Application of 3-D Geoscience Modeling Technology for the Estimation of Solid Mineral Reserves

Abstract: Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology (3-D GMT), this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT: building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.     

The Present Research and Prospect of Chinese Geosciences History

It has been over a hundred years since the birth of research on Chinese geosciences history, which was accompanied by the continuous progress of Chinese geosciences. For hundreds of years, it has grown out of nothing to brilliant performance by several generations of Chinese geologists committing their hearts and minds with the spirit of exert and strive without stop to promote the process of China's industrialization and to produce the significant impact on serving the society. The study of Chinese geosciences history reflects objectively and historically the history of geosciences in China, which has recorded, analyzed and evaluated the dynamic process sitting in the background and clue of the history of Chinese geosciences development. The study of the history of geological science has roughly experienced two stages in China. The first stage is the study of individual researchers. It spanned approximately 70 years from the early 20th century to the end of the 1970s. The research contents were mainly based on the evolution of geological organizations, the development and utilization of individual mineral species, the history of deposit discovery and the research of geological characters. The main representatives are Zhang Hongzhao, Ding Wenjiang, Weng Wenhao and Li Siguang, Ye Liangfu, Huang Jiqing, Yang Zhongjian, Xie Jiarong, Gao Zhenxi, Wang Bingzhang and etc. The most prominent feature of this period is the accumulation of a very valuable document for the study of the history of China's geological history and lays a foundation for the exchange of geological science between China and foreign countries. The second stage is organized group study. It took around 60 years from the 1920s to 1980s. It includes the history of Chinese geology, the history of geological organizations, the history of geological disciplines, the history of geological education, the history of geological philosophy, the history of Chinese and foreign geological science communication, the history of geologists and etc. The most chief feature of this stage is the birth of academic research institute―the establishment of the Commission on the History of Geology of the Geological Society of China.     

http://www.sciencedirect.com/science/article/pii/S1674987111001411

正Three-dimensional geological modeling(3DGM) assists geologists to quantitatively study in three-dimensional(3D) space structures that define temporal and spatial relationships between geological objects.The 3D property model can also be used to infer or deduce causes of geological objects.3DGM technology provides technical support for extraction of diverse geoscience information,3D modeling,and quantitative calculation of mineral resources.Based on metallogenic concepts and an ore deposit model, 3DGM technology is applied to analyze geological characteristics of the Tongshan Cu deposit in order to define a metallogenic model and develop a virtual borehole technology;a BP neural network and a 3D interpolation technique were combined to integrate multiple geoscience information in a 3D environment. The results indicate:(1) on basis of the concept of magmatic-hydrothermal Cu polymetallic mineralization and a porphyry Cu deposit model,a spatial relational database of multiple geoscience information for mineralization in the study area(geology,geophysics,geochemistry,borehole,and cross-section data) was established,and 3D metallogenic geological objects including mineralization stratum,granodiorite, alteration rock,and magnetic anomaly were constructed;(2) on basis of the 3D ore deposit model,23,800 effective surveys from 94 boreholes and 21 sections were applied to establish 3D orebody models with a kriging interpolation method;(3) combined 23,800 surveys involving 21 sections,using VC++ and OpenGL platform,virtual borehole and virtual section with BP network,and an improved inverse distance interpolation(IDW) method were used to predict and delineate mineralization potential targets (Cu-grade of cell not less than 0.1%);(4) comparison of 3D ore bodies,metallogenic geological objects of mineralization,and potential targets of mineralization models in the study area,delineated the 3D spatial and temporal relationship and causal processes among the ore bodies,alteration rock,metallogenic stratum,intrusive rock,and the Tongshan Fault.This study provides important technical support and a scientific basis for assessment of the Tongshan Cu deposit and surrounding exploration and mineral resources.     

Relationship between Geological Structures and Hydrocarbon Enrichment of Different Depressions in the Bohai Bay Basin

The Bohai Bay Basin contains many depressions with varying degrees of hydrocarbon enrichment associated with the geological structures of different depressions. This study discussed the relationship between the geological structures and hydrocarbon enrichment of the depressions in the Bohai Bay Basin. Based on the Paleogene strata distribution and the length to width ratio of different depressions, their geological structures are divided into three types in plan-view: open(length/width 2), narrow(length/width 4) and transitional types(length/width 2–4). In cross section, the geological structures can be divided into dustpan I, dustpan II and double-faulted types. Based on tectonic evolution and sedimentary characteristics, the depressions are classified into early-formed, inherited and late-formed categories. Generally, narrow depressions are mainly located in the northeast and southwest of the Bohai Bay Basin, while open depressions are dominantly distributed in the central area of the basin; late-formed depressions are mainly around the Bohai sea area, and early-formed depressions are mostly located in the periphery of the basin. Geological structures of the depressions control the formation of the source, reservoir and cap rocks as well as hydrocarbon accumulation setting, and further influence the pay zones and oil-bearing sequence. In detail, dustpan II and doublefaulted depressions mainly have A-type sags, which often possess better hydrocarbon generation conditions than dustpan I ones; hydrocarbons in open dustpan II depressions tend to accumulate in the central uplift areas or buried hill, while those in narrow dustpan I depressions always accumulate in gentle slope belts. The oil-bearing sequence for different evolutional depressions corresponds well with the sedimentary strata of the main development stages of depressions. In early-formed depressions, hydrocarbons are mainly enriched in deeply buried reservoirs, while in late-formed depressions hydrocarbons are abundant in the relatively shallow traps. In summary, most inherited and late-formed dustpan II depressions are enriched in hydrocarbons due to their extensive source rocks and good source–reservoir–seal assemblages, whereas dustpan I and early-formed depressions are relatively poor in hydrocarbons.     

Potential and Suitability Evaluation of CO2 Geological Storage in Major Sedimentary Basins of China, and the Demonstration Project in Ordos Basin

From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey (CHEGS) carried out the project “Potential evaluation and demonstration project of CO2 Geological Storage in China”. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2 geological storage based on China’s geological conditions, and evaluated the potential and suitability of the primary basins for CO2 geological storage, in order to draw a series of regional scale maps (at a scale of 1:5000000) and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2 storage. We also built techniques and methods for site selection and the exploration and assessment of CO2 geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2 geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2 storage in deep saline aquifers under China’s geological conditions.     

Potential and Suitability Evaluation of CO2 Geological Storage in Major Sedimentary Basins of China, and the Demonstration Project in Ordos Basin

From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey (CHEGS) carried out the project “Potential evaluation and demonstration project of CO2 Geological Storage in China”. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2 geological storage based on China’s geological conditions, and evaluated the potential and suitability of the primary basins for CO2 geological storage, in order to draw a series of regional scale maps (at a scale of 1:5000000) and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2 storage. We also built techniques and methods for site selection and the exploration and assessment of CO2 geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2 geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2 storage in deep saline aquifers under China’s geological conditions.     

Sedimentary Microfacies and Porosity Modeling of Deep-Water Sandy Debris Flows by Combining Sedimentary Patterns with Seismic Data: An Example from Unit I of Gas Field A, South China Sea

Sandy debris flow deposits are present in Unit I during Miocene of Gas Field A in the Baiyun Depression of the South China Sea. The paucity of well data and the great variability of the sedimentary microfacies make it difficult to identify and predict the distribution patterns of the main gas reservoir, and have seriously hindered further exploration and development of the gas field. Therefore, making full use of the available seismic data is extremely important for predicting the spatial distribution of sedimentary microfacies when constructing three-dimensional reservoir models. A suitable reservoir modeling strategy or workflow controlled by sedimentary microfacies and seismic data has been developed. Five types of seismic attributes were selected to correlate with the sand percentage, and the root mean square (RMS) amplitude performed the best. The relation between the RMS amplitude and the sand percentage was used to construct a reservoir sand distribution map. Three types of main sedimentary microfacies were identified: debris channels, fan lobes, and natural levees. Using constraints from the sedimentary microfacies boundaries, a sedimentary microfacies model was constructed using the sequential indicator and assigned value simulation methods. Finally, reservoir models of physical properties for sandy debris flow deposits controlled by sedimentary microfacies and seismic inversion data were established. Property cutoff values were adopted because the sedimentary microfacies and the reservoir properties from well-logging interpretation are intrinsically different. Selection of appropriate reservoir property cutoffs is a key step in reservoir modeling when using simulation methods based on sedimentary microfacies control. When the abnormal data are truncated and the reservoir properties probability distribution fits a normal distribution, microfacies-controlled reservoir property models are more reliable than those obtained from the sequence Gauss simulation method. The cutoffs for effective porosity of the debris channel, fan lobe, and natural levee facies were 0.2, 0.09, and 0.12, respectively; the corresponding average effective porosities were 0.24, 0.13, and 0.15. The proposed modeling method makes full use of seismic attributes and seismic inversion data, and also makes the property data of single-well depositional microfacies more conformable to a normal distribution with geological significance. Thus, the method allows use of more reliable input data when we construct a model of a sandy debris flow.     

Assessment of Geological Security and Integrated Assessment Geo‐environmental Suitability in Worst‐hit Areas in Wenchuan Quake

Abstract: The Wenchuan earthquake in 2008 and geo-hazards triggered by the earthquake caused large injuries and deaths as well as destructive damage for infrastructures like construction, traffic and electricity. It is urgent to select relatively secure areas for townships and cities constructed in high mountainous regions with high magnitude earthquakes. This paper presents the basic thoughts, evaluation indices and evaluation methods of geological security evaluation, water and land resources security demonstration and integrated assessments of geo-environmental suitability for reconstruction in alp and ravine with high magnitude earthquakes, which are applied in the worst-hit areas (12 counties). The integrated assessment shows that: (1) located in the Longmenshan fault zone, the evaluated area is of poor regional crust stability, in which the unstable and second unstable areas account for 79% of the total; (2) the geo-hazards susceptibility is high in the evaluation area. The spots of geo-hazards triggered by earthquake are mainly distributed along the active fault zone with higher distribution in the moderate and high mountains area, in which the areas of high and moderate susceptibility zoning accounts for 40.1% of the total; (3) geological security is poor in the evaluated area, in which the area of the unsuitable construction occupies 73.1%, whereas in the suitable construction area, the areas of geological security, second security and insecurity zoning account for 8.3%, 9.3% and 9.3% of the evaluated area respectively; (4) geo-environmental suitability is poor in the evaluated area , in which the areas of suitability and basic suitability zoning account for 3.5% and 7.3% of the whole evaluation area.     

Quantitative Geoscience and Geological Big Data Development: A Review

After long-term development, mathematical geology has today become an independent discipline. Big Data science, which has become a new scientific paradigm in the 21 st century, gives rise to the geological Big Data, i.e. mathematical geology and quantitative geoscience. Thanks to a robust macro strategy for big data, China’s quantitative geoscience and geological big data’s rapid development meets present requirements and has kept up with international levels. This paper presents China’s decade-long achievements in quantitative prediction and assessment of mineral resources, geoscience information and software systems, geological information platform development, etc., with an emphasis on application of geological big data in informatics, quantitative mineral prediction, geological environment and disaster management, digital land survey, digital city, etc. Looking ahead, mathematical geology is moving towards "Digital Geology", "Digital Land" and "Geological Cloud", eventually realizing China’s grand "Digital China" blueprint, and these valuable results will be showcased on the international academic arena.     

Effect of Uncertainty of the Pre-Exponential Factor on Kinetic Parameters of Hydrocarbon Generation from Organic Matter and its Geological Applications

The source rock sample of the Shahejie Formation（upper Es₄） in Jiyang Sag was pyrolyzed under open system with the Rock-Eval-Ⅱapparatus,and then kinetic model parameters were calibrated for investigating the effect of uncertainty of pre-exponential factors on kinetic parameters and geological applications,where the parallel first-order reaction rate model with an average pre-exponential factor and discrete distribution activity energies was used.The results indicate that when the pre-exponential factor changes from low to high,an extreme value for residual errors occurs.And with the increasing pre-exponential factor,the distribution shape of activation energies are nearly the same,but the values of activation energies move higher integrally,and the average activation energy increases about 12 kJ/mol for every 10-fold of the pre-exponential factors.Extrapolating the geological heating rate of 3.3℃/Ma,the results show that with the increases in pre-exponential factor, the geological temperature corresponding to TR_0.5（transforming ratio of hydrocarbon generation is 50%） increases gradually,and the additional temperature gradually decreases.Combined with geochemical data of source rock,the kinetic parameters with different pre-exponential factors are used to calculate the transformation ratio of hydrocarbon generation,and the result indicates that kinetic parameters corresponding to the better optimized pre-exponential factor are more suitable.It is suggested that the risk assessment of hydrocarbon generation kinetic parameters should be enhanced when using the kinetic method to appraise the oil-gas resources.Meantime,the application result of different kinetic parameters should be verified with geological and geochemical data of source rock in the target area;therefore,the most suitable kinetic parameters for target can be obtained.     

工程地质空间多场耦合构模技术研究

现有的三维地质模拟技术没有考虑地质空间几何结构场与属性参数场之间的耦合关系,从而限制了计算机模拟结果的真实性和实用性。工程地质空间多场耦合构模问题已成为制约三维地质模拟技术深入发展应用的瓶颈。在综合国内外研究现状与发展趋势的基础上,提出了工程地质空间多场耦合构模的总体研究框架和基本工作流程,给出了研究过程中所遇到的主要科学问题的解决思路或实现方案,并通过实例说明地质体多场耦合模型在三维地质建模及可视化系统中初步实现后的效果。这些研究成果为建立一套完整的地质体多场耦合构模理论体系和方法体系奠定了基础,有助于推动工程地质数字化建模分析技术的深入应用。     

江西相山火山盆地三维地质建模的实践与思考

三维地质建模是在地质体空间结构分析的基础上,运用计算机技术,建立可供展示、编辑、计算和输出于一体的数据模型。在江西相山地区地表数字地质填图、深部地球物理勘探、钻探数据分析的基础上,依托GOCAD软件平台建成了5个不同范围、不同数据源的三维地质模型,探索了数字地质填图建模、地质剖面建模和多源数据融合建模3种建模方法。其中数字地质填图建模是很有推广价值的三维建模方法,可以作为地表区域地质填图的一种新型表达方式,也可以作为一种过渡性模型,用作更深层次三维地质调查的工作部署基础和建模约束条件。三维地质建模强调多源数据的有机融合与相互印证,需要地质、物探、信息技术多学科融合,在3D空间里理解所有地质体、地质现象的几何形态和成因关系。     

固体矿产资源智能采矿关键技术研究

智能采选矿技术是当今矿山建设、矿产开采的重要方向,是国家能源开发的战略核心之一,也是未来深部固体矿产井下自动化无人开采的关键技术。本文针对传统采矿技术在矿山规划建设及环境保护、采矿技术操作及生产安全等方面存在的问题,以现有先进的地质找矿基础理论、三维可视化地质建模技术、随钻测量与定向钻井技术、水力采矿和气举反循环钻进技术等为基础,通过相关技术的集成创新,提出了一项基于GGD(Geology、Geophysics、Drilling)的固体矿产资源智能采矿技术全新理念,并阐述了其可行性和工业化应用的基本解决方案。上述技术的应用将会带来大型矿山机械设计制造业和采矿业产业结构的深度变革。     

基于线框架模型的三维复杂地质体建模方法

提出了一种基于线框架模型的复杂地质体三维建模方法,在准确表达复杂地质体各要素空间几何形态与相互关系的基础上,实现地层交错情况下断层面、地层面模型及复杂地质体模型的准确快速构建.建模实践表明:基于线框架模型的复杂地质体三维建模方法是准确高效的,能适应常见复杂地质条件下三维复杂地质体模型的构建.     

三维地质建模过程中综合地质剖面构建方法研究

综合地质剖面是三维地质建模重要的数据源,在地质构造复杂地区运用综合地质剖面构建三维地质模型的方法应用较为广泛。本文以成都市为例,详细介绍了综合地质剖面构建需要准备的地质资料、剖面的部署原则和构建方法,并解决了剖面构建过程中遇到的同时代、同层位的不同地层之间的连接问题。实践表明,通过综合地质剖面的构建,可以充分发挥地质技术人员在三维地质建模中的主观能动性,准确刻画复杂地质体在三维空间的展布情况,有效实现复杂地质体交互式半自动建模,提高三维地质建模的效率和精准度。     

基于多源数据和先验知识约束的复杂地质体三维建模研究

三维地质模型可以直观的展现地下地质情况,对传统地矿行业的转型升级和城市规划建设都具有重要意义。针对复杂地质条件下三维模型的构建,笔者等提出了一种基于多源数据和地质先验知识约束的三维地质建模方法。以成都市为例,基于MapGIS10.0 软件三维地学建模模块,在DEM数据、数字地质图、综合地质剖面图、钻孔数据、物探解译数据、构造纲要图等多源数据,以及地质体展布形态、产状和厚度变化,断层性质、延伸方向、产状变化、对地质体的错切,褶皱类型、形态特征、两翼产状变化等地质先验知识的共同约束下,开展复杂地质条件下三维地质模型构建研究。笔者等详细介绍了复杂地质体三维建模数据源的准备、建模流程与方法、模型的构建与可靠性分析。认为采用分块建模技术可有效降低复杂地质体三维模型构建的难度,提高建模效率,实现模型的无痕拼接,且易于后期模型的修改完善。本次基于多源数据和地质先验知识约束,采用分块建模技术首次构建了成都市三维地质模型。笔者等通过地质先验知识（地质规律）和静态数据（可视化和抽稀钻孔数据）对模型的可靠性进行了分析,其中抽稀钻孔数据分析采用未参与建模的真实钻孔对三维地质模型中地质体埋深和分层厚度进行误差计算,获得地质体埋深误差均值为33.15 m,分层厚度误差均值21.37 m,认为模型的可靠性较高,可为成都市城市规划和重大工程选址提供重要的基础地质数据支撑。     

基于多源数据和先验知识约束的复杂地质体三维建模研究

三维地质模型可以直观的展现地下地质情况,对传统地矿行业的转型升级和城市规划建设都具有重要意义。针对复杂地质条件下三维模型的构建,笔者等提出了一种基于多源数据和地质先验知识约束的三维地质建模方法。以成都市为例,基于MapGIS10.0 软件三维地学建模模块,在DEM数据、数字地质图、综合地质剖面图、钻孔数据、物探解译数据、构造纲要图等多源数据,以及地质体展布形态、产状和厚度变化,断层性质、延伸方向、产状变化、对地质体的错切,褶皱类型、形态特征、两翼产状变化等地质先验知识的共同约束下,开展复杂地质条件下三维地质模型构建研究。笔者等详细介绍了复杂地质体三维建模数据源的准备、建模流程与方法、模型的构建与可靠性分析。认为采用分块建模技术可有效降低复杂地质体三维模型构建的难度,提高建模效率,实现模型的无痕拼接,且易于后期模型的修改完善。本次基于多源数据和地质先验知识约束,采用分块建模技术首次构建了成都市三维地质模型。笔者等通过地质先验知识（地质规律）和静态数据（可视化和抽稀钻孔数据）对模型的可靠性进行了分析,其中抽稀钻孔数据分析采用未参与建模的真实钻孔对三维地质模型中地质体埋深和分层厚度进行误差计算,获得地质体埋深误差均值为33.15 m,分层厚度误差均值21.37 m,认为模型的可靠性较高,可为成都市城市规划和重大工程选址提供重要的基础地质数据支撑。     

复杂断裂构造条件下城市地质三维建模方法研究

三维地质建模技术是城市地质应用中的一个前沿课题。三维模型的准确程度对于工程分析、判断和决策影响极大。常规的三维地质建模方法通过大量简化地质条件来降低建模的复杂度,却无法精确描述断层等复杂而特殊的地质现象。笔者以构造条件复杂、断裂发育的沉积盆地为研究对象,对复杂断裂构造条件下城市地质三维建模中的关键技术和建模方法进行了探索性研究,形成了一套以地质构造框架为单元,以岩层出露线和岩层产状作为岩层的形态要素,钻孔数据作为层面的控制要素,形成一套由面成体的“构造镶嵌”地质建模的技术方法流程。关中盆地第四纪三维地质建模实例证明,该方法可以有效地提高复杂断裂条件下三维地质建模的效率与准确性,可为地质条件复杂地区的城市地质调查项目提供借鉴。     

三维地质建模及可视化系统的设计与开发

三维地学模拟是三维地质信息GIS可视化的核心内容。基于基础GIS软件平台MAPGIS,利用功能强大的三维可视化开发平台MAPGIS-TDE,设计、开发具有自主版权的三维地质建模及可视化系统。MAPGIS-TDE包括MAPGIS内核模块、MAPGIS-TDE基础平台、MAPGIS-TDE构建平台和基于MAPGIS-TDE的应用系统等4个层次。基于MAPGIS-TDE的三维地质建模及可视化系统分为地质数据管理、二维地质分析、地质断面处理、地质结构建模和地质属性建模等5大功能模块。系统实现时,将空间数据库划分为基础地理图形库、区域地质数据库、工程地质数据库、水文地质数据库、地球物理数据库、地球化学数据库等6类。该系统不仅提供了强大的地质数据管理、三维地质建模以及模型的可视化功能,还为专业技术人员提供了一个可视化的分析、设计平台。     

基于多源数据的三维地质建模——以东莞市滨海湾新区为例

由于地质结构的复杂性、地质数据的多源异构性,复杂地质体的快速自动化建模一直是三维地质建模领域的研究难点。本文以东莞市滨海湾新区为例,使用MAPGIS 10.0 软件,采用基于多源数据约束的钻孔自动建模和基岩产状下推建模融合的建模方法,并在区域分界面-基岩顶面的约束下实现第四系地质体与基岩地质体的无缝拼接,实现了复杂层状地质体的快速自动构建。对于建模区域第四系地质体的构建,采用针对层状地质体建模的多源数据约束钻孔自动建模方法,以钻孔为基础数据,采用不规则三角网构建第四系地质界面,同时加入地质剖面、地质图、数字高程模型等多源数据作为约束,弥补了钻孔分布的不均匀性,使建立的模型更加符合实际地质情况。对于浅层基岩地质体的构建,使用基于基岩地质图、断层和产状信息的基岩产状下推建模方法,在保证建模效果的前提下,提高了建模效率和自动化程度,并能准确地反映断层等地质现象。计算的实际孔与模型孔的地层厚度差值表明构建的三维地质模型精度较高,可为东莞市滨海湾新区城市地质工作提供重要的基础数据支撑。