本文關(guān)鍵詞： 自然電位 非耦合分析理論 孔隙度 彌散度　出處：《南京大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：自然電位作為地球物理探測的重要于段之一,在水文地質(zhì)領(lǐng)域中得到了廣泛的應(yīng)用。由于自然電位能夠直接反應(yīng)水流流動和溶質(zhì)運(yùn)移過程,其在反應(yīng)水流流動和獲取水文地質(zhì)參數(shù)方面有著其它地球物理學(xué)方法所不具備的優(yōu)勢。因此,研究基于自然電位獲取多孔介質(zhì)孔隙度與彌散度的方法具有十分重要的意義。利用自然電位獲取多孔介質(zhì)孔隙度和彌散度的方法目前大體上可分為兩類：一是基于耦合分析理論的方法,二是基于非耦合分析理論的方法�；隈詈戏治隼碚摣@取孔隙度和彌散度的方法計(jì)算復(fù)雜且用時較長,而基于非耦合分析理論獲得孔隙度與彌散度的方法目前也沒能對所測的自然電位曲線進(jìn)行完整的擬合,實(shí)現(xiàn)對相關(guān)參數(shù)的準(zhǔn)確提取。為此,在本研究中,通過室內(nèi)砂柱、砂箱的鹽脈沖實(shí)驗(yàn),同時高密度的監(jiān)測實(shí)驗(yàn)過程中不同觀測位置的自然電位時問變化過程,通過自然電位非耦合分析理論理論和滲流理論,探討了獲取多孔介質(zhì)的有效孔隙度和彌散度的方法,為室內(nèi)獲取多孔介質(zhì)的孔隙度和彌散度提供一種便捷、無損和高密度的方法。通過本研究獲得了以下成果：(1)采用非耦合分析理論建立了針對一維均質(zhì)多孔介質(zhì)的自然電位擬合模型。通過該模型對實(shí)測自然電位的擬合,獲得了實(shí)驗(yàn)用多孔介質(zhì)的孔隙度和彌散度參數(shù)。通過與滲流理論獲得的參數(shù)的比較,說明了所得孔隙度和彌散度參數(shù)是可靠的。由于所得孔隙度為水流實(shí)際通過孔隙的孔隙度,本研究中所獲得的孔隙度為有效孔隙度。(2)通過滲流理論獲取孔隙度的方法不僅適用于均質(zhì)介質(zhì)條件同時也適用于非均質(zhì)介質(zhì)條件。但基于自然電位的非耦合分析理論獲取孔隙度的方法在非均質(zhì)多孔介質(zhì)條件下存在一定的不足,對實(shí)測自然電位的擬合結(jié)果不理想。多孔介質(zhì)的非均質(zhì)性在實(shí)測自然電位的時間變化曲線上通過雙峰甚至多峰的現(xiàn)象體現(xiàn)出來,說明自然電位仍然能夠在一定程度上反映出多孔介質(zhì)的非均質(zhì)性。(3)高密度的自然電位監(jiān)測和由此所獲得的參數(shù),為我們建立多孔介質(zhì)孔隙度和彌散度的空間分布場創(chuàng)造了條件。雖然在本研究中我們僅僅獲得了孔隙度和彌散度在一維空間的分布,但它為我們在二維甚至三維條件下建立孔隙度和彌散度的空間分布場提供了一條重要的途徑。(4)在二維條件下通過自然電位成像監(jiān)測本研究實(shí)現(xiàn)了對二維溶質(zhì)運(yùn)移過程的監(jiān)測,這為我們研究實(shí)際流場、驗(yàn)證滲流場的數(shù)值模擬結(jié)果、認(rèn)識多孔介質(zhì)中的溶質(zhì)運(yùn)移過程等都具有重要意義。
[Abstract]:As an important part of geophysical exploration, natural potential has been widely used in hydrogeology, because natural potential can directly reflect the flow of water and solute transport process. It has advantages not available in other geophysical methods in terms of reacting the flow of water and obtaining hydrogeological parameters. It is of great significance to study the methods of obtaining porosity and dispersion of porous media based on natural potential. At present, the methods of obtaining porosity and dispersion of porous media by natural potential can be divided into two categories:. One is the method based on coupling analysis theory. The second is the method based on the decoupling analysis theory, the method of obtaining porosity and dispersion based on the coupling analysis theory is complicated and takes a long time. However, the method of obtaining porosity and dispersion based on decoupling analysis theory has not been able to complete fitting the measured natural potential curve, and to achieve the accurate extraction of relevant parameters. Therefore, in this study. Through the indoor sand column, sand box salt pulse experiment, at the same time, the high-density monitoring experiment process of different observation positions of natural potential time change process, through the natural potential non-coupling analysis theory and seepage theory. The method of obtaining effective porosity and dispersion of porous media is discussed, which provides a convenient method for obtaining porosity and dispersion of porous media in laboratory. Nondestructive and high-density methods. The following results have been obtained from this study: 1). The natural potential fitting model for one-dimensional homogeneous porous media is established by using the theory of non-coupling analysis, and the measured natural potential is fitted by the model. The parameters of porosity and dispersion of porous media for experimental purposes are obtained and compared with those obtained by seepage theory. It is shown that the obtained porosity and dispersion parameters are reliable, because the obtained porosity is the porosity of the flow through the pore. The porosity obtained in this study is effective porosity. The method of obtaining porosity by seepage theory is not only suitable for homogeneous medium condition but also suitable for heterogeneous medium condition. However, the method of obtaining porosity based on uncoupled analysis theory of natural potential is applied in heterogeneous porous media. There are some shortcomings under the condition. The heterogeneity of porous media is reflected in the time-varying curve of measured natural potential by the phenomenon of double peaks or even multiple peaks. It shows that the natural potential can still reflect the heterogeneity of porous media to some extent) the high density of natural potential monitoring and the parameters obtained therefrom. The conditions are created for us to establish the spatial distribution field of porosity and dispersion in porous media, although in this study we have only obtained the distribution of porosity and dispersion in one-dimensional space. But it provides an important way for us to establish the spatial distribution field of porosity and dispersion under two-dimensional or even three-dimensional conditions. Monitoring of Solute Migration in Two-Dimensional condition by Natural potential Imaging in this study. It is of great significance for us to study the actual flow field, verify the numerical simulation results of the seepage field, and understand the solute migration process in porous media.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.3;P641.7
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本文編號：1473649