發(fā)布時間：2018-02-27 23:01

  本文關鍵詞： 逐減隨機震源采樣法 頻率域 二維黏滯聲波方程 全波形反演 無記憶擬牛頓算法 L-BFGS　出處：《吉林大學學報(地球科學版)》2016年06期 　論文類型：期刊論文

【摘要】：全波形反演方法利用疊前地震波場的運動學和動力學信息重建地下速度結構,具有揭示復雜地質背景下構造與巖性細節(jié)信息的潛力。然而,巨大的計算量是阻礙其發(fā)展的一個瓶頸問題。為此,研究者們提出了震源編碼技術來減少計算量,但是此方法在模型更新過程中會引進隨機串擾噪聲,降低反演結果準確性。所以,在保證計算精度的情況下,本文提出了采用逐減隨機震源采樣的方法來高效計算全波形反演問題。筆者將此方法應用于頻率域二維黏滯聲波波動方程全波形反演,開始了在頻率域進行隨機震源采樣類方法的研究,計算過程中共使用了依次增大的8個頻率段;并應用Overthrust模型來驗證此類隨機震源采樣法的正確性。實驗結果表明:基于逐減隨機震源采樣法的反演結果與實際Overthrust模型的擬合誤差為0.065 65,而應用基于全部震源的全波形反演方法得到的反演結果與實際Overthrust模型的擬合誤差為0.064 64,兩者差別不大;但計算用時由740min減少到291.2min,即計算效率提高了2.54倍。為了更好地確定方法的有效性,將其應用于Marmousi模型進行試算。模型試算結果表明:基于逐減隨機震源和基于全部震源得到的反演結果與實際Marmousi模型的擬合誤差分別為0.080 12和0.078 97,相差不大;但計算用時由1 218.9min減少到274.4min,計算效率提高了4.44倍。綜上,在保證反演精度的情況下,基于逐減隨機震源采樣法的頻率域全波形反演方法大大減少了計算量,具有不可替代的計算優(yōu)勢,并且沒有引進隨機串擾噪聲。
[Abstract]:The full waveform inversion method uses the kinematics and dynamics information of pre-stack seismic wave field to reconstruct the underground velocity structure, which has the potential to reveal the details of structure and lithology in complex geological background. However, The huge amount of computation is a bottleneck problem that hinders its development. For this reason, the researchers put forward the source coding technique to reduce the computation load, but this method will introduce random crosstalk noise in the process of model updating. Reduce the accuracy of the inversion results. So, while ensuring the accuracy of the calculation, In this paper, a method of reducing random source sampling is proposed to efficiently calculate the full waveform inversion problem, which is applied to the full waveform inversion of two-dimensional viscous acoustic wave equation in frequency domain. The method of random source sampling is studied in frequency domain. Eight frequency bands are used in the calculation. The Overthrust model is used to verify the correctness of this random source sampling method. The experimental results show that the fitting error between the inversion result based on the subtractive random source sampling method and the actual Overthrust model is 0.065 65, while the application of the method based on the full source. The fitting error between the full waveform inversion method and the actual Overthrust model is 0.064 64, the difference between them is not significant. However, the computational time was reduced from 740min to 291.2 mins, that is, the computational efficiency was increased 2.54 times. The results show that the fitting errors of the inversion results based on the decreasing random source and all the sources are 0.08012 and 0.078 97, respectively, compared with the actual Marmousi model. However, the calculation time is reduced from 1 218.9 min to 274.4 min, and the computational efficiency is increased by 4.44 times. In summary, under the condition of guaranteeing the inversion accuracy, the frequency domain full waveform inversion method based on the subtractive random source sampling method greatly reduces the calculation amount. It has irreplaceable computational advantages and no random crosstalk noise is introduced.
【作者單位】： 吉林大學地球探測科學與技術學院;
【基金】：國家自然科學基金重點項目(41430322) 國家重點基礎研究發(fā)展計劃(“973”計劃)項目(2013CB429805)~~
【分類號】：P631.4
，

本文編號：1544691