Estimation of the 3D correlation structure of an alluvial aquifer from surface-based multi-frequency ground-penetrating radar reflection data     

Zhiwei Xu  James Irving  Kyle Lindsay  John Bradford  Peimin Zhu  Klaus Holliger 《Geophysical Prospecting》2020,68(2):678-689

Knowledge about the stochastic nature of heterogeneity in subsurface hydraulic properties is critical for aquifer characterization and the corresponding prediction of groundwater flow and contaminant transport. Whereas the vertical correlation structure of the heterogeneity is often well constrained by borehole information, the lateral correlation structure is generally unknown because the spacing between boreholes is too large to allow for its meaningful inference. There is, however, evidence to suggest that information on the lateral correlation structure may be extracted from the correlation statistics of the subsurface reflectivity structure imaged by surface-based ground-penetrating radar measurements. To date, case studies involving this approach have been limited to 2D profiles acquired at a single antenna centre frequency in areas with limited complementary information. As a result, the practical reliability of this methodology has been difficult to assess. Here, we extend previous work to 3D and consider reflection ground-penetrating radar data acquired using two antenna centre frequencies at the extensively explored and well-constrained Boise Hydrogeophysical Research Site. We find that the results obtained using the two ground-penetrating radar frequencies are consistent with each other, as well as with information from a number of other studies at the Boise Hydrogeophysical Research Site. In addition, contrary to previous 2D work, our results indicate that the surface-based reflection ground-penetrating radar data are not only sensitive to the aspect ratio of the underlying heterogeneity, but also, albeit to a lesser extent, to the so-called Hurst number, which is a key parameter characterizing the local variability of the fine-scale structure.  相似文献   

Evaluation of clayed silt properties on the behavior of hydrate production in South China Sea     

《China Geology》2020,3(3):362-368

Gas hydrate is one kind of potential energy resources that is buried under deep seafloor or frozen areas. The first trial offshore production from the silty reservoir was conducted in the South China Sea by the China Geological Survey (CGS). During this test, there were many unique characteristics different from the sand reservoir, which was believed to be related to the clayed silt physical properties. In this paper, simulation experiments, facilities analysis, and theoretical calculation were used to confirm the hydrate structure, reservoir thermo-physical property, and bond water movement rule. And the behavior of how they affected production efficiency was analyzed. The results showed that: It was reasonable to use the structure I rather than structure II methane hydrate phase equilibrium data to make the production plan; the dissociation heat absorbed by hydrate was large enough to cause hydrate self-protection or reformation depend on the reservoir thermal transfer and gas supply; clayed silt got better thermal conductivity compared to coarse grain, but poor thermal convection especially with hydrate; clayed silt sediment was easy to bond water, but the irreducible water can be exchanged to free water under high production pressure, and the most obvious pressure range of water increment was 1.9–4.9 MPa.  相似文献   

鄂尔多斯西缘北段的地壳结构和块体间变形关系          下载免费PDF全文

陈一方  陈九辉  郭飚  李顺成  齐少华  赵盼盼  李晓姝 《地球物理学报》2020,63(3):886-896

本文对喜马拉雅计划二期部分台站的远震波形数据进行接收函数提取,利用接收函数共转换点叠加方法获得阿拉善地块、鄂尔多斯地块以及银川—河套盆地下方0~80 km深度的速度间断面结构.结果表明:鄂尔多斯地块成层性好,地壳厚度为38~42 km,康拉德界面为18~22 km,阿拉善地区的Moho面深度为38~45 km.河套盆地地壳厚度约52 km,银川断陷盆地和贺兰山下方的Moho面最深为~55 km.鄂尔多斯西缘构造边界下方Moho面变化明显,且黄河断裂为深大断裂直接切割莫霍界面.根据本文的间断面成像结果我们进一步确定阿拉善地块与鄂尔多斯地块分属不同的大地构造单元.与此同时,我们推测贺兰山以西70~80 km范围内和鄂尔多斯地块西缘北段存在地壳增厚变形的可能.  相似文献   

Research Progress of Geophysical Exploration in Karatungk Mine in Northern Xinjiang, China     

DU Peixiao  LI Yang  WEI Mengyi  HAN Chunming  ZHAO Liang  WU Jing 《中国地震研究》2020,34(3):311-327

Karatungk Mine in northern Xinjiang, China, which is a large-scale magmatic Cu-Ni sulfide mine in the Central Asian orogenic belt, has a long history of mining. The mine is located at the merging belt between Altay orogenic belt and Junggar Basin, and has strong tectonic activities. In recent years, mining source detection has become an important target for mineral exploration due to the difficulties in ore body exploitation. In this paper,we systematically summarize the achievements of the geophysical explorations in Karatungk Mine from various aspects, including tectonic backgrounds of the mine, dynamic mechanisms, geophysical characteristics and scientific challenges in the future. Because of the restrictions of observation density and analysis methods, the fine geometrical structure of the mine cannot be completely characterized yet. Therefore,in order to obtain the high-resolution structure and detailed spatial distribution of orebodies, researchers should focus on combining multiple geophysical methods, developing high-resolution imaging methods, and improving petro physical experiments in the future.  相似文献   

地震作用下相邻地下结构与土相互作用特性研究          下载免费PDF全文

于仲洋  张鸿儒  邱滟佳  李昊 《地震工程学报》2020,42(2):481-489

针对简单框架式地铁车站结构的抗震特性研究已取得一定成果,但对于结构形式较复杂或多个地下结构间相互作用等问题仍需进一步探究。本文利用现有地震分析方法中的动力时程分析法对两个地下结构间相互作用的影响进行系统对比分析,其中主体结构为三层三跨车站、附属结构为两层三跨车站。主要探讨附属结构与主体结构间距离的变化、两结构间连接形式对场地土以及主体结构地震响应特性的影响,分析比较场地土变形、主体结构变形、层间位移角以及内力在不同工况下的地震响应特性。结果表明:相邻地下结构与土相互作用形式较独立结构与土相互作用形式对场地土影响更加明显;当附属结构与主体结构间距离超过两倍结构宽度,附属结构对主体结构周围场地变形影响效应可基本忽略;同样当附属结构与主体结构间距离超过两倍的结构宽度,附属结构对主体结构的变形、内力基本已无影响,因此地震情况下相邻结构间相互作用影响范围基本为两倍结构宽度。与此同时,附属结构的存在对于主体结构抗震特性是不利的,不同连接形式中单层通道连接的形式变形以及内力方面均小于双层通道连接形式。  相似文献   

南海东南部陆缘地壳结构特征及其构造意义          下载免费PDF全文

邱宁  姚永坚  张江阳  王利杰  徐东海 《地球物理学报》2019,62(7):2607-2621

南海东南部海域沉积厚度较大，礁体发育，构造演化复杂，导致深部结构探测不清楚，制约了对南部陆缘地壳结构的认识.本文通过对新采集和重新处理的多道地震剖面解释，结合钻井、拖网资料，对浅部地层和构造进行约束，同时利用附近海底地震（OBS）测线的速度结构，对深部结构和界面解释约束；在此基础上，开展了重震联合反演，分析地壳密度空间分布特征，结合重力梯度特征对构造单元进行识别.通过对东西两条测线的上下和全地壳厚度、拉伸因子比较，发现南海东南部的东西部深部结构存在差异性；礼乐断裂可能是礼乐和郑和地块的分界，并控制了两个地块在南海扩张时期的相对运动.  相似文献   

江汉盆地典型二级构造带特征分析     

卢圣力  赵江  王秋良 《大地测量与地球动力学》2019,39(3):226-230

在三维地震资料的基础上，依据构造带划分原则，把江汉盆地构造带划分为三大类，分别为断裂、盐构造及古潜山，共25个，并分别在3个类别中选取一个典型构造带进行讨论研究。  相似文献   

不同非感应起电及感应起电参数化方案对青海东部一次雷暴云电荷结构影响的数值模拟研究          下载免费PDF全文

李江林  余晔  李万莉  李亚珺 《地球物理学报》2019,62(7):2366-2381

本研究利用加入起电、放电参数化方案的数值模式（Weather Research and Forecasting Model（Version 3.7.1），WRF3.7.1_ELEC），通过设计五组不同非感应起电及感应起电参数化方案敏感性试验，对发生在青藏高原东北部青海大通地区的一次雷暴过程进行模拟研究，对比分析了不同非感应起电机制及感应起电机制对雷暴云电荷结构的影响.结果表明：在雷暴云发展旺盛阶段，Saunders（S91）、Riming Rate（RR）、和Saunders和Peck（SP98）三种非感应起电方案模拟的雷暴云最低层均为负电荷区，而混合方案（Brooks and SP98，BSP）模拟的雷暴云最低层为正电荷区，主电荷区自下而上为"+-+-"排列的四层电荷结构.与甚高频辐射源定位法推算的结果对比，BSP方案模拟的本次高原雷暴云电荷结构更接近实际情况；几种不同非感应起电方案模拟的主电荷区外围与主电荷区电荷结构不同，说明在雷暴发展的不同阶段雷暴云的电荷结构是不同的；几种非感应起电方案模拟的电荷结构不尽相同，主要是由于霰、冰和雪粒子在不同高度所带电荷的极性及电量的大小不同，霰粒子的电荷密度对低层的影响较大，冰粒子和雪粒子的电荷密度对中上层的影响较大；加入感应起电机制后，雷暴云电荷结构分布几乎没有变化，但能使雷暴云发展旺盛阶段低层和中层的正负电荷区电荷密度有所加强.  相似文献   

新疆天山地区壳幔S波速度结构特征及变形分析   总被引：1，自引：0，他引：1       下载免费PDF全文

蔡妍  吴建平  明跃红  房立华  王未来  孔祥艳  杨婷  范莉苹 《地球物理学报》2019,62(11):4214-4226

天山地区地质构造复杂，地震活动频繁，其壳幔变形和深部结构一直受到学者们的高度关注.然而，由于天山地区地震台站资料较少，致使壳幔变形研究结果与解释存在诸多争议.本研究利用在天山地区（40°N-46°N，78°E-92°E）新布设的11个流动宽频带地震台站和该地区39个固定台站的观测资料，采用接收函数与面波联合反演方法，获得了研究区地壳厚度及壳幔S波速度结构.反演结果显示天山地区（41.5°N-44°N，78°E-88°E）平均地壳厚度为56 km，塔里木盆地（40°N-41.5°N，79°E-90°E）、准噶尔盆地（44°N-46°N，82°E-90°E）和吐鲁番盆地（42°N-43°N，88°E-90°E）具有较厚的沉积层，地壳平均厚度为43 km、53 km和46 km，整体表现为天山厚、盆地相对较薄的特征；在研究区南天山的最高峰（42°N，80.5°E）及北天山的最高峰（43.5°N，86°E）附近，中下地壳存在较厚的低速层，我们认为在强烈挤压作用下低速、低强度的中下地壳强烈变形可能是导致该区域快速隆升的主要原因.在研究区中部，位于塔里木盆地与准噶尔盆地之间的天山地区，中下地壳及上地幔均存在低速层，且盆地莫霍面向天山倾斜明显.结合前人的研究成果推测，在南北向构造挤压应力作用下，塔里木盆地与准噶尔盆地发生了向天山造山带方向的双向壳幔层间插入俯冲.在研究区东部，塔里木盆地东北缘与天山东部接触带的地壳内没有明显的低速层，推测应处在早期挤压变形状态，该区域的壳幔边界为缓变的速度梯度带，可能与上地幔热物质侵入或渗透有关.  相似文献   

琼东南盆地深水区松南-宝岛凹陷反转构造带发育特征及油气地质意义   总被引：1，自引：1，他引：0  

杨金海  杨希冰  周杰  甘军  宋爱学  江凡  杨璐 《海洋学报》2019,41(5):97-106

利用新三维地震资料对松南-宝岛凹陷反转构造带发育特征、形成期次进行研究，并从构造背景及力学机制两个方面探讨反转构造的成因机制。研究结果表明，松南-宝岛凹陷反转构造带主要发育一系列"上凸下凹"的大型褶皱背斜，伴生NWW向弱走滑断裂构造和NNW向张剪构造。反转构造及其伴生构造符合NEE右旋剪切应力场特征，形成时间与东沙运动一致，表明该反转构造带可能受晚中新世南海东北部东沙运动产生的右旋走滑应力场作用控制。反转构造有利于研究区圈闭的重建和改造，对琼东南盆地东部新区油气运移和重新优选分配的认识，具有重要的油气地质意义。  相似文献