天然场激发极化中岩矿石频谱特征的模型与实验研究

发布时间：2018-04-11 23:12

本文选题：IP模型 + 天然岩(矿)石　；参考：《中国地质大学(北京)》2017年博士论文

【摘要】：前人通过实验室和野外测量提出了 12种模型用于描述天然岩(矿)石的激发极化效应(IP效应),这些模型在矿产资源勘查、地质构造调查等方面获得了广泛的应用。本文基于大量的数值模拟计算和对比分析、进行天然岩(矿)石的相位谱试验和反演拟合试验对有代表性的七种模型描述IP的性能进行系统研究。目的是确定表征不同类型天然岩(矿)石IP效应的最有效模型。首先利用Delphi7编写程序用于计算七种模型的振幅、相位、实部、虚部相位谱,系统研究了七种模型的所有激电参数对相位谱的影响规律及频谱表征范围。然后利用SolartronSI-1260频谱仪对来自16个地区不同矿种的50余块天然岩(矿)石样本进行10-3～105Hz范围的扫频测量,获得了各样本的相位谱并总结分析了相位谱的特征规律。为了研究七个模型的性能,通过Matlab平台编写了基于最小二乘和差分进化算法的反演程序,对呈现单峰和双峰频谱特征的样本试验数据分别进行反演拟合试验。分析考察各模型的拟合相位谱与样本实测相位谱的吻合程度,拟合精度用百分均方根误差评价。七个模型的拟合精度可直观对比并由此确定各种天然岩(矿)石对应的最有效模型。研究结果表明:Dias和Multi- Cole-Cole模型最适宜表征呈单峰和双峰特征的金属矿物的相位谱;利用这两种模型系统地对多种矿物的双峰相位谱数据直接反演拟合获得高精度拟合曲线尚属首次。Warburg,Cole-Cole和Generalized Cole-Cole模型适宜表征呈单峰特征的金属矿物的相位谱。Madden and Cantwell模型适宜表征含银闪锌-方铅矿和含金黄铁矿的频谱,但对其他矿物的表征能力较低。Debye模型对所有矿物的拟合精度较低。综上所述,7种模型表征相位曲线的峰值、峰位和峰宽的能力不同,实际野外工作中,在某些条件下如选用不合适的IP模型进行正反演分析将会导致很大的误差。因此,针对不同的矿物类型选择合适的模型尤其重要。该结论能够为频率域激电法应用于矿产勘查选择合适的模型提供理论依据。本文还新提出了一种新的激电参数-峰值相位差φp,结合相对视频散率PPs构成一组有效参数表征矿体的激电异常,为实际应用提供了一种新思路。
[Abstract]:Through laboratory and field measurements, 12 models have been proposed to describe the induced polarization effect of natural rock (ore) and IP effect. These models have been widely used in mineral resources exploration, geological structure survey and so on.In this paper, based on a large number of numerical simulation and comparative analysis, phase spectrum test and inversion fitting test of natural rock (ore) stone are carried out to systematically study the performance of seven representative models to describe IP.The aim is to determine the most effective model to characterize the IP effect of different types of natural rocks (ores).Firstly, the Delphi7 program is used to calculate the amplitude, phase, real part and imaginary part phase spectrum of seven models. The influence of all the IP parameters of the seven models on the phase spectrum and the spectrum representation range are systematically studied.Then more than 50 samples of natural rock (ore) from 16 regions were measured by SolartronSI-1260 spectrometer in 10-3~105Hz range. The phase spectrum of each sample was obtained and the characteristic law of phase spectrum was summarized and analyzed.In order to study the performance of the seven models, an inversion program based on least squares and differential evolution algorithm was compiled on the Matlab platform.The fitting phase spectrum of each model is consistent with the measured phase spectrum of the sample, and the fitting accuracy is evaluated with the percentage root mean square error (RMS) error.The fitting accuracy of the seven models can be compared intuitively and the most effective models corresponding to various natural rocks (minerals) can be determined.The results show that the phase spectra of metallic minerals with single and double peaks are best characterized by the 1: Dias and Multi- Cole-Cole models.It is the first time that the two models are used to directly inverse fitting the bimodal phase spectrum data of many minerals to obtain the high-precision fitting curves. Warburg Cole-Cole and Generalized Cole-Cole models are suitable for characterizing the phase spectrum of metallic minerals with single peak. Madden and Cantwell model.The spectrum of zinc-galena and gold-bearing pyrite is suitable for characterizing the frequency spectrum of silver containing zinc-galena and gold-bearing pyrite.In summary, the seven models can represent the peak value, peak position and peak width of the phase curve. In practical field work, if we choose the inappropriate IP model for forward and inverse analysis under some conditions, it will lead to great error.Therefore, it is particularly important to select suitable models for different mineral types.This conclusion can provide theoretical basis for the application of frequency domain IP method in mineral exploration and selection of suitable models.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P631

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