A Study of the Method for the Recognition of Anomalies in Geochemical Hydrocarbon Exploration

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A Wavelet-Analysis-Based New Approach for Interference Elimination in Geochemical Hydrocarbon Exploration

Guidance for petroleum prospecting is provided by authentic geochemical anomalies, obtained after interference has been eliminated in the original data from a geochemical survey for hydrocarbons. However, this elimination is a complicated process. Few working models or effective methods for interference elimination have been proposed, hampering a wider acceptance of geochemical prospecting as a viable tool for hydrocarbon exploration. This study focuses on the models for different types of interference and developing techniques for interference elimination. We first restudied the geometric nature of hydrocarbon anomalies and interference on the basis of Zhang, L., and Lia, Z. (J. China Univ. Geosci., v. 9, no. 1, p. 72–80, 1998). From this, we determined that at least two types of interference are present in the data of a surface geochemical survey for hydrocarbons. One is the superimposition type originating mainly from microorganisms and contamination, and the other is the multiplication type resulting from variations in soil mineral components. We then established digital conceptual models for both types of interference based on the geometry of anomalies and interference. Finally, we used wavelet analysis to eliminate both types of interference in the models for testing. As Morlet wavelet and symmetric border treatment fit the geometric characteristics of the anomalies and interference, they were used in this study. We found that pre-wavelet analysis treatment is different for different types of interference. For the multiplication type, log-transformation and normalization are needed before wavelet analysis whereas only normalization is needed for the superimposition type. In practice, one needs to identify the type of interference. Therefore, the criteria for determining the interference type were first established geochemically in this study. The newly developed techniques were then applied to the data of acid-extractable hydrocarbons of soils in the Eastern Anan Sag, Inner Mongolia where traditional techniques had failed to eliminate the interference in these data. Using our new techniques, we determined the interference was the multiplication type. This new approach enabled us to satisfactorily eliminate the interference in the original data. It should be noted that our study indicates that the multiplication type of interference is much more common and severe than previously thought.     

2011~2020年勘查地球化学数据处理研究进展

我国建立了包含海量数据的高质量的勘查地球化学数据库,为矿产勘查、环境评价和地质调查等提供了重要的数据支撑。如何高效处理勘查地球化学数据,并从中发掘和识别深层次信息一直是勘查地球化学学科研究的热点和前沿领域。本文在系统调研国内外学者过去十年发表的论著基础上,对勘查地球化学数据处理方法进行分析与对比,从勘查地球化学数据库建设、地球化学异常识别及其不确定性评价等方面概述了我国近十年来在该领域取得的主要研究进展,包括:(1)分形与多重分形模型由于考虑了地球化学空间模式的复杂性和尺度不变性,在全球范围内得到极大的发展和推广,我国学者引领了基于分形与多重分形的勘查地球化学数据处理;(2)机器学习和大数据思维开始在该领域启蒙,并迅速得到关注,正在成为研究热点和前沿领域,我国学者率先开展基于机器学习算法的勘查地球化学大数据挖掘研究;(3)我国学者需要进一步加强勘查地球化学数据缺失值处理以及成分数据闭合效应研究。今后该领域应进一步加强对弱缓地球化学异常识别、异常不确定性评价以及异常识别与其形成机理相结合等方面的研究。     

物化探技术在非金属矿勘查中的应用

阐述了非金属矿产对国民经济的重要性,针对非金属矿产勘查中物化探技术的现状,就物化探技术在非金属矿勘查中应用的意义、发展方向及重点等提出见解。     

识别分散矿化的地球化学勘查方法探讨——以内蒙古垦山试验区为例

分散矿化的识别对提高地质找矿工作效率、适量控制资金投入具有重要意义．但是有关这方面的试验研究工作很不系统。文章以内蒙古垦山地区经钻孔验证未见矿的多元素组合异常为例,通过原生异常特征、矿石矿物化学计量关系、贫化元素指示作用等方面的综合分析,对识别分散矿化的地球化学勘查方法进行了探讨。结果表明,原生异常分带及元素组合特征是...     

铅同位素方法应用于化探找矿评价

铅同位素方法应用于化探找矿评价常向阳朱炳泉（中国科学院广州地球化学研究所，广州５１０６４０）关键词铅同位素打靶系统剖面化探收稿日期：１９９６－１２－１７第一作者简介：常向阳男１９６７年生助理研究员同位素地球化学＊国家科委攀登计划Ｂ项资助近年来，铅同位...     

勘查地球化学异常多尺度分析方法——以赣东北德兴矿集区为例

以赣东北德兴矿集区铜元素地球化学数据为例,提出了一种勘查地球化学异常多尺度分析的方法,内容包括:(1)采用具有平移不变性的平稳小波变换进行勘查地球化学异常的多尺度分解;(2)随着小波分解阶数的增大,在多尺度逼近累积频率—含量曲线图上,如果数据分布较均匀,没有出现明显的拐点,则该尺度逼近可以作为最大尺度的背景,该分解阶数为最大分解阶数;(3)各尺度的逼近不能直接代表该尺度的背景,各尺度的背景都是起伏的带而不是曲面,在多尺度细节累积频率—含量曲线图上,以拐点作为各尺度的异常下限;(4)大尺度的细节主要反映区域性的控岩控矿信息,而异常的形态和规模对研究控矿地质因素很重要,直接将各细节的正值作为异常;(5)小尺度的细节的正值分布过于复杂,分布规律不明显,因此一定要进行异常的提取,异常主要反映由矿和蚀变引起的局部变化,具有重要的找矿价值;(6)在各个尺度均表现为异常的区域具有找矿远景,特别是小尺度的局部异常,其不同尺度重叠区域是重要的找矿远景区。勘查地球化学异常的多尺度分析可获得多尺度的曲面背景和对应的异常,并可得到异常的精细结构,突出异常的局部变化特征,从而更有效地识别与矿有关的异常。     

综合物化探在朱拉扎嘎金矿扩大过程中的作用

综合物探普查 ,朱拉扎嘎矿区已圈定出 1 8km2 磁异常和激电异常 ,推断 1 8km2 磁异常和激电异常均为原生硫化物金矿层引起 ,已施工的 1 8个钻孔均见矿 ,估算黄金储量 >50 0 t     

Laboratory Simulation of the Formation Process of Surface Geochemical Anomalies Applied to Hydrocarbon Exploration

The formation mechanisms and processes of geochemical anomalies used as proxies in surface geochemistry exploration (SGE) have not been well understood. Previous studies cannot realize 3D measurement of microseeping hydrocarbons from reservoirs to the surface, which made it difficult to understand the features and pathways of deep hydrocarbon microseepages. Understanding the processes of hydrocarbon microseepages will contribute to the acceptance and effectiveness of surface geochemistry. Based on a simplified geological model of hydrocarbon microseepages, including hydrocarbon reservoir, direct caprock, overlying strata and Quaternary sediments, this work established a 3D experimental system to simulate the mechanisms and processes of deep hydrocarbon microseepes extending to the surface. The dispersive halos of microseeping hydrocarbons in the subsurface were adequately described by using this 3D experimental system. Results indicate that different migration patterns of hydrocarbons above the point gas source within the simulated caprock and overlying strata can be reflected by the ratio of i-butane to n-butane (i-C4/n-C4), which follow diffusion and infiltration (buoyancy) mechanisms. This is not the case for vertical measurement lines far from the point gas source. A vertical gas flow in the form of a plume was found during hydrocarbon microseepage. For sampling methods, the high-density grid sampling is favorable for delineating prospecting targets. Hydrocarbon infiltration or buoyancy flow occurs in the zones of infiltration clusters, coupling with a diffusion mechanism at the top of the water table and forming surface geochemical anomalies. These results are significant in understanding hydrocarbon microseepage and interpreting SGE data.     

Research and Application of New Methods to Oil-Gas Geochemical Exploration

Based on the results of researches and applications for many years, it has been discovered that new methods and techniques for geochemical exploration of oil and gas such as AC, altered carbonate, Hg in absorption phase, Ks, Fe2+ ,δ13C, fluorescence in two and three dimensions, and N2 and O2 in heat release can give full play in the following five fields: (1) optimization of the favourable target or hollow zones and structural zones in a region; (2) evaluation of oil traps and delineation of prospective oil and gas areas; (3) prediction of deep-seated oil-bearing horizons; (4) evaluation of the genesis of oil and gas geochemical anomalies and determination of the types of oil and gas accumulations; (5) forecast of the burial depths of oil and gas pools.     

大比例尺化探数据库建库工作流程

通过对大比例尺化探数据库建库的试点工作，总结出一套数据采集的工作方法，对今后此类工作具有一定借鉴意义。     

手持式GPS在化探工作中的应用

主要论述在化探预查和普查阶段使用手持式GPS,实现了单点绝对定位,很大程度上提高了野外定点的精度,降低了工作强度,简化了工作程序,保证了工作质量。GPS在化探工作中的使用必须按照必要程序进行,为保证精度,必须进行GPS试验,主要包括控制点的选择,仪器参数校正,精度试验,多台GPS一致性检查,并明确给出该地区GPS能否使用报告。通过野外实例充分说明了利用手持式GPS的定位方法在地球化学勘查中应用的效果,利用GPS航迹跟踪功能验收当天野外工作,制作航迹监控图、野外实际材料图,利用GPS和MAPGIS制作地质简图及化探测网的布设。重点讨论了GPS有关参数的设定、校正及准确度等细节,从而保证地球化学勘查测点定点的精度和质量。     

小波分析在分探异常处理中的试验研究——以四川石棉田湾矿区为例

本文介绍了小波分析的基本原理及特点,并从小波变换的思想出发,将之应用于化探异常处理之中,以求在各种级别的背景异常中提取出矿化异常,并以四川省石棉县田湾区化探异常处理为例,实验结果表明小波分析有化探领域具有广阔的应用前景。     

基于逻辑回归模型的化探异常信息识别研究——以克拉玛依地区为例

化探数据对矿产资源勘查工作有着重要作用,其中比较关键的工作就是从化探数据中识别矿床相关的化探异常信息.在化探异常信息识别工作中也发展出了较多的技术,但是它们大多针对单变量进行分析.为了对多变量化探数据进行分析并识别金矿相关的地球化学异常信息,笔者将逻辑回归模型用于研究区化探数据分析,通过研究区内对金矿预测比较有价值的16种元素的逻辑回归建模及模型应用,发现逻辑回归是一种有效的化探多变量数据分析和建模技术,研究结果显示,笔者建立的逻辑回归模型不仅可以有效识别已知金矿区的地球化学异常信息,而且对那些还未发现矿床的区域具有预测作用,能够为矿产资源勘查工作重点区域的选择提供指导.     

车载台式能量色散X射线荧光光谱仪在地球化学勘查现场分析中的应用

充分发挥小型实验室设备的功能以提高现场快速分析的能力。在内蒙和新疆两地覆盖区的钻探现场,采用车载化台式偏振能量色散X射线荧光光谱仪,对由轻便钻采集的覆盖层和基岩样品进行了贱金属分析。共采集、制备和分析了约400件钻探样品,采用能量色散X射线荧光光谱法、波长色散X射线荧光光谱法和电感耦合等离子体质谱法对这些样品进行比对分析。现场分析数据与实验室分析数据(各方法的平均值)的比对结果表明,K、Ca、Ti、V、Cr、Mn、Fe、Ni、Cu、Zn、Ga、As、Rb、Sr、Y、Zr、Nb、Ba、Pb、Th等20余种元素的分析数据的一致性良好;含量超过10μg/g时,除了V和Ba外,其他元素的平均相对偏差均小于25%。在现场作为质控样品分析4个地质标准物质GBW07301～GBW07304,测定结果表明,除了低含量的Cu和Ga外,上述其他18种元素均符合地质行业标准地质矿产实验室测试质量管理规范(1∶20万)规定的误差要求。应用研究表明,设计的仪器车载化方案可行,现场分析方法快速、准确,适用于野外钻探、化探等急需现场数据支持的工作。     

沟系土壤地球化学测量在贵州普晴锑金矿勘查区应用与找矿效果

通过沟系土壤地球化学测量方法在普晴锑金矿勘查区中的实施,确定各元素异常下限值为Au7×10-9、Sb10×10-6、Cu200×10-6、As30×10-6,发现了一批有价值的地球化学异常,对各元素地球化学异常区的找矿潜力进行分析,结合地层、岩性等有利控矿因素综合评判主成矿元素异常、元素组合异常圈定4个找矿靶区,确定了各靶区的主要找矿矿种,对各靶区进行了必要的山地工程查证,取得了较好的找矿效果。实践证明沟系土壤地球化学测量找矿方法在本区是有效的,认识到在当前老矿区外围找矿中成矿元素弱异常、多元素组合弱异常区具有重要找矿意义。在此基础上较系统的总结了沟系土壤地球化学找矿方法步骤。     

A Fractal Interpolatory Approach to Geochemical Exploration Data Processing

Traditional interpolation procedures used for processing geochemical data treat the data as a continuous smooth surface. In this paper, we proposed a fractal spatial interpolatory procedure based on the concept of the fractional delta variance. The method is suitable for processing the geochemical data that are measured at irregularly spaced discrete points, without resort to gridding procedures. The value at each interpolatory point is a function of the fractal disturbance that is related to the fractal dimension determined from the original data set, thus enhancing reconstruction of the natural spatial distribution of element concentration. The proposed procedure has been applied to the copper geochemical data measured from irregularly-spaced floodplain sediment samples in China. We compared geochemical maps created using different interpolatory procedures, including the new fractal method, the Kriging, and the weighted average, against the actual spatial distribution of copper mineral deposits in China, and found that the new fractal method detected more of known Cu-deposits from the test area than the other two methods.     

东营凹陷金东—柳桥地区油气化探数据中的地表干扰与排除

东营凹陷南斜坡金东—柳桥地区地表条件复杂,化探信号干扰强烈,造成假异常大面积出现。在对金东—柳桥地区油气化探数据中干扰类型识别的基础上,用Mallat小波分析法,发现分析尺度为3时的连续序列呈现出地表干扰信息,由此进行了地表干扰排除。经过封盖条件校正与异常识别,获得了该区油气化探异常。干扰排除后的异常与断层、圈闭及已发现的油气藏或油气显示相吻合,表明这些异常主要反映的是地下油气藏信息。     

非负矩阵分解方法在水系沉积物地球化学数据处理中应用

鉴于水系沉积物地球化学数据可以表示为非负矩阵,这使得利用非负矩阵分解(NMF)方法处理该类数据成为可能.介绍了非负矩阵分解方法的基本原理和方法,讨论了基于非负矩阵分解方法处理水系沉积物地球化学数据的可能和效果.以个旧水系沉积物地球化学数据为例,运用NMF方法和主成分分析(PCA)方法对其进行异常分析,并对这两种方法的处理结果进行了比较,发现NMF方法对于处理水系沉积物地球化学数据是一种有效的方法.尽管这两种方法各自有其优越性,但就本实例数据而言,NMF方法优于PCA方法.     

1：20万区域化探样品的分析测试质量监控

报道了1：20万区域化探样品分析的质量监控方式及利用局域网实现1：20万区域化探样品分析自动化的质量监控体系。