發(fā)布時間：2018-07-05 11:10

  本文選題：小波濾波 + 相干體算法��； 參考：《吉林大學(xué)》2015年碩士論文

【摘要】：在大規(guī)模工業(yè)化的今天，社會對石油的需求空前強烈，對石油資源的勘探開發(fā)已經(jīng)被提到了一個空前的重要地位。隨著勘探工作的不斷深入，，各種復(fù)雜的地質(zhì)情況都會遇到，這就對勘探技術(shù)提出了更高的要求。一種比較節(jié)約的勘探方法就是采用人工地震的方式獲取地層反射的地震數(shù)據(jù)，通過對地震數(shù)據(jù)的解釋來勘探地下的地質(zhì)結(jié)構(gòu)。地層中的斷層結(jié)構(gòu)對于石油勘探具有重大意義，通過對斷層的分析，地質(zhì)勘探人員可以得出地下的油藏情況。 相干體技術(shù)是當(dāng)前對地震數(shù)據(jù)的斷層解釋的有效方法。它通過計算相鄰的若干地震道的相似程度，來檢測地震波同相軸的不連續(xù)性。這些計算得到的相似性的數(shù)值，按照他們的空間、時間排列，組合成了相干體數(shù)據(jù)。相干體消除了振幅波動給斷層識別帶來的不便，突出了斷層給相鄰道數(shù)據(jù)帶來的不連續(xù)特征。對于識別斷層具有極大的幫助。 針對地震數(shù)據(jù)的特點，和相干體技術(shù)的優(yōu)點，本文從改善相干體源數(shù)據(jù)的角度入手，進(jìn)行了相關(guān)的研究工作。 研究地震數(shù)據(jù)的特點，發(fā)現(xiàn)地震數(shù)據(jù)是一種含有正負(fù)值，并且均值為零的時間振幅波。這些地震波在相鄰數(shù)據(jù)道的相似程度，決定了相干體值的大小。將地震道上的數(shù)據(jù)的相鄰點做差，就可以得到一個同原數(shù)據(jù)波的相位近似相差 的新的數(shù)據(jù)波。對由這種數(shù)據(jù)波組成的數(shù)據(jù)體進(jìn)行相干體計算，可以得到與原來的地震數(shù)據(jù)相干體類似，但可以顯示更多地質(zhì)結(jié)構(gòu)細(xì)節(jié)的相干體。 使用一維小波對地震數(shù)據(jù)進(jìn)行小波分解，剔除高頻部分，得到更加平滑的地震道數(shù)據(jù)波形。這樣的地震數(shù)據(jù)，在相鄰道的相似性上，得到了提高，從而提高了相干體的質(zhì)量。之所以對分解的地震數(shù)據(jù)直接剔除高頻部分，而不是像使用小波處理圖像那樣進(jìn)行閾值濾波，就是考慮到地震數(shù)據(jù)是波動性的數(shù)據(jù)，在過零點附近的波動變化快，若果采用閾值濾波就會產(chǎn)生階梯效果。還有就是直接剔除高頻部分，計算速度更高。 對地震數(shù)據(jù)進(jìn)行三維小波濾波，增強數(shù)據(jù)道之間的橫向相似性，消除地震道間的噪聲干擾。研究三維的地震數(shù)據(jù)小波濾波的時候，使用了兩種不同的濾波方法，發(fā)現(xiàn)這兩種方法各有優(yōu)缺點。一種是，分別在三個方向上分別使用小波濾波，并進(jìn)行重構(gòu)。得到三個方向的濾波結(jié)果，再求其平均值作為最終的濾波結(jié)果。另外一種方法就是，傳統(tǒng)的可分離變量的三維小波濾波。在剔除三個方向小波變換的得到的高頻部分之后，再進(jìn)行重構(gòu)，得到濾波后的數(shù)據(jù)。這兩種濾波方法都對于在此基礎(chǔ)上計算的相干體又增強的作用。第一種方法得到的地震道數(shù)據(jù)與原始地震數(shù)據(jù)變化不大，所以對地質(zhì)體中的較小的結(jié)構(gòu)保留較好，但同時也保留了相應(yīng)數(shù)量的噪聲。第二種方法很好地提高了相鄰道的相似性，對于較大的斷層結(jié)構(gòu)的保留也非常好，很適合用于識別大斷層。 鑒于本文在試驗的時候選取了不同的地震數(shù)據(jù)，應(yīng)用了不同的方法。地震數(shù)據(jù)A，適合使用一維的小波濾波方法，而地震數(shù)據(jù)體B適合使用三維的小波濾波方法。本文并沒有給出一個普適的方法，只是給出了一些可供選擇地方法。
[Abstract]:In today's large-scale industrialization, the demand for oil is unprecedentedly strong. The exploration and development of petroleum resources has been mentioned as an unprecedented important position. With the deepening of exploration work, all kinds of complex geological conditions will be encountered, which puts forward higher requirements for exploration technology. A relatively economical exploration method. It is to obtain the seismic data reflected by the artificial earthquake, and to explore the geological structure of the underground by interpreting the seismic data. The fault structure in the stratum is of great significance to the oil exploration. By analyzing the fault, the geological Explorer can get the oil reservoir under the ground.
Coherent body technique is an effective method of fault interpretation of seismic data. By calculating the similarity of several adjacent seismic channels, the discontinuity of the phase axis of seismic waves is detected. These calculated similarity values, according to their space and time arrangement, the coherent body data are synthesized. The coherent body eliminates the amplitude wave. The inconvenience caused by dynamic fault recognition highlights the discontinuity characteristics brought by faults to adjacent road data, which is of great help in identifying faults.
In view of the characteristics of seismic data and the advantages of coherence cube technology, this paper has done some related research work from the perspective of improving coherent source data.
The characteristics of seismic data are studied. It is found that the seismic data is a time amplitude wave with positive and negative values and the mean value is zero. The magnitude of the coherent body value is determined by the similarity of these seismic waves in the adjacent data channels. The difference of the adjacent points on the seismic data can be obtained by the approximate phase difference between the same data wave.
A new data wave. The coherence body calculation of the data body composed of this data wave can be similar to the original seismic data coherent body, but can display more details of the geological structure.
We use one dimensional wavelet to decompose the seismic data, eliminate the high frequency part, and get a more smooth waveform of the seismic trace data. This seismic data is improved on the similarity of adjacent channels, thus improving the quality of the coherent body. The reason why the number of decomposed earthquakes is eliminated directly, rather than the use of the wavelet In the same way, the threshold filtering means that the seismic data is fluctuant, and the fluctuation near the zero crossing is fast. If the threshold filter is used, the step effect will be produced.
The seismic data is filtered by three dimensional wavelet, and the transverse similarity between the data channels is enhanced and the noise interference between the seismic channels is eliminated. When the wavelet filtering of 3D seismic data is studied, two different filtering methods are used and the advantages and disadvantages of the two methods are found. One is to use wavelet filtering respectively in three directions, respectively. The filtering results of three directions are obtained, and the average value of the filter is obtained as the final filtering result. The other method is the three-dimensional wavelet filtering of the traditional separable variables. After eliminating the high frequency part of the three direction wavelet transform, the reconfiguration and the filtered data are obtained. The two filtering methods are all correct. The first method has little change of the seismic data and the original seismic data, so the smaller structure in the geological body is well preserved, but the corresponding number of noise is retained at the same time. The second methods can improve the similarity of the adjacent channels well, for the larger fault junction. The structure is also well preserved and suitable for identifying large faults.
In view of the selection of different seismic data in this paper, different methods are applied. The seismic data A is suitable for using one dimensional wavelet filtering method, and the seismic data body B is suitable for the use of three-dimensional wavelet filtering. This paper does not give a universal method, only a few alternative methods are given.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.44

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