微弱信号检测技术在侧向测井中的应用研究

发布时间：2018-01-22 00:32

本文关键词： 侧向测井信号预处理数字相敏检波小波去噪　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着探测深度的不断增加,钻井液侵入地层特征越来越复杂,双侧向测井仪仅能提供深浅两种模式下的视电阻率曲线,无法满足复杂油气评价的需求,研制多探测模式的新型阵列侧向测井仪势在必行。根据数值模拟结果,井下监督电极上探测到的最小电压幅度只有百纳伏级别,且动态范围大,为了提高检测的精度,需深入研究微弱信号检测技术在侧向测井中的应用。本文针对侧向测井中的阵列侧向测井微弱信号检测技术进行了研究,通过研究阵列侧向测井工作模式,在分析侧向测井中信号的特点的基础上,提出了相应检测系统设计方案,包括硬件设计部分与数字信号处理关键技术的确定。硬件部分首先确定设计参数指标,重点部分为设计信号预处理电路,包括设计低噪声前置放大器,选取滤波器的结构及参数,并进行Multisim仿真分析。数字信号处理重点在于方案的选取。在Matlab仿真环境下,对比数字滤波器与小波变换的去噪结果发现后者效果更好,对比FFT变换算法与数字相敏检波两种不同算法检测结果发现后者检测准确度更高,误差更小,最后通过对比分析小波去噪结合数字相敏检波与直接数字相敏检波检测的相对误差,从时效性与精简设计考虑确定选用直接数字相敏检波检测方案,并设计了数字信号处理流程图,最后对信号预处理印制电路板进行了功能测试实验,实验结果达到预定设计指标。
[Abstract]:With the increasing depth, drilling fluid invasion formation characteristics become more and more complex, the dual laterolog instrument can only provide the depth of apparent resistivity curves under the two modes, can not meet the complex evaluation of oil and gas demand, development of a new type of array laterolog tool potential multi detection mode is necessary. According to the results of numerical simulation, the minimum voltage the amplitude monitor electrode to detect only bynano volt level, and high dynamic range, in order to improve the detection accuracy, the application needs further study of weak signal detection technology in lateral logging in.
This paper studies the weak signal detection technology of array laterolog in lateral logging was carried out, through the study of array lateral logging mode, based on analyzing the characteristics of the signal in the lateral logging, put forward corresponding design detection system, including hardware design and key technology of digital signal processing. The hardware part design parameter the key part is the design of indicators, signal pretreatment circuit, including the design of low noise preamplifier, select the filter structure and parameters, and analysis of Multisim simulation. Digital signal processing is the key for selection. In the Matlab simulation environment, comparison of digital filter and wavelet transform denoising results and find that the latter effect is better, compared to FFT transform algorithm and digital phase sensitive detection of two kinds of algorithm tests found that the latter detection accuracy, small error, finally Through the comparative analysis of wavelet denoising based on digital phase sensitive detection and direct digital phase sensitive detection from relative error detection, timeliness and streamline design considerations determine the selection of direct digital phase sensitive detection scheme, and the design of the digital signal processing flow chart, at the end of the signal preprocessing of printed circuit board of the function test, the experimental results met the design index.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.81

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