Analysis of the Factors Affecting the Decoding Success Rate of High rate Shear Valve Pulser

The "Xuanji" system is a revolutionary drilling technology independently developed by China Oilfield Services Limited(COSL). It is composed of two major technologies, namely rotary steering drilling "Welleader" and logging while drilling "Drilog", and has currently achieved large-scale application. While the High rate Shear Valve Pulser(HSVP), as a crucial component of the "Xuanji" system, can reach a maximum transmission rate of 20 bps under actual drilling conditions. The high-rate mud pulser utilizes mud pulses for signal transmission and can upload downhole logging data, wellbore trajectory, and engineering parameters to the surface system in real time. The surface data acquisition and demodulation system parses the received mud pulse signals to realize real-time communication between downhole instruments and the surface system. However, channel transmission characteristics such as acquisition noise and pump noise can interfere with the signal quality and affect the decoding success rate of surface signals. This paper analyzes the sources of noise, discusses the influences of channel characteristics, pump noise, acquisition noise, bottom hole assembly(BHA), drilling engineering parameters, mud parameters, and signal processing parameters on the decoding success rate, and adopts corresponding methods to handle the noise that affects the decoding success rate. This has greatly enhanced the decoding success rate of the signals and is of great significance for improving the real-time demodulation effect of high-speed mud pulse data transmission.