Yang Yi, Ding Qian, Gao Yi, Chen Jia
School of Electronic Engineering, Xi'an Shiyou University, Xi'an 710065, China.
Sensors (Basel). 2023 Sep 1;23(17):7598. doi: 10.3390/s23177598.
In the process of dynamic Measurement While Drilling (MWD), the strong vibration and rapid rotation of the Bottom Hole Assembly (BHA) lead to multi-frequency and high-amplitude noise interference in the attitude measurement signal. The weak original signal and extremely low signal-to-noise ratio (SNR) are always the technical difficulties of dynamic MWD. To solve this problem, this paper uses the chaotic effect of the Duffing system, which takes the expression (- + ) as a nonlinear restoring force to detect the weak characteristic signal of downhole dynamic MWD. First of all, in order to meet the limit condition of the chaotic phase transition of the system output, the frequency value of the characteristic signal is reconstructed and transformed based on the variable scale theory. Then, in order to solve the influence of the initial phase of the characteristic signal on the detection accuracy, a detection model based on the array Duffing system is presented, and a frequency-detection scheme with all-phase coverage is given. Finally, another array Duffing system is designed for the parameter estimation of the characteristic signal. The critical value of chaotic phase transition is determined by adjusting the amplitude of the driving signal of the array Duffing system, and then the amplitude and phase parameters of the characteristic signal are synchronously estimated. The experimental results show that the proposed method can effectively extract the weak characteristic signal within the strong noise, and the SNR of the characteristic signal can be as low as -21 dB. Through the attitude calculation for the extracted characteristic signal, it can be seen that the proposed method can improve the accuracy of the inclination of the drilling tool significantly, which proves the feasibility and effectiveness of the method proposed in this paper.
在随钻动态测量（MWD）过程中，井底钻具组合（BHA）的强烈振动和快速旋转会导致姿态测量信号中出现多频高幅噪声干扰。微弱的原始信号和极低的信噪比（SNR）一直是动态MWD的技术难题。为解决这一问题，本文利用杜芬系统的混沌效应，以表达式（- + ）作为非线性恢复力来检测井下动态MWD的微弱特征信号。首先，为满足系统输出混沌相变的极限条件，基于变尺度理论对特征信号的频率值进行重构和变换。然后，为解决特征信号初相对检测精度的影响，提出一种基于阵列杜芬系统的检测模型，并给出全相位覆盖的频率检测方案。最后，设计另一个阵列杜芬系统用于特征信号的参数估计。通过调整阵列杜芬系统驱动信号的幅度来确定混沌相变的临界值，进而同步估计特征信号的幅度和相位参数。实验结果表明，该方法能在强噪声中有效提取微弱特征信号，特征信号的信噪比可低至-21 dB。对提取的特征信号进行姿态计算可知，该方法能显著提高钻具倾斜度的计算精度，证明了本文所提方法的可行性和有效性。
