【摘要】：由于地層的吸收衰減作用,實際地震記錄是一個動態(tài)衰減信號,從中提取的子波也是隨時間變化的。傳統(tǒng)的子波提取方法是基于靜態(tài)褶積模型,提取一個單一時不變的子波,這與實際情況不符。為解決地層衰減作用造成傳統(tǒng)子波提取方法提取結(jié)果不準確的問題,本文在分析研究常規(guī)分段時變子波提取方法存在不足的基礎(chǔ)上,提出了一種基于時頻譜模擬的時變混合相位子波提取方法。與分段子波提取方法相比,該方法充分展現(xiàn)了子波的時變特性,提取的子波更符合實際。針對多項式譜模擬方法在擬合子波振幅譜方面存在的局限性,本文提出了基于時頻二次譜模擬的時變子波提取方法,進一步提高了時變子波的提取精度。首先,針對常規(guī)分段時變子波提取方法不能充分還原子波時變性,且提取子波不夠準確等問題,本論文提出了基于時頻譜模擬的時變混合相位子波提取方法。首先對非平穩(wěn)地震記錄進行改進的廣義S變換,并引入時頻濾波處理,然后采用多項式譜模擬方法從處理后的地震記錄時頻譜中擬合出每一時刻的子波振幅譜,在子波相位時不變的假設(shè)條件下采用高階累積量的雙譜法重構(gòu)出子波的混合相位譜,最后將振幅譜和相位譜結(jié)合實現(xiàn)時變混合相位子波的提取。該方法突破了常規(guī)分段時變子波提取方法的不足,充分保留了子波的時變性。仿真實驗和實際地震資料處理結(jié)果表明,該方法能夠提取出更符合實際的地震子波,在地震資料處理中表現(xiàn)出明顯的應(yīng)用效果。其次,針對多項式譜模擬方法所用的擬合多項式限制了子波振幅譜的形態(tài),且求解穩(wěn)定性較差等問題,本論文進一步提出了基于時頻二次譜模擬的時變子波提取方法。該方法在基于時頻譜模擬的時變混合相位子波提取方法的基礎(chǔ)上,采用二次譜模擬代替譜模擬方法,提高了時變子波振幅譜的提取精度。仿真實驗和實際地震資料處理結(jié)果表明,該方法在充分保留子波時變性的基礎(chǔ)上能夠更精確地提取時變子波。最后,將基于時頻二次譜模擬的時變混合相位子波提取方法與分段子波提取方法進行對比,理論上分析總結(jié)了本論文所提方法在提取子波時變性和準確性方面明顯優(yōu)于分段子波提取方法。仿真實驗和實際地震資料處理結(jié)果表明,該方法突破了常規(guī)分段時變子波方法的缺陷,充分展現(xiàn)了子波的時變性,為精確提取地震子波提供了一個新途徑。
[Abstract]:Because of the absorption and attenuation of strata, the actual seismic record is a dynamic attenuation signal, and the wavelet extracted from it also varies with time. The traditional wavelet extraction method is based on the static convolution model to extract a single time-invariant wavelet which is inconsistent with the actual situation. In order to solve the problem that the traditional wavelet extraction method is inaccurate due to the formation attenuation, this paper analyzes and studies the shortcomings of the conventional piecewise time-varying wavelet extraction method. A time varying mixed phase wavelet extraction method based on time spectrum simulation is proposed. Compared with the piecewise wavelet extraction method, this method fully shows the time-varying characteristics of wavelet, and the extracted wavelet is more practical. In view of the limitation of polynomial spectral simulation in fitting wavelet amplitude spectrum, a time-varying wavelet extraction method based on time-frequency quadratic spectral simulation is proposed in this paper, which improves the accuracy of time-varying wavelet extraction. Firstly, aiming at the problem that the conventional piecewise time-varying wavelet extraction method can not fully reduce the wavelet time-variant, and the wavelet extraction is not accurate enough, a time-varying mixed phase wavelet extraction method based on time-frequency simulation is proposed in this paper. Firstly, an improved generalized S-transform is applied to the non-stationary seismic records, and a time-frequency filter is introduced, and then the wavelet amplitude spectrum at every moment is fitted from the time-frequency spectrum of the processed seismic records by the polynomial spectral simulation method. Under the assumption that the wavelet phase time is invariant, the mixed phase spectrum of the wavelet is reconstructed by using the bispectral method of higher order cumulant. Finally, the amplitude spectrum and the phase spectrum are combined to extract the time-varying mixed phase wavelet. This method breaks through the shortcomings of the conventional piecewise time-varying wavelet extraction method and fully preserves the time-varying wavelet. Simulation experiments and actual seismic data processing results show that the method can extract more practical seismic wavelet, and shows obvious application effect in seismic data processing. Secondly, the fitting polynomial used in polynomial spectral simulation method limits the shape of wavelet amplitude spectrum, and solves the problem of poor stability. In this paper, a time-varying wavelet extraction method based on time-frequency quadratic spectral simulation is proposed. Based on the time-varying mixed phase wavelet extraction method based on time-frequency simulation, the quadratic spectral simulation is used instead of the spectral simulation method to improve the accuracy of amplitude spectrum extraction of time-varying wavelet. The simulation results and the actual seismic data processing results show that the proposed method can extract time-varying wavelet more accurately on the basis of fully preserving wavelet time-variant. Finally, the time-varying mixed phase wavelet extraction method based on time-frequency quadratic spectrum simulation is compared with the piecewise wavelet extraction method. In theory, the method proposed in this paper is superior to the piecewise wavelet extraction method in terms of time variation and accuracy of wavelet extraction. The simulation results and the actual seismic data processing results show that this method breaks through the defects of the conventional piecewise time-varying wavelet method and fully shows the time-varying wavelet, which provides a new way for accurate seismic wavelet extraction.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.4

【參考文獻】

相關(guān)期刊論文 前10條

1 張漫漫;戴永壽;張亞南;丁進杰;王蓉蓉;;基于時頻域譜模擬的時變子波估計方法[J];石油物探;2014年06期

2 刁瑞;尚新民;芮擁軍;Q鞔，

本文編號：2407745