摘要
为了提取出无线随钻测量中的钻井液脉冲信号并正确识别，对钻井液脉冲信号有效提取算法进行了研究。采用形态滤波算法来提取钻井液脉冲信号，运用膨胀与腐蚀运算来设计信号形态滤波器；在此基础上，根据曼彻斯特编码井下信号同步的特点，提出了一种基于周期内信号等份分割来精确分辨钻井液脉冲信号开始时刻的算法；采用模式相似度的波形识别算法，用来识别钻井液脉冲信号。仿真分析表明，运用形态滤波算法能有效提取出微弱的钻井液脉冲信号，能够提取去信噪比为20dB的钻井液脉冲信号；运用模式相似度波形识别算法能有效对曼彻斯特编码的钻井液脉冲信号进行识别，能够对0.0345～0.0690MPa的微弱脉冲信号进行识别，识别出来的比特流数据分析表明，采用该识别算法的误码率低于1.5％。研究结果表明，形态滤波算法和模式相似度波形识别算法能精确地提取和识别出钻井液脉冲信号，提高解码正确率，满足工程应用的要求。
In order to extract the useful weak pulse signal in drilling fluids and recognize it while log-ging during the implementation of MWD ,an effective extraction and algorithm for pulse signal was stud-ied .The morphological filtering algorithm has been used to extract the pulse signal from drilling fluids ,u-sing the expansion and corrosion a lgorithm to design the signal morphology filter .According to the syn-chronous characteristics of the downhole signal with Manchester encoding ,an algorithm based on a signal equal segmentation in cycle to recognize the time when starting showing pulse signal in drilling fluids accu-rately was presented .A waveform recognition algorithm with a pattern similarity was used to identify the pulse signal in drilling fluids .Simulation results showed that a morphological filtering algorithm can effec-tively extract the pulse signal from drilling fluids ,the pulse signal that has signal-to-noise ratio of 20 dB can be extracted .The application of pattern-similarity waveform recognition algorithm can recognize effectively the pulse signal in drilling fluids based on Manchester encoding ,the recognition range of weak pulse signal from 0.034 5 M Pa to 0.069 0 M Pa .According to the statistics and analysis of bit stream data ,the identifi-cation algorithm can make the error rate less than 1.5% .The results showed that a morphological filtering al-gorithm and a pattern-similarity waveform recognition algorithm can accurately extract and recognize the pulse sig-nal in drilling fluids ,improve decoding accuracy ,and meet the requirements of engineering applications .
出处
《石油钻探技术》
CAS
CSCD
北大核心
2014年第5期85-89,共5页
Petroleum Drilling Techniques
基金
湖南省教育厅科研一般项目"MWD中泥浆脉冲信号提取与识别技术研究"(编号:14C0515)
湖南理工学院科研资助项目"微弱泥浆脉冲信号的多尺度非线性分析及应用"(编号:2014Y30)联合资助
关键词
钻井液
脉冲信号
形态滤波
相似度
drilling fluids
pulse signal
morphological filtering
pattern similarity
