基于BERT的三维地质建模约束信息抽取方法及意义

地质报告中地质体的几何、拓扑及属性信息是三维地质建模过程中重要约束性信息。但传统的属性信息抽取方法存在覆盖率有限、局限于人工设计特征及模型泛化能力差等问题。面向三维建模任务,总结了地质报告中地质体的几何、拓扑及属性文本的特点,提出了一种基于BERT-BiLSTM-CRF的三维地质建模信息抽取方法;基于BERT预训练模型,构建融合BiLSTM和CRF的深度学习模型,通过BERT模型获取动态字符深层次语义信息,弥补静态词向量无法解决一词多义的问题,提高地质体复杂建模信息的抽取能力。以43篇地质报告为数据源进行模型性能评估,实验结果表明所提出的方法对于地质体三类属性信息抽取准确率达到90%以上,对于三维地质建模具有重要支撑作用。     

基于支持向量机的矿化蚀变信息提取研究——以青海黄南州吉地地区为例

支持向量机(SV)M引入遥感图像处理领域并逐步得到推广,但在遥感地质应用中则刚刚起步。本研究运用SVM提取矿化蚀变信息,选择青海黄南州吉地地区作为典型研究区,首先选取训练样本,然后求解最优超平面(即找出支持向量),进而确定决策函数,最后泛化推广识别其它待识别的样本。矿区叠加研究和野外实地验证表明SVM提取矿化蚀变信息克服了传统的统计方法需要大量样本的缺陷,保证了矿化信息提取的精度。最后,指出了三个重点异常区。     

利用目标向量空间变换方法提取含矿岩层的研究——以新疆卡特里西地区为例

多因子线性变换是处理多波段遥感数据的数学方法,应用该方法对于图象主要特征的分离和提取具有很好的效果.但是,遥感图象数据中的岩性信息光谱分布复杂多样,在信息强度和分布方面较弱,使用现有的变换很难将岩性信息提取出来.为了完成遥感岩性填图的任务,本文提出利用目标向量空间线性变换的方法,简化所要提取的目标信息的光谱结构,提取目标信息.根据研究区内岩性目标地物的图象灰度光谱分布选择空间域坐标轴的位置,使需要分离的岩性信息只在一个轴上的投影不为0,从而将岩性目标信息分离出来.该方法在新疆且末卡特里西地区提取铜矿带岩性取得了较好的结果.     

基于随机森林模型的城市不透水面提取研究 ——以呼和浩特市为例

城市不透水面信息对于城市生态环境动态演化过程研究具有重要意义。以Landsat 8遥感影像为数据源,以呼和浩特市为实证区域,进行了随机森林模型应用于城市不透水面的提取研究,并与目前应用广泛的支持向量机模型进行了对比分析。研究表明：在不同的抽样比例训练样本条件下,随机森林模型对于城市不透水面的提取精度均优于支持向量机的提取精度;对于随机森林模型和支持向量机模型,70%的训练样本比例均为最佳训练样本抽样比例。在该抽样比例下,随机森林模型提取城市不透水面的总体分类精度为93.29%,Kappa系数为0.9051,支持向量机模型的总体分类精度为91.26%,Kappa系数为0.8757;随机森林模型对于城市裸土的识别度较高,能更好地将城市裸土和不透水面进行区分,而支持向量机模型对于城市裸土、不透水面和绿地的区分能力均弱于随机森林模型。综合而言,随机森林模型对城市不透水面的提取精度优于支持向量机模型,随机森林模型可以有效应用于城市不透水面提取领域,进一步丰富了城市不透水面提取方法体系构成。     

基于PCA法向量估计与RANSAC算法的隧道中轴线提取

为了减少隧道点云噪声对隧道中轴线提取精度的影响,提出主成分分析(PCA,Principal Components Analysis)算法点云法向量估计与随机抽样一致性(RANSAC,Random Sample Consensus)算法相结合的隧道中轴线提取方法。首先对隧道点云数据进行ROI(Region of Interest)区域提取及统计滤波预处理,其次通过PCA算法估计隧道点云法向量并进行点云法向量方向一致化处理,通过设定阈值分别提取满足要求的隧道拱顶及拱腰处法向量,最后用RANSAC算法代替最小二乘算法对筛选出来的法向量提取出精度较高的隧道中轴线。实验结果表明,本文方法所提取出来的隧道中轴线受噪声影响较小,斜率最大偏差0.007 1,最小偏差0.000 3,算法稳定性好,结果精度较高。     

基于NDSI-NDVI特征空间的积雪面积反演研究

积雪是新疆高海拔地区大多数河流的重要补给来源之一, 不仅是春汛期间融雪性洪水灾害和冰冻灾害的直接原因, 在水资源管理、 灾害防治和融雪模拟预报中也扮演着重要角色. 针对目前积雪信息提取方法的优势与不足, 结合二维特征空间理论, 构建积雪信息反演模型, 并与支持向量机提取积雪信息进行精度对比分析. 结果表明: 相比其他积雪信息提取方法, 利用归一化积雪指数(NDSI)和归一化植被指数(NDVI)建立二维特征空间, 且在特征空间基础之上构建的NN模型, 反演新疆北部积雪信息精度较高, 相关系数达0.837, 提取精度优于支持向量机(SVM)方法, 对当地防洪灾害模拟预测、 生态环境保护、 社会经济发展等方面具有一定参考意义.     

南昌地区三维地质模型初探

三维地质体建模能以三维真实感图形的形式形象地表达地质构造的真实形态、特征以及三维空间物性参数分布规律,成为地质信息可视化的发展方向。南昌地区已进行的地质勘查工作,利用积累的成果资料,首次建立南昌地区三维地质模型。由于资料来源的多样性和对红层下伏地层勘查程度的不足,建模数据的提取和处理较为复杂。讨论资料收集、数据提取及处理和建模步骤,为类似条件的地质建模提供方法参考。     

努和廷地区古河道砂岩型铀矿遥感信息提取

本文概述了努和廷古河道砂岩型铀矿的成因及形成机理、介绍了采用遥感数字图像信息增强技术、钻孔资料的三维量化分析等技术,对该地区古河道砂岩型铀矿的成矿环境信息及威古河道信息的提取进行的方法研究与试验。     

Stacking集成策略下的径向基函数曲面复杂矿体三维建模方法

建立三维矿体模型是数字矿山、智慧矿山的基础.针对经典径向基函数曲面重建算法在原始数据稀疏时出现曲面边界自拟合及模型不连续现象,提出了一种集成多种机器学习模型的径向基函数曲面复杂矿体三维建模方法.该方法利用Stacking模型学习矿体轮廓线离散化点云数据的分布特征,建立表征矿体模型几何信息的有向点集;在此基础上提取边界点及法向量,通过Hermite型径向基函数建立隐式场,最后基于行进四面体算法建立三维矿体模型.与轮廓线拼接法、经典径向基函数曲面重建算法、简单克里金插值法相比,该方法能够有效减少曲面边界自拟合现象,减少模型多余孔洞,提高模型的连续性;建立的模型所切轮廓线与原始轮廓线相似度达75.14%,与人工干预程度较高的显式模型相当;在体积表征上与显式模型的差距达到最低.     

基于Beamlet变换的断层识别与线性提取

Beamlet变换在提取图像线性特征方面效果明显.对于三维地震解释,可将地震相干切片视为图像,切片上断层可视为线性信息,利用Beamlet变换可对切片上的断层进行识别和线性提取.笔者首先介绍了Beamlet变换基本原理,以及其在含噪图像线性特征提取中的优势,然后利用Beamlet变换对四川元坝地区的三维地震相干切片进行断层识别和线性特征提取,并对断层线性信息进行统计分析.结果表明,该方法对于小断层和裂隙发育带的解释具有明显优势.     

Integral equation solution for three-dimensional heat transfer in multiple-fracture enhanced geothermal reservoirs

For the prediction of energy production from multiple-fractured geothermal reservoirs, previous models basically focused on the one-dimensional conduction in the rock containing evenly distributed fractures of equal scale. Here, a novel model is described to numerically investigate the three-dimensional heat transfer in geothermal reservoirs with unevenly spaced disc fractures of various sizes including the aperture and radius. In terms of the water flow through each fracture, an approximate analytical solution is obtained on the assumption that the water pressure disturbances, induced by the fracture margin and extraction (injection) operation, at the injection (extraction) well center and at different locations within the injection (extraction) well range were approximately equal. By the integral equation scheme for two-dimensional planar fractures, the three-dimensional problem of heat exchange is simulated without the reservoir discretization. The singular integral is analytically calculated in polar coordinates whereas the nonsingular integrand is numerically estimated by the Gaussian quadrature method in Cartesian coordinates. Compared with the one-dimensional simplification, the three-dimensional heat conduction remarkably alters the prediction of extraction temperature. In addition, the reservoir temperature field is also significantly influenced by the spacings and dimensions of fractures. The present model may be used for the estimation, design, and optimization of a geothermal reservoir.     

新疆哈巴河县阿舍勒多金属矿黄铁矿标型矿物特征研究

黄铁矿是阿舍勒多金属矿床中主要原矿石矿物之一。黄铁矿标型矿物特征的研究不仅直接提供有关矿床形成条件及成因的若干信息,也是论证矿床类型的有力佐证和重要的找矿标志。黄铁矿标型特征研究具有一定的理论和实际意义。     

基于深度学习的山东大尹格庄金矿床深部三维预测模型

在隐伏矿体三维预测中,预测模型的准确性在很大程度上取决于找矿指标对矿化富集部位的指示性。然而,找矿指标容易受到找矿概念模型可靠性和成矿信息提取有效性限制,从而影响预测的准确性。论文以山东大尹格庄金矿隐伏矿体三维预测为例,基于深度学习方法,构建矿床深部隐伏矿体三维预测模型,旨在利用深度网络模型,学习获得对矿化具有显著指示性的找矿指标,提升三维预测的准确性。该方法将三维地质模型及其形态特征转换为适合卷积网络二维图像,采用卷积神经网络实现找矿指标的自动提取,并构建三维地质模型到矿化富集地段的定量关联。利用该方法建立了大尹格庄金矿的三维预测模型,经与几种人工建立找矿指标预测模型的对比分析,表明基于深度学习的预测模型较大地提升了预测准确性。     

永春桃东温泉地震预报效果分析

1986年以来台湾省花莲、菲律宾(?)、福建省南日岛海域及蓬壶发生过几次地震,发震前桃东温泉井的水量、水氡含量均有明显的规律性变化,可作为短期地震预报的重要信息。笔者认为其变因与温泉所处的地质构造及地貌环境密切相关。     

瓦斯抽采钻孔间距优化三维数值模拟量化研究

为了识别钻孔间距对煤层瓦斯抽采的影响及如何实现高效抽采,基于流固耦合模型,建立三维几何模型,使其更接近现场实际,借助COMSOL软件模拟某煤矿钻孔不同间距的瓦斯抽采过程,利用瓦斯压力为0.74 MPa等压面三维立体图使有效抽采区域可视化,通过计算有效抽采区域体积大小,量化分析钻孔间距对抽采效果的影响。结果表明:单一钻孔抽采120 d时,有效抽采半径约为1.5 m;当布置多个钻孔且钻孔间距d为5 m,抽采120 d时,瓦斯压力为0.74 MPa的等压面围绕所有钻孔近似呈圆柱状但向内部凹陷（即出现空白带）;钻孔间距d为2.1、3、4、5、6 m时,有效抽采区域体积V的大小顺序随着时间的增长而改变,抽采120 d时,V_{d=5 m}>V_{d=4 m}>V_{d=3 m}>V_{d=2.1 m}>V_{d=6 m}。综合分析瓦斯压力等压面三维立体图和有效抽采区域体积的大小顺序,确定该矿钻孔的较优间距为4 m。研究提出的以有效抽采半径、叠加效应、三维瓦斯压力等压面的形状及有效抽采区域体积大小为指标的钻孔间距数值计算考察方法,可为煤矿井下钻孔间距优化布置提供参考。      

新疆阿舍勒铜矿的发现与电法勘探

新疆阿舍勒铜矿是一个隐伏的与火山成因有关的大型块状硫化矿床。它的发现是根据地质调查提出的有色金属找矿靶区。通过自然电场法和激发极化法等综合电法勘探发现电异常,经钻探验证,采用地质、物探、钻探、科研综合普查方法密切配合取得的成果。其中电法勘探起到了导向作用。在发现这一隐伏块状硫化矿床的基础上,对矿区及外围进行了瞬变电磁法等电法勘探的新方法、新技术试验研究工作。根据瞬变电磁法获得的成果,结合自然电场法,激发极化法和地质、化探资料进行综合解释推断,提供了可能存在新的隐伏矿床的信息,指出了进一步普查找矿方向,对扩大该区远景具重要意义。     

A Modeling Study of the Potential Water Quality Impacts from In-Stream Tidal Energy Extraction

To assess the effects of tidal energy extraction on water quality in a simplified estuarine system, which consists of a tidal bay connected to the coastal ocean through a narrow channel where energy is extracted using in-stream tidal turbines, a three-dimensional coastal ocean model with built-in tidal turbine and water quality modules was applied. The effects of tidal energy extraction on water quality were examined for two energy extraction scenarios as compared with the baseline condition. It was found, in general, that the environmental impacts associated with energy extraction depend highly on the amount of power extracted from the system. Model results indicate that, as a result of energy extraction from the channel, the competition between decreased flushing rates in the bay and increased vertical mixing in the channel directly affects water quality responses in the bay. The decreased flushing rates tend to cause a stronger but negative impact on water quality. On the other hand, the increased vertical mixing could lead to higher bottom dissolved oxygen at times. As the first modeling effort directly aimed at examining the impacts of tidal energy extraction on estuarine water quality, this study demonstrates that numerical models can serve as a very useful tool for this purpose. However, more careful efforts are warranted to address system-specific environmental issues in real-world, complex estuarine systems.     

Study of 3D Geological Modeling Based on Aeromagnetic Data

With the increasing difficulty of finding the shallow surface deposit and the increasing depth of resources exploration, three-dimensional modeling technology is more apparent in deep prospecting, and its accuracy directly determines the cognitive degree of geological body and metallogenic condition. For this, we put forward a set of the extraction technology of abnormal information combined with aeromagnetic data processing with three-dimensional geological modeling. Inversing the selected profile of the study area and obtaining each profile geological model, we built three-dimensional geological model of geological units by the method of profile linked, using undulating terrain three-dimensional block magnetic field forward techniques to model the three-dimensional geological model of the whole area, and obtained the forward modeling results of the whole three-dimensional geological model and the geological unit. After the comparative analysis with the test result, adding reasonable geological constraints and revising model, through adjusting for many times, we made the model maximum close to the actual situation. The model can well reflect the geological information and make minimum fitting error of observations and theoretical field, with which geologists can use the most of their experience and get more regional geological understanding. Using the thought of main block and secondary block to subdivision modeling of geological body, on the condition of ensuring the accuracy of model, the number of the total model block decreased and the multi-window and multi-geological body parallel computing method were used to improve the modeling speed, effectively solve the limitation problem of the model complexity in the process of the three-dimensional inversion modeling method, and easily form complex and different sizes three-dimensional geological model. We applied this method to the Hubei Daye area, constructed the three-dimensional geological model of Daye Iron Mine, and verified the feasibility and rationality of this method.     

Boundary element analysis of geomechanical fracture

In this paper, a single-region BEM formulation for the three-dimensional analysis of fractures in geomechanics is developed. The technique allows the use of continuous elements in the discretization of the crack surfaces. Intially, an example from earthquake control theory is solved to demonstrated the validity of the technique for partially loaded crack surfaces. The method is then extended to deal with contact between crack surfaces by the incorporation of spring constraints. This allows two futher applications to be studied, one from hydraulic fracture and the other involving extraction of an ore seam. Copyright © 1999 John Wiley & Sons, Ltd.     

Simulation of heat transfer performance using middle-deep coaxial borehole heat exchangers by FEFLOW

Due to its large heat transfer area and stable thermal performance,the middle-deep coaxial borehole heat exchanger (CBHE) has become one of the emerging technologies to extract geothermal energy. In this paper,a numerical modeling on a three-dimensional unsteady heat transfer model of a CBHE was conducted by using software FEFLOW,in which the model simulation was compared with the other studies and was validated with experimental data. On this basis,a further simulation was done in respect of assessing the influencing factors of thermal extraction performance and thermal influence radius of the CBHE. The results show that the outlet temperature of the heat exchanger decreases rapidly at the initial stage,and then tended to be stable; and the thermal influence radius increases with the increase of borehole depth. The heat extraction rate of the borehole increases linearly with the geothermal gradient. Rock heat capacity has limited impact on the heat extraction rate,but has a great influence on the thermal influence radius of the CBHE. When there is groundwater flow in the reservoir,the increase of groundwater velocity will result in the rise of both outlet temperature and heat extraction rate. The heat affected zone extends along with the groundwater flow direction; and its influence radius is increasing along with flow velocity. In addition,the material of the inner pipe has a significant effect on the heat loss in the pipe,so it is recommended that the material with low thermal conductivity should be used if possible.