多频阵列感应的仿真与实验装置设计

发布时间：2018-09-06 13:15

【摘要】：多频阵列感应测井信号的发射和接收是仪器设计中的核心部分,本论文研究阵列感应测井仪多频信号的发射与接收方法。首先用Lab VIEW软件仿真阵列感应测井仪多频信号发射与接收的基本原理与测试可行性,然后进行硬件设计与实现,开发出可以进行多频信号发射与接收实验研究的实验装置,具体内容和成果主要体现在以下几方面:第一部分主要研究阵列感应测井仪多频信号的发射与接收机理。首先推导方波信号的傅立叶展开公式,证明方波与奇次谐波之间的分解和合成是可逆的。然后利用Lab VIEW软件仿真无噪声时基于8个奇次谐波信号的阵列感应仪的多频信号发射与接收特性。结果表明,8个谐波合成发射近似方波,而接收不是方波,但具有提取方波信号的特征信息。最后研宄含噪声时的发射和接收特性。通过仿真表明将堆栈技术和傅立叶变换结合起来可以有效消除接收信号中的各种随机噪声。这些成果为实际阵列感应测井仪多频发射与接收传感器电路的设计与实现提供了理论依据。第二部分设计了阵列感应测井仪实验装置硬件电路,包括发射、线圈系和接收电路三部分。发射电路采用DSP处理器产生高低电平,结合编写的占空比为50%、频率l OKHz的PWM脉宽调制波形程序,生成基频为l OKHz的方波信号。发射电路由DSP芯片及其外围电路组成。制作了实验室可以实现的典型三线圈系。采用2812 DSP为主控芯片构成一个多通道数据采集接收电路。通过调理滤波电路解决信号放大滤波问题,利用高精度数据懫集电路实现了信号的采集功能。接收电路主要包含电源滤波电路、信号调理电路、外围电路、串口电路、外部存储器电路等。最终根据PCB原理图焊接完成测试电路板。第三部分完成了阵列感应测井仪实验装置的软件设计,包括DSP采集程序、校正方法、上位机软件等。设计基于DSP采集程序,进行系统模块配置,包括时钟、相应寄存器、外部端口、事件管理器、ADC懫集模块等。通过比较分析传统两点一线校正原理和最小二乘法校正原理各优越性,确定应用最小二乘法校正方法来提高采集精度。采用VB语言^u发上位机软件,它主要实现了串口通信、命令控制、显示波形、数据保存和数据处理等功能。信号被接收后DSP将采集到的数据送给上位机在其界面显示。完成系统调试工作后,测得数据结果表明设计满足要求。^u发出的多频阵列感应测井发射与接收实验装置,可以研宄多频信号的发射和接收过程、多频方法消除测量噪声的机理。
[Abstract]:The transmitting and receiving of multi-frequency array induction logging signal is the core part of the instrument design. In this paper, the method of transmitting and receiving multi-frequency signal of array induction logging tool is studied. The basic principle and test feasibility of transmitting and receiving multi-frequency signals of array induction logging tools are simulated with Lab VIEW software. Then the hardware design and implementation are carried out, and an experimental device is developed for the experimental study of multi-frequency signals. The main contents and achievements are as follows: the first part mainly studies the multi-frequency signal transmission and receiver theory of the array induction logging tool. Firstly, the Fourier expansion formula of square wave signal is derived. It is proved that the decomposition and synthesis between square wave and odd harmonic wave are reversible. Then Lab VIEW software is used to simulate the multi-frequency signal transmitting and receiving characteristics of the array sensor based on eight odd harmonic signals without noise. The results show that eight harmonic synthesizers transmit approximately square waves, but the reception is not square waves, but it has the characteristic information of extracting square wave signals. Finally, the transmitting and receiving characteristics of noise are studied. The simulation results show that the stack technique and Fourier transform can effectively eliminate the random noise in the received signal. These results provide a theoretical basis for the design and implementation of multi-frequency transmitter and receiver sensors for practical array induction logging tools. In the second part, the hardware circuit of array induction logging instrument is designed, which includes three parts: transmitting, coil system and receiving circuit. The transmitting circuit uses DSP processor to produce high and low level, combined with the program of PWM pulse width modulation waveform with duty cycle of 50 and frequency l OKHz to generate square wave signal with base frequency of l OKHz. The transmitting circuit is composed of DSP chip and its peripheral circuit. A typical three-coil system can be realized in the laboratory. A multi-channel data acquisition and receiving circuit is constructed with 2812 DSP as the main control chip. The problem of signal amplification and filtering is solved by adjusting the filter circuit, and the signal acquisition function is realized by using the high precision data collection circuit. The receiving circuit includes power filter circuit, signal conditioning circuit, peripheral circuit, serial circuit, external memory circuit and so on. Finally, the test circuit board is welded according to the PCB schematic diagram. In the third part, the software design of the array induction logging tool is completed, including the DSP acquisition program, the correction method, the host computer software and so on. The system module configuration is designed based on DSP acquisition program, including clock, register, external port, event manager, ADC-set module and so on. By comparing and analyzing the advantages of the traditional two point one line correction principle and the least square correction principle, it is determined that the least square correction method is used to improve the acquisition accuracy. The VB language is used to send the upper computer software, which mainly realizes the functions of serial communication, command control, waveform display, data saving and data processing. After the signal is received, DSP sends the collected data to the host computer to display on its interface. After the debugging of the system, the data obtained show that the design meets the requirements. The experimental device of multi-frequency array induction logging and receiving can be used to study the process of transmitting and receiving multi-frequency signals, and the mechanism of eliminating measurement noise by multi-frequency method can be studied.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.83

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