本文選題：各向異性　切入點：CSAMT　出處：《吉林大學》2017年碩士論文　論文類型：學位論文

【摘要】：可控源音頻地電磁測法(CSAMT)是利用人工源發(fā)出各種頻段的電磁波信號,通過在遠區(qū)接收信號,得到觀測區(qū)域的視電阻率的頻率域測深法。該方法具有較高的分辨率,信噪比高,而且觀測時間短,因此越來越多地被應用在野外勘探中,特別是近年來在地熱勘探方面的應用越來越廣泛。隨著可控源音頻大地電磁法的快速發(fā)展,三維CSAMT正反演理論正成為新的探討的熱點。目前關于可控源音頻大地電磁法三維正演的研究大多是基于各向同性介質(zhì)的,但是由于地下沉積和巖石成分的影響,實際地下介質(zhì)特別復雜,表現(xiàn)出電各向異性,基于各項同性的理想情況很難真實地反映地下構(gòu)造,所以各向異性可控源音頻大地電磁法的研究更有實際意義。此外,在實際勘探中,采用人工源作為場源有利也有弊,與MT相比造成了一些額外的效應,包括各種場源效應和靜態(tài)效應等,這些效應的存在使得卡尼亞視電阻率受到影響,不利于地下構(gòu)造的分析。研究分析各向異性和場源效應對CSAMT實際應用的影響,對可控源三維正反演有著重要意義。本文主要研究了各向異性介質(zhì)中可控源三維數(shù)值模擬的有限差分算法,并應用模擬了可控源電磁法中常見的場源效應和靜態(tài)效應問題。介紹了CSAMT法出現(xiàn)場源效應和靜態(tài)效應的特殊情況,然后介紹了各向異性介質(zhì)中電導率的處理問題,隨后根據(jù)前人在可控源電磁法三維正演和各向異性頻率域電磁正演的研究,以麥克斯韋方程組為起點,獨立地逐步推導了CSAMT包括人工源的控制方程,加入邊界條件,基于交錯采樣有限差分法進行網(wǎng)格剖分,結(jié)合各向異性介質(zhì)的不同方向電阻率不同的特性,構(gòu)建了各向異性介質(zhì)中CSAMT的正演方程組。首先使用Krylov方法預處理得到的大型稀疏矩陣,而后使用QMR算法進行求解,求解過程中加入散度校正方法,加快了方程求解的速度,同時使求解精度得到了保證。利用FORTRAN語言完成了各向異性介質(zhì)中可控源電磁法三維正演模擬程序,隨后利用層狀模型對程序進行了驗證�；谠撊S正演程序分別模擬了各向異性介質(zhì)中的場源效應、靜態(tài)效應,通過設置不同各向異性強度,以及改變異常體的高阻和低阻性質(zhì),得到各種情況下的視電阻率相位曲線,以及XY平面圖和擬斷面圖,并將得到的數(shù)據(jù)與均勻大地各向同性下的數(shù)據(jù)進行對比,分析了各向異性與場源效應和靜態(tài)效應之間的相互關系。
[Abstract]:The controllable source audio ground electromagnetic method (CSAMT) is a frequency-domain sounding method for obtaining the apparent resistivity of the observed region by using artificial sources to send out electromagnetic wave signals in various frequency bands. The method has high resolution and high signal-to-noise ratio (SNR). And the observation time is short, so it is more and more widely used in field exploration, especially in geothermal exploration in recent years. With the rapid development of controllable source audio magnetotelluric method, The theory of 3D CSAMT forward and inverse modeling is becoming a new research hotspot. At present, most of the researches on the 3D forward modeling of controlled source audio magnetotelluric method are based on isotropic media, but due to the influence of underground deposition and rock composition, The actual underground media is very complicated and shows electrical anisotropy. It is difficult to reflect the underground structure in the ideal condition of each homogeneity, so the study of the anisotropic controllable source audio magnetotelluric method is more practical. In addition, the study of the anisotropic controllable source audio magnetotelluric method is more practical. In actual exploration, using artificial source as field source has both advantages and disadvantages. Compared with MT, some additional effects are caused, including various field source effects and static effects, which make Kania apparent resistivity affected. It is not conducive to the analysis of underground structures. The effects of anisotropy and field source effects on the practical application of CSAMT are studied. In this paper, the finite difference algorithm for 3D numerical simulation of controllable sources in anisotropic media is studied. The problems of field source effect and static effect in controlled source electromagnetic method are simulated. The special case of field source effect and static effect by CSAMT method is introduced, and the treatment of conductivity in anisotropic medium is introduced. Then, based on the previous studies on the three-dimensional forward modeling of controllable source electromagnetic method and anisotropic frequency domain electromagnetic forward modeling, and taking Maxwell's equations as the starting point, the governing equations of CSAMT, including artificial sources, are derived step by step independently, and boundary conditions are added. Based on the staggered sampling finite difference method, the meshing method is used to combine the different resistivity characteristics of anisotropic media in different directions. In this paper, the forward equations of CSAMT in anisotropic medium are constructed. The large sparse matrix obtained by Krylov method is preprocessed first, and then solved by QMR algorithm. The divergence correction method is added in the process of solving the equation, which accelerates the speed of solving the equation. At the same time, the accuracy of the solution is guaranteed. The 3-D forward modeling program of controllable source electromagnetic method in anisotropic medium is completed by using FORTRAN language. Then the program is verified by using layered model. Based on the 3D forward program, the field source effect and static effect in anisotropic medium are simulated, and different anisotropic strength is set up. The phase curves of apparent resistivity, XY plane diagram and pseudo-sectional diagram are obtained by changing the properties of high and low resistivity of anomalous bodies, and the obtained data are compared with those of isotropic homogeneous earth. The relationship between anisotropy, field source effect and static effect is analyzed.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：P631.325

【相似文獻】

相關期刊論文 前10條

1 陳小安,章文勛;層狀各向異性介質(zhì)的電磁逆散射[J];應用科學學報;1989年01期

2 B.Mandal ,梁慧云;一般各向異性介質(zhì)中全波形的計算——由各向異性介質(zhì)中爆炸源得出的結(jié)果[J];地球物理學進展;1991年02期

3 Klaus Helbig;任意各向異性介質(zhì)中的軸向[J];石油物探譯叢;1994年01期

4 王澤利,何樵登;用邦德矩陣法推導各向異性介質(zhì)的彈性常數(shù)[J];長春科技大學學報;2000年04期

5 軒義華;何樵登;孟慶生;揣媛媛;湛邵斌;;雙相各向異性介質(zhì)中的擬慢縱波研究[J];石油天然氣學報(江漢石油學院學報);2006年04期

6 房立華;吳建平;;傾斜界面和各向異性介質(zhì)對接收函數(shù)的影響[J];地球物理學進展;2009年01期

7 趙詩華;周志君;朱琴;宋彥琦;;均勻外場中的各向異性介質(zhì)球[J];大學物理;2011年12期

8 李應樂;李瑾;王明軍;董群峰;;各向異性介質(zhì)圓柱的散射特性研究[J];裝備環(huán)境工程;2011年06期

9 李應樂;李瑾;王明軍;董群峰;;均勻各向異性介質(zhì)球散射的解析研究[J];光學學報;2012年04期

10 朱n絳，

本文編號：1581935