可控源音频大地电磁法在松江河某区地热勘查中的应用

发布时间：2018-02-24 03:22

本文关键词： CSAMT 地热勘探全区视电阻率近场效应近场校正　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：地热资源是新型的绿色能源，其勘探开采越来越受到国家和社会的重视。长白山地区地热资源储量丰富，长白山地区的天池火山群和龙岗火山群是我国著名的现代火山活动区，深部岩浆房为该区地热田提供了热源能量，温泉出露点1000多处，具有巨大的开发潜力。可控源音频大地电磁法是通过观测人工场源在大地中激发的电磁场响应的一种电磁测深方法。近年来，CSAMT在深部地热勘探中得到了广泛应用。论文研究了可控源音频大地电磁法的国内外研究现状和可控源音频大地电磁法的基础理论；然后给出了一种把卡尼亚视电阻率换算为全区电阻率的便利方法，采用电场正演迭代拟合卡尼亚视电阻率来进行近场改正。通过建立二、三层电性断面模型，对比分析说明在远区该方法求得的全区视电阻率等于卡尼亚电阻率，，在近区和过渡区则明显改善了卡尼亚视电阻率的畸变。实测CSAMT资料中，对比了基于全区视电阻率的一维反演图、基于卡尼亚视电阻率的一维反演图、用OCCAM法进行的视电阻率一维反演图，以及由卡尼亚视电阻率直接进行带源反演所得一维反演图，说明了该方法的可行性。论文以可控源音频大地电磁法在松江河某区地热勘查中的应用为例，搜集了研究区的地质及地球物理资料。以研究区地质资料为基础、重磁及水文资料为依据，并结合以往周边工作资料，分析探讨研究区电性反演剖面的电性异常特点，并据此初步划分地层、确定断裂构造倾向并确定有利井位。通过CSAMT法在该研究区地热勘查中的研究应用，取得了如下成果和认识： 1、该方法求得的全区视电阻率在远区等价于卡尼亚视电阻率；在近区和过渡区，改正卡尼亚视电阻率畸变效果非常明显。 2、运用全区视电阻率反演能够直观地反映介质电阻率的垂向变化特征，增大了CSAMT探测的深度。 3、该正演方法简便，运算速度较快。在实际工作中，该方法具有较大的应用价值。 4、在研究区的工作，主要取得以下成果： a.研究区从地表到地下2000米，可分为四个构造层。 b.确定了研究区主要有两组断裂，分别为北东东向和近南北向。 c.根据断裂和含水地层的配置关系，确定了两个有利井位。
[Abstract]:Geothermal resources are a new type of green energy, and their exploration and exploitation are paid more and more attention by the state and society. The Changbai Mountain area is rich in geothermal resources, and the Tianchi volcanic Group and Longgang Volcano Group in Changbai Mountain area are famous modern volcanic active areas in China. The deep magma house provides the heat source energy for the geothermal field in this area, and the hot spring has more than 1000 dew points, which has great development potential. The controllable source audio magnetotelluric method is a kind of electromagnetic sounding method for observing the electromagnetic field response excited by artificial field source in the earth. In recent years, CSAMT has been widely used in deep geothermal exploration. The controllable source is studied in this paper. The present situation of audio magnetotelluric method at home and abroad and the basic theory of controllable source audio magnetotelluric method; Then a convenient method of converting Kania apparent resistivity into the whole area resistivity is given, and the electric field forward iteration fitting Kania apparent resistivity is used to carry out near field correction. The contrast analysis shows that the apparent resistivity obtained by this method in the far region is equal to that of Kania resistivity, while the distortion of Kania apparent resistivity is obviously improved in the near and transitional regions. The one-dimensional inversion map based on the whole area apparent resistivity, the one dimensional inversion map based on the Kania apparent resistivity, the one dimensional inversion map of the apparent resistivity using OCCAM method, and the one dimensional inversion map obtained by the direct band source inversion from Kania apparent resistivity are compared. The feasibility of the method is illustrated. Taking the application of controllable source audio frequency magnetotelluric method in the geothermal exploration of a certain area of Songjiang River as an example, the geological and geophysical data of the study area are collected, which are based on the geological data of the study area, gravity, magnetic and hydrological data. Based on the previous peripheral working data, the characteristics of electrical anomaly in the electric inversion section of the study area are analyzed and discussed, and the strata are preliminarily divided according to the characteristics. The research and application of CSAMT method in geothermal exploration of the study area have obtained the following results and understanding:. 1. The whole apparent resistivity obtained by this method is equivalent to Kania apparent resistivity in the far region, and the correction effect of Kania apparent resistivity distortion is very obvious in the near region and transition region. 2. Using the whole area apparent resistivity inversion can directly reflect the vertical variation characteristics of the resistivity of the medium and increase the depth of CSAMT detection. 3. The forward modeling method is simple and fast, and has great application value in practice. 4. The main achievements of the work in the study area are as follows:. A. The study area can be divided into four tectonic layers from surface to underground for 2000 meters. B. it is determined that there are two groups of faults in the study area, which are east-west and north-south respectively. According to the relationship between fault and water bearing formation, two favorable wells are determined.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.325

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