摘要
随钻测量系统中钻井液正脉冲的数据传输速率较低,通过分析正脉冲实测数据的信号特性,并根据连续压力波信号的产生和传输过程,建立了具有高数据传输速率的钻井液连续压力波信号的数学模型。由于井口连续波信号中有用信号较弱,且噪声的低频部分与有用信号混杂在一起,正脉冲的小波处理方法无法去除低频噪声。为提取微弱的连续波信号,首次将经验模态分解算法应用到钻井信号中,提出了一套基于平稳小波变换和经验模态分解的联合去噪方案,并设计出了详细的实现过程,该方案充分发挥了平稳小波的去噪优势和经验模态的分解优势,能够有效去除微弱连续波信号中混有的低频和高频噪声。通过仿真测试,发现该联合方案相对平稳小波具有更好的去噪效果和可靠性。
The data transmission rate of the positive pulse in drilling fluid of MWD system is lower, by analyzing the signal characteristics of the actually measured data in positive pulse, and in accordance with the generation and transmission process of continuous pressure wave signals, the mathematical model of the drilling fluid signals of the continuous pressure waves was established,which had a high data transmission rate. Because the useful signals are weak in wellhead continuous wave signals and the low-frequency part of the noise is mixed with the useful signals, the wavelet processing method of positive pulse is unable to remove low-frequency noise.In order to extract weak continuous wave signals, for the first time, the decomposition algorithm of the empirical mode was applied to drilling signals, a set of joint denoising program was provided on the basis of stationary wavelet transform and empirical mode decomposition, and a detailed implementation process was designed, the program made full use of the denoising advantages of stationary wavelet and decomposition advantages of the empirical mode. It can directly and effectively remove low-frequency and high-frequency noise mixed in the weak continuous wave signals. From simulating tests, we found that the joint program had better denoising effects and reliability to stationary wavelet.
出处
《录井工程》
2013年第1期31-36,87,共6页
Mud Logging Engineering
基金
国家自然科学基金(60975009)
关键词
随钻测量
连续压力波
平稳小波变换
经验模态分解
MWD, continuous pressure wave, stationary wavelet transform, decomposition of empirical mode
