A telemetry drill string system consists of a string of wired drill pipes, and high-frequency signals pass the adjacent drill pipes through inductive couplers. Such a system is used to upload downhole information at high data transmission rates for measurements while drilling (MWD). Since the signal energy attenuates greatly in the system, many repeaters must be provided to ensure signal transmission. A reduction in the signal transmission in a telemetry drill string can extend the relay distance and improve the reliability of the transmission system. In this study, the transmission characteristic of the rod of the wired drill pipe is studied using transmission line theory, and the transmission characteristic of the inductive coupler is studied using high-frequency circuit theory. Using impedance matching between the transmission line of the rod and the inductive coupler, external impedance compensation elements, including a capacitor and a resistor, are recommended, and the electromagnetic parameters of the wired drill pipe are determined. Based on the determined electromagnetic parameters, certain changes in the external impedance compensation capacitance and resistance can lead to impedance mismatch between the transmission line and the inductive coupler. This will generate a reflected signal at the transmission line, and the vector superposes with the transmitted signal. The terminal reflection coefficient of the transmission line is controlled by increasing the compensation resistance value to enhance the signal amplitude, which can compensate the transmission loss when passing through the inductive coupler to a certain extent. Thus, the signal transmission capability of the telemetry drill string can be improved, allowing for long-distance signal transmission or drastically extending the relay distance, while maintaining a certain channel bandwidth.

中文翻译：

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使用传输线终端处的反射信号提高遥测钻柱的信号传输能力

遥测钻柱系统由一排有线钻管组成，高频信号通过感应耦合器传递相邻的钻管。这种系统用于以高数据传输速率上传井下信息，以进行随钻测量（MWD）。由于信号能量在系统中大大衰减，因此必须提供许多中继器以确保信号传输。遥测钻柱中信号传输的减少可以延长中继距离并提高传输系统的可靠性。在这项研究中，使用传输线理论研究了有线钻杆的杆的传输特性，并使用高频电路理论研究了感应耦合器的传输特性。通过使用杆的传输线和感应耦合器之间的阻抗匹配，建议使用包括电容器和电阻器的外部阻抗补偿元件，并确定有线钻杆的电磁参数。根据确定的电磁参数，外部阻抗补偿电容和电阻的某些变化会导致传输线和电感耦合器之间的阻抗不匹配。这将在传输线上生成反射信号，并且矢量与传输信号重叠。通过增加补偿电阻值以提高信号幅度来控制传输线的终端反射系数，可以在一定程度上补偿通过电感耦合器时的传输损耗。因此，可以提高遥测钻柱的信号传输能力，允许长距离信号传输或极大地扩展中继距离，同时保持一定的信道带宽。