本文選題：瞬變電磁法同一回線 + “8”字形回線　； 參考：《東華理工大學》2015年碩士論文

【摘要】：本文的主要研究內(nèi)容為同一回線與“8”字形回線一維正反演。首先介紹了瞬變電磁法的國內(nèi)外的發(fā)展以及研究現(xiàn)狀,主要包括瞬變電磁法的演變、發(fā)展歷程、正反演發(fā)展概況、瞬變電磁法儀器以及系統(tǒng)的發(fā)展現(xiàn)狀及趨勢。其次,介紹了瞬變電磁法的理論基礎及工作原理。然后應用漢克爾變換和G-S變換求解出同一回線裝置的一維正演問題,并根據(jù)“8”字形回線與同一回線線圈上的幾何關系,采用坐標平移法求解出“8”字形回線的一維正演問題,分別作不同地電模型的一維正演曲線圖,并對比之。結(jié)果表明:同一回線與“8”字形回線正演曲線衰減形態(tài)類似,對不同視電阻率的地層都有所反應,不同之處在于“8”字形回線的正演曲線衰減比同一回線快。關于一維反演的研究,首先是視電阻率的定義研究。研究表明:早、晚期的視電阻率只適合極限條件下的視電阻率定義,多數(shù)的實際情況并不能滿足。只有全區(qū)的視電阻率才能滿足多數(shù)情況下的定義,因此文章在反演時采用全區(qū)視電阻率定義。其次對比了平移算法和二分搜索算法對全區(qū)視電阻率計算結(jié)果,結(jié)果表明二分搜索算法在計算晚期視電阻率時更穩(wěn)定。之后闡述了反演的方法,主要說明了煙圈反演與視電導率反演理論,作者選用了常用的煙圈反演方法進行反演。最后在二分法的基礎上,對不同地電模型進行反演成像,繪制出同一回線與“8”字形回線的反演結(jié)果曲線對比圖,并對比二者的反演效果,結(jié)果表明:由于煙圈反演的本身性質(zhì)決定,這兩種裝置的反演結(jié)果在地層分界面處的視電阻率計算值均會發(fā)生畸變;同一回線與“8”字形回線在和模型的擬合程度上都比較理想。不同之處在于“8”字形回線計算出的視電阻率比同一回線略大。為了驗證反演結(jié)果并研究同一回線與“8”字形回線裝置在實際應用上的差異,作者在同一地區(qū)進行了這兩種裝置的實際測量工作,對比二者所得數(shù)據(jù)的質(zhì)量以及各自數(shù)據(jù)解釋成果。結(jié)果表明:“8”字形回線在抗干擾能力方面優(yōu)于同一回線,所計算的視電阻率也比同一回線略大,這一點驗證了理論上的反演結(jié)果。
[Abstract]:The main content of this paper is one-dimensional forward and inverse analysis of the same loop and 8-shaped loop. Firstly, the development and research status of transient electromagnetic method at home and abroad are introduced, including the evolution of transient electromagnetic method, the development course, the general situation of forward and inverse development, the present situation and trend of the instrument and system of transient electromagnetic method. Secondly, the theory and working principle of transient electromagnetic method are introduced. Then using Hankel transform and G-S transform to solve the one-dimensional forward problem of the same loop device, and according to the geometric relation between the "8" shape loop and the same loop coil, The one-dimensional forward modeling problem of "8" zigzag loop is solved by coordinate translation method, and the one-dimensional forward curves of different geoelectric models are made and compared. The results show that the attenuation form of the forward curve of the same loop is similar to that of the "8" curve, and the attenuation of the forward curve of the "8" curve is faster than that of the same loop. The definition of apparent resistivity is the first step in the study of one-dimensional inversion. The results show that the early and late apparent resistivity is only suitable for the definition of apparent resistivity under the limit condition, and most of the actual conditions are not satisfied. Only the apparent resistivity of the whole region can satisfy the definition in most cases, so the definition of apparent resistivity in the whole region is used in inversion. Secondly, the results of translational algorithm and dichotomous search algorithm are compared. The results show that the binary search algorithm is more stable in the calculation of late apparent resistivity. After that, the inversion method is expounded, which mainly explains the theory of smoke ring inversion and apparent conductivity inversion, and the author chooses the commonly used smoke ring inversion method to carry on the inversion. Finally, on the basis of dichotomy, the inversion imaging of different geoelectric models is carried out, and the inversion result curves of the same loop and "8" are drawn, and the inversion results of the two are compared. The results show that the inversion results of these two devices will be distorted at the interface of the formation due to the nature of the smoke ring inversion. Both the same loop and the "8" loop fit well with the model. The difference is that the apparent resistivity calculated by the "8" loop is slightly larger than that of the same loop. In order to verify the inversion result and study the difference between the same loop line and the "8" type loop device in practical application, the author has carried out the actual measurement work of the two devices in the same area. Compare the quality of the two data and the results of their data interpretation. The results show that the anti-jamming ability of "8" loop is better than that of the same loop, and the apparent resistivity calculated is slightly larger than that of the same loop, which verifies the theoretical inversion results.
【學位授予單位】：東華理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P631.325

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本文編號：2100226