本文關(guān)鍵詞： 地震勘探 抽取濾波器 現(xiàn)場可編程門陣列 小波閾值去噪　出處：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：地震勘探作為一種重要的物理勘探手段,在油田的開發(fā)中起著重要的作用。野外地震數(shù)據(jù)采集和地震資料的數(shù)字處理技術(shù)是地震勘探的兩個重要環(huán)節(jié)。只有得到高質(zhì)量的地震剖面圖,才能為石油勘探提供可靠的依據(jù)。實際的野外數(shù)據(jù)采集過程經(jīng)常會受到各種噪聲的干擾(規(guī)則干擾波和隨機(jī)干擾波),這些都直接影響地震解釋工作的準(zhǔn)確性。本文分析了地震勘探儀器中調(diào)制器的量化噪聲,為設(shè)備的選型提供了理論依據(jù)。針對調(diào)制器輸出的高速碼流,設(shè)計一套基于FPGA的數(shù)字抽取濾波器。研究了隨機(jī)噪聲的降噪算法,提出了一種新的降噪算法。主要內(nèi)容有:1)建立了Sigma-delta ADC調(diào)制器的線性等效模型,具體分析了一階和二階調(diào)制器的量化信噪比。推導(dǎo)了高階調(diào)制器量化信噪比和過采樣率的關(guān)系。結(jié)果表明:采用四階Sigma-delta ADC轉(zhuǎn)換器進(jìn)行采集可以實現(xiàn)120 d B以上的高精度的地震勘探技術(shù)。2)選用Xilinx公司的xc5vlx85-1ff676作為硬件開發(fā)平臺,設(shè)計了一套基于FPGA多速率降采樣數(shù)字濾波器系統(tǒng)。首先選擇合適的濾波器結(jié)構(gòu),接著使用VHDL和Verilog硬件描述語言編寫了濾波器代碼。其中設(shè)計FIR濾波器時借助了Xilinx公司的開發(fā)軟件ISE中自帶IP核,極大的提高了開發(fā)流程,并且合理的運用芯片資源。主要實現(xiàn)兩個功能:第一就是實現(xiàn)512倍的降采樣,第二就是可以濾除帶外噪聲。3)介紹了地震勘探中常見噪聲的特點,針對隨機(jī)噪聲研究了小波閾值消噪理論,提出了一種新的閾值函數(shù)消噪算法,經(jīng)過測試,能夠很好的實現(xiàn)去除隨機(jī)噪聲的效果。
[Abstract]:Seismic exploration as an important means of physical exploration, Field seismic data acquisition and digital processing of seismic data are two important links in seismic exploration. Only high-quality seismic profiles can be obtained. In order to provide reliable basis for petroleum exploration, the actual field data acquisition process is often disturbed by various kinds of noise (regular jamming wave and random interference wave), which directly affect the accuracy of seismic interpretation. In this paper, the quantization noise of modulator in seismic exploration instrument is analyzed. A set of digital decimation filter based on FPGA is designed for the high speed bitstream output of modulator, and the noise reduction algorithm of random noise is studied. A new noise reduction algorithm is proposed. The linear equivalent model of Sigma-delta ADC modulator is established. The quantization signal-to-noise ratio of first and second order modulators is analyzed in detail, and the relation between quantization signal-to-noise ratio and oversampling rate of high-order modulators is deduced. The results show that the acquisition of four-order Sigma-delta ADC converters can achieve 120dB or more. High-precision seismic exploration technology. 2) xc5vlx85-1ff676 of Xilinx Company is chosen as hardware development platform. A digital filter system based on FPGA multi-rate downsampling is designed. Then we use VHDL and Verilog hardware description language to write the filter code, in which the FIR filter is designed with the help of the IP core in the development software ISE of Xilinx Company, which greatly improves the development process. And reasonable use of chip resources. The main realization of two functions: the first is to achieve 512 times of downsampling, the second is to filter out of the band noise. 3) introduced the characteristics of common noise in seismic exploration. In this paper, wavelet threshold denoising theory is studied for random noise, and a new threshold function denoising algorithm is proposed. After testing, the effect of removing random noise can be achieved well.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.44

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本文編號：1507005