本文選題：瞬變電磁三維正反演　切入點(diǎn)：偽譜法　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：20世紀(jì)80年代后,瞬變電磁法(TEM)迅速地發(fā)展,現(xiàn)已廣泛應(yīng)用于油氣勘探、工程勘查、礦產(chǎn)勘查等眾多方面。但目前瞬變電磁法二、三維正反演方法技術(shù)還處于探索研究階段,離實(shí)用化還有很大距離。因此,本文圍繞瞬變電磁法三維正反演問題開展研究。本文應(yīng)用偽譜法(PSM)計(jì)算和分析全空間介質(zhì)中高阻體和低阻體的響應(yīng)特征,計(jì)算和分析海洋中電偶源激勵(lì)的低阻體響應(yīng)。結(jié)果說明偽譜法的優(yōu)點(diǎn)是計(jì)算的效率高、精度高,可以呈現(xiàn)出豐富的時(shí)間域的電磁場(chǎng)信息,可以連續(xù)地計(jì)算電磁場(chǎng)的擴(kuò)散過程及與低阻體響應(yīng)的全過程。偽譜法潛在的應(yīng)用領(lǐng)域是海洋瞬變電磁法和礦井瞬變電磁法。如果適當(dāng)?shù)靥幚淼乇砜諝膺吔?就能應(yīng)用于計(jì)算地面瞬變電磁場(chǎng)。本文從麥克斯韋方程組出發(fā),詳細(xì)推導(dǎo)了瞬變電磁法時(shí)域交錯(cuò)采樣有限差分法(FDTD)時(shí)間分步法迭代公式。應(yīng)用交錯(cuò)采樣有限差分法計(jì)算半空間回線源的正演響應(yīng),并與頻率域的計(jì)算結(jié)果進(jìn)行對(duì)比,驗(yàn)證算法的正確性。然后分別計(jì)算低阻體模型、高阻體模型和組合模型的響應(yīng),分析說明TEM的響應(yīng)特點(diǎn)及時(shí)間域電磁法的優(yōu)點(diǎn)。由于TEM方法要處理的觀測(cè)數(shù)據(jù)量巨大,一般的方法進(jìn)行反演的效率很低。本文借鑒地震偏移成像的思想,使用非線性共軛梯度法進(jìn)行反演。利用地表差異場(chǎng)計(jì)算反向傳播場(chǎng),直接在時(shí)間域用入射電場(chǎng)和反傳電場(chǎng)做卷積來計(jì)算數(shù)據(jù)擬合差的梯度,避開計(jì)算雅可比矩陣,應(yīng)用非線性共軛梯度法(NLCG)來搜索目標(biāo)函數(shù)的極小值,找到擬合觀測(cè)數(shù)據(jù)的地電模型。最后本文展示地表差異場(chǎng)對(duì)于地下異常體的反映特點(diǎn),用電場(chǎng)差異場(chǎng)做場(chǎng)源計(jì)算反傳的電磁場(chǎng),使用NLCG反演擬合幾組合成的回線源觀測(cè)數(shù)據(jù)。結(jié)果說明TEM對(duì)低阻體的識(shí)別優(yōu)于高阻體,多源的數(shù)據(jù),會(huì)增加約束,提高反演的效果,反演得到的目標(biāo)體的位置更接近真實(shí)的目標(biāo)體的位置。
[Abstract]:Since 1980s, the transient electromagnetic method (temm) has developed rapidly and has been widely used in many fields, such as oil and gas exploration, engineering exploration, mineral exploration and so on. There is still a long way to go from practical use. Therefore, this paper focuses on the 3-D forward and inverse modeling of transient electromagnetic method. In this paper, pseudospectral method is used to calculate and analyze the response characteristics of high and low resistive bodies in the whole space medium. The results show that the pseudospectral method has the advantages of high efficiency and high accuracy, and can present abundant electromagnetic field information in time domain. The diffusion process of electromagnetic field and the whole process of response to low resistivity body can be calculated continuously. The potential application fields of pseudospectral method are ocean transient electromagnetic method and mine transient electromagnetic method. It can be used to calculate the transient electromagnetic field on the ground. In this paper, we proceed from Maxwell's equations. The iterative formula of time step method of time staggered sampling finite difference method (FDTD) for transient electromagnetic method is derived in detail. The forward response of half-space loop source is calculated by using staggered sampling finite difference method and compared with the calculated results in frequency domain. The validity of the algorithm is verified. Then the responses of the low resistivity model, the high resistivity model and the combined model are calculated respectively. The characteristics of the response of TEM and the advantages of the time domain electromagnetic method are analyzed. Because of the large amount of observation data to be processed by the TEM method, The inversion efficiency of the general method is very low. In this paper, the nonlinear conjugate gradient method is used for inversion using the idea of seismic migration imaging. The reverse propagation field is calculated by using the surface difference field. The gradient of the data fitting error is calculated by convolution of incident electric field and inverse electric field in time domain directly. The nonlinear conjugate gradient method (NLCGG) is used to search the minimum value of the objective function, and the Jacobian matrix is avoided. A geoelectric model for fitting the observed data is found. Finally, the characteristics of the surface differential field reflecting the underground anomalous body are shown. The field source of the electric field difference field is used to calculate the reverse-propagating electromagnetic field. The NLCG inversion is used to fit the observed data of several combined loop sources. The results show that the identification of low resistivity bodies by TEM is superior to that of high resistivity bodies. The data of multiple sources will increase constraints and improve the effect of inversion. The position of the object obtained by inversion is closer to that of the real object.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P631.325

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 殷長(zhǎng)春;任秀艷;劉云鶴;蔡晶;;航空瞬變電磁法對(duì)地下典型目標(biāo)體的探測(cè)能力研究[J];地球物理學(xué)報(bào);2015年09期

2 王猛;劉國(guó)輝;王大勇;劉媛媛;;瞬變電磁測(cè)深資料的ABC算法反演研究[J];地球物理學(xué)進(jìn)展;2015年01期

3 李貅;張瑩瑩;盧緒山;姚偉華;;電性源瞬變電磁地空逆合成孔徑成像[J];地球物理學(xué)報(bào);2015年01期

4 程久龍;李明星;肖艷麗;孫曉云;陳丁;;全空間條件下礦井瞬變電磁法粒子群優(yōu)化反演研究[J];地球物理學(xué)報(bào);2014年10期

5 殷長(zhǎng)春;黃威;賁放;;時(shí)間域航空電磁系統(tǒng)瞬變?nèi)珪r(shí)響應(yīng)正演模擬[J];地球物理學(xué)報(bào);2013年09期

6 李建慧;朱自強(qiáng);魯光銀;曾思紅;;回線源瞬變電磁法的三維正演研究[J];地球物理學(xué)進(jìn)展;2013年02期

7 孫懷鳳;李貅;李術(shù)才;戚志鵬;王yN鵬;蘇茂鑫;薛翊國(guó);劉斌;;考慮關(guān)斷時(shí)間的回線源激發(fā)TEM三維時(shí)域有限差分正演[J];地球物理學(xué)報(bào);2013年03期

8 李建慧;朱自強(qiáng);曾思紅;劉樹才;;瞬變電磁法正演計(jì)算進(jìn)展[J];地球物理學(xué)進(jìn)展;2012年04期

9 閆述;薛國(guó)強(qiáng);陳明生;;大回線源瞬變電磁響應(yīng)理論研究回顧及展望[J];地球物理學(xué)進(jìn)展;2011年03期

10 薛國(guó)強(qiáng);李貅;戚志鵬;范濤;周楠楠;;瞬變電磁擬地震子波寬度壓縮研究[J];地球物理學(xué)報(bào);2011年05期

相關(guān)博士學(xué)位論文 前1條

1 鄧曉紅;定回線源瞬變電磁三維異常特征反演[D];中國(guó)地質(zhì)大學(xué)（北京）;2006年

，

本文編號(hào)：1577699