Influence of underground space development mode on the groundwater flow field in Xiong’an new area

The degree and scale of underground space development are growing with the continuous advancement of urbanization in China. The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation. This paper took the key development zone of the Xiong’an New Area as the study area, and used the Groundwater modeling system software (GMS) to analyse the influence on the groundwater flow field under the point, line, and surface development modes. The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer. The groundwater level on the upstream face of the underground structure would rise, while the water level on the downstream face would drop. The “line” concurrent development has the least impact on the groundwater flow field, and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m. The “surface” development has the greatest impact on the groundwater flow field, and the maximum rise of water level is expected to be 7.17 m.     

锂的圈层循环与资源富集过程: 从高原盐湖到造山带伟晶岩

盐湖卤水型锂矿与富锂伟晶岩是目前最为主要的可利用锂资源, 前者是经地表风化/高温水岩淋滤形成的水体通过蒸发作用浓缩而成的卤水, 而后者被认为是陆表风化沉积物熔融产物经高演化形成的富锂硬岩。大陆地壳是此类表生物质循环最根本的物源, 因而探究富锂地壳的形成及其表生风化剥蚀对于理解盐湖与伟晶岩锂成矿至关重要。本文将从元素循环视角切入, 结合内生高温-外生低温过程中锂的元素地球化学行为, 梳理锂在俯冲带各圈层的循环过程, 探讨富锂地壳的形成机制及其对高原盐湖与造山带伟晶岩锂资源发育的影响。研究发现: (1)俯冲板片对弧岩浆锂的物质贡献有限; (2)厚地壳环境下的弧岩浆具有更高的锂含量; (3)造山带富锂弧岩石的循环应是盐湖与伟晶岩锂成矿的重要控制因素。

     

冕宁-德昌稀土成矿带碳酸岩流体研究

通过对四川冕宁-德昌稀土矿带主要矿物中包裹体岩相学、显微测温分析与包裹体成分分析,指出由岩浆碳酸岩分异出的成矿流体为富含高密度CO2、K、Na、SO42-和多种成矿元素的超临界流体,流体以高温、高压、超高盐度、富CO2为特征,从早期到晚期流体中CO2含量增加。结合前人对碳酸岩流体、稀土矿带周边新生代盆地中无机成因CO2气藏、富钾卤水、稳定同位素和隋性气体同位素研究成果,从碳酸岩流体的性质、流体体系、碳、氦同位素组成,初步探讨了碳酸岩流体与周边新生代盆地中CO2气藏、富钾卤水的成因联系。     

落马洞暗河发育特征及其洪涝成因分析

根据区域岩溶发育史分析认为,湖北宣恩县落马洞暗河的形成总体上可分为两个阶段:第一阶段发生在白垩纪末至晚第三纪。在该阶段中,降水主要通过发育于卧西坪岩溶坡立谷地两侧的小型洼地、落水洞汇入地下管道,往卧西坪谷地排泄,在卧西坪一带形成一小型岩溶湖泊的同时,还在谷地西侧形成了下黑槽、铜锣坪、扁洞三个近东西向地下暗河系统。第二个阶段发生在晚第三纪至今。在这一期间,随着区域构造运动的振荡性抬升,岩溶侵蚀基准面不断下降,在谷地内形成了上、下黑槽、铜锣坪落水洞与卧西坪消水洞等垂向岩溶管道,贯通早期形成的东西向管道并袭夺卧西坪和铜锣坪一带的地表岩溶湖水,使得原分散的岩溶水系统通过南北向的主管道集中排泄,形成了多进口的树枝状复杂管道暗河系统。卧西坪岩溶坡立谷内常年遭受洪涝的原因主要是由于落马洞地下暗河形成年代较晚,管道规模较小,且洞内坍塌淤积严重,排水能力小。在此基础上,提出了加强流域水土流失管理、疏通河道和新建排水隧洞等治理措施与防治对策。      

柴达木盆地西部地下卤水水化学特征及其起源演化

柴达木盆地西北角分布有基岩,盆地西部分布山麓堆积及河、湖相沉积地层,新生界发育有多个北西—南东走向的规模不一的背斜,新近系分布有富钾地下卤水。利用统计方法分析卤水中TDS、K+和B2O3的富集情况。结果显示：TDS值出现双峰,卤水样品富K+和B3+的概率分别为628%和6129%。使用Piper图研究地下卤水时,经常出现样品点过于集中而不易反映主要离子含量的变化。本次研究改进了前人的图示方法,绘制适合于表示地下卤水的水化学图。利用钠氯系数、氯溴系数、氯碘系数、钾氯系数、脱硫系数、钙镁系数对研究区卤水水样进行分析,结果显示卤水样品多数未达到石盐沉积,少数达到石盐沉积。研究区水样氢、氧稳定同位素数据显示新近系地下卤水δ18O值和δD值均发生漂移,表明卤水经历长时间的蒸发浓缩。研究区地下卤水起源于早上新世的古大气降水,上新世以后由于青藏高原快速隆升,柴达木盆地抬升和沉降中心东移,接受沉积形成良好的盖层,同时大气环流的改变致使气候变得干燥,地下卤水经历蒸发浓缩封存,形成现今的卤水。     

基于COMSOL的地下水封油库围岩流固耦合特征模拟研究

地下水封油库通常建造于完整性好的结晶岩体内部,利用隙存水封的原理将油气封闭于地下洞室内部,洞库围岩在施工及运营期间具有典型的流固耦合特征。论文基于裂隙岩体流固耦合理论,采用COMSOL Multiphysics 软件对洞库围岩不同工况下流固耦合特征进行了模拟研究。研究结果表明:地下洞库在不设置人工水幕情况下,开挖后洞室顶部地下水位明显下降,并形成降落漏斗,可能导致洞室油气外溢; 设置人工水幕后,洞室顶部地下水位下降趋势得到明显控制,有效确保了水封的可靠性; 在设置水幕的情况下,洞室直墙及洞室拱顶与底板角点处出现明显的应力集中,但围岩仍未出现连贯塑性区,洞室最大位移不超过5mm,洞室围岩稳定性良好。分析成果对于指导洞库优化设计及施工具有一定的参考价值。     

柴达木盆地一里坪盐湖富锂卤水特征、储层物性及富水区分析

一里坪盐湖是柴达木盆地中一个典型的富锂卤水矿床,具有重大的经济价值。本文以查明盐湖深部卤水分布为目的,从卤水储层的空间分布特征和储层物性的角度对富水区进行预测,为卤水开发提供依据。研究区位于一里坪成盐盆地沉积中心区域,晚更新世末期以来,以沉积浅湖相的含淤泥和黏土粉砂岩,盐湖相的含粉砂和黏土的石盐岩为特征。在垂向上,由上下两套石盐岩夹中部粉砂岩组成一里坪富锂卤水的储层;平面上,研究区北部主要为浅湖相,往南过渡为盐湖相,石盐岩厚度在东南部最大。对储层厚度、孔隙度和给水度的分析表明,第Ⅱ矿层孔隙型和晶间型卤水优质储层均位于研究区东部,可作为卤水资源勘查开采的重点区域。     

柴达木盆地一里坪盐湖成盐卤水成分变化及其意义 ——来自LA-ICP-MS分析石盐流体包裹体组成的证据

一里坪盐湖是柴达木盆地一个以富锂卤水为主的干盐湖,蕴藏有丰富的卤水钾锂资源,目前对成矿过程中卤水的成分及其演变规律方面的研究较少.论文选取一里坪盐湖中部钻孔HC2105岩芯的石盐为主要对象,利用激光剥蚀-电感耦合等离子质谱法开展了单个石盐原生流体包裹体成分分析,探讨恢复了一里坪盐湖地区晚更新世以来成盐期的古卤水成分.结...     

Hydrachemical Characteristics at the Seismic Stations in Songyuan District,Jilin Province

The hydrochemical types and origins of underground water in Songyuan and vicinity, Liaoning Province were discussed based on the hydrochemical composition, δD and δ¹⁸O. The water samples from eight wells were collected 4 times during 2014 to 2015. The main ion concentrations of water were analyzed with an Ion Chromatography. Isotopic compositions of hydrogen and oxygen were analyzed with the Liquid Water Isotope Analyzer. The mineralization (TDS) of the water ranged from 125.4 mg/L to 19 350.9 mg/L. Values of δD and δ¹⁸O ranged from -71.7‰ to -98.1‰ and from -9.0‰ to -12.5‰, respectively. The isotopic data indicated that the water originated from meteorological precipitation. The chemical compositions of Taolaizhao phreatic water were influenced by the human activity while the other water samples collected from artesian well were less affected by the human activity. Water in Changling, Dongdashi, Taohaotai, Qianan and Ningjiang were characterized by HCO₃-Na with low TDS values. Such chemical types of water with fluctuations of Na⁺, SO42- and δ¹⁸O drift were resulted from dissolving silicate minerals and adding surfactant during oil exploitation. Fresh water in Fuyu well was Cl-Na type, which was influenced by acid injection during oil exploitation. Water in Qianguo well was characterized by Cl-Na type with TDS up to 19 350.9 mg/L, the obvious fluctuations of hydrogen and oxygen isotopes and increasing ion concentrations in the Qianguo well may be caused by the earthquakes that occurred in the sampling duration. The results will provide the background of hydrochemistry, and will be of benefit to monitoring earthquake and certificating seismic-chemical anomalies in the future.     

四川成都盆地某深层富钾卤水的地球化学特征及成因

本文报道了四川成都盆地某深层富钾层卤水的化学组成，氧、氢、硫和硼同位素组成以及２５℃等温蒸发析盐过程中，从卤水中获得的固相物质组成。在此基础上讨论了卤水的成因，认为该卤水是蒸发浓缩的海相卤水、非海相卤水以及埋藏成岩过程中封存卤水对地层中海相蒸发盐溶滤作用形成的混合水。