on the coupling performance is analyzed and some meaningful conclusions are drawn. This conclusion can guide the coupling between the signal of the logging-while-drilling signal In addition, the transmission line inside the drill pipe is designed with a rectangular transmission line, a rectangular transmission line with a characteristic impedance of 50Ω is designed, and the related loss is calculated.Finally, the simulation and experimental results show that the optimized design of the coupling transmission structure between the drill pipe and the transmission line has Very good transmission performance, and the simulation and experimental results are in good agreement.