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   

Distinguishing extensive and intensive properties for meaningful geocomputation and mapping     

Simon Scheider  Mark D. Huisjes 《International journal of geographical information science》2019,33(1):28-54

A most fundamental and far-reaching trait of geographic information is the distinction between extensive and intensive properties. In common understanding, originating in Physics and Chemistry, extensive properties increase with the size of their supporting objects, while intensive properties are independent of this size. It has long been recognized that the decision whether analytical and cartographic measures can be meaningfully applied depends on whether an attribute is considered intensive or extensive. For example, the choice of a map type as well as the application of basic geocomputational operations, such as spatial intersections, aggregations or algebraic operations such as sums and weighted averages, strongly depend on this semantic distinction. So far, however, the distinction can only be drawn in the head of an analyst. We still lack practical ways of automation for composing GIS workflows and to scale up mapping and geocomputation over many data sources, e.g. in statistical portals. In this article, we test a machine-learning model that is capable of labeling extensive/intensive region attributes with high accuracy based on simple characteristics extractable from geodata files. Furthermore, we propose an ontology pattern that captures central applicability constraints for automating data conversion and mapping using Semantic Web technology.  相似文献   

我国红黏土物理力学性能研究现状及展望     

邓绍云 《岩土工程技术》2020,(1):43-47

采用文献综述研究方法,梳理了红黏土研究成果并进行了评述,对红黏土的物理力学性质进行了归纳和总结,对红黏土的性能改良研究成果进行了汇总,指出红黏土的物理力学性能的差异性根源在于微观结构的个性差异存在,红黏土性能改良的困难在于红黏土的水敏性和热敏性,红黏土性能改良的关键在于控制其含水率。最后指出了研究不足在于普适性理论和知识体系没有构建,改良方法和技术探究应该加强,展望了红黏土性能改良的物理—化学—生物耦合作用的机理及复合技术开发和应用的研究。  相似文献   

偏振激光雷达探测大气—水体光学参数廓线   总被引：2，自引：2，他引：0  

周雨迪  刘东  徐沛拓  毛志华  陈鹏  刘志鹏  刘群  唐培钧  张与鹏  王雪霁  任佳炜  金时伟 《遥感学报》2019,23(1):108-115

激光雷达在上层水体垂直廓线的遥感中展现出巨大优势。本文研制了一套高垂直分辨率的实时探测偏振激光雷达,提出了一种基于偏振激光雷达回波信号的反演算法,采用Fernald理论和多次散射原理反演非均匀大气—水体的衰减和退偏光学产品,以高效稳定地处理偏振激光雷达实验数据。展示了一个中国内陆水体激光雷达探测实例,观测到了两次气溶胶积聚现象和一次水体浑浊现象。对实验数据的分析表明,退偏比主要由前向多次散射和后向单次散射产生的退偏两部分组成。当多次散射强度较大时,退偏比的变化主要取决于多次前向散射退偏;反之,则主要依赖于单次后向散射退偏。  相似文献   

冻土机械切削破碎机理的研究进展   总被引：1，自引：1，他引：0  

李龙  周琴  张凯  凌雪  张在兴  李耀 《冰川冻土》2021,43(2):638-649

冻土开挖困难、破碎效率低是高寒地区工程建设、地基施工等面临的技术难题。冻土机械切削破碎是冻土开挖的主要方法,其机理研究是提高冻土破碎效率的前提和基础。首先总结了温度、含水率、围压等对冻土复杂力学特性的影响,进而调研分析了冻土机械切削破碎的典型切削力学模型,发现冻土切削机械破碎模式不仅与冻土力学特性密切相关,也与切削参数和刀具结构直接相关,冻土切削过程中存在着最优的切削前角（30°~60°）,且深切削和浅切削时冻土内部受力方式存在差异也会导致破坏形式的不同;温度、含水率、围压所造成的冻土力学性能变化会直接导致冻土破坏过程和切削破碎机理的改变,冻土强度随着温度降低表现出先升高然后保持稳定的特性,随着含水率升高呈现出先升高后降低的趋势,冻土破碎存在脆性、塑脆过渡及塑性等不同破坏形式。通过系统总结冻土切削破碎机理研究进展,进一步明确了冻土力学性质主要影响因素、变化特点及其切削破坏损伤特征,为冻土机械切削破碎的切削参数和切削具结构优化提供了设计依据。  相似文献   

高寒冻土区生物结皮对土壤理化属性的影响   总被引：1，自引：0，他引：1  

明姣  盛煜  金会军  张泽  杜玉霞 《冰川冻土》2021,43(2):601-609

生物结皮是高寒地区地被层的重要组分之一。其作为地表特殊的结构层,能够改变地表结构及土壤理化属性,从而影响冻土环境。迄今为止,关于青藏高原高寒生态系统中生物结皮对土壤理化属性的影响尚不清楚。以青藏高原高寒冻土区生物结皮为研究对象,初步研究了生物结皮的特征及其对土壤理化属性的影响。结果表明：生物结皮在高寒草甸退化过程中广泛发育,主要以藻结皮为主,其盖度可达37.3%~51.7%,结皮层平均厚度为12.6 mm。由于生物结皮的发育,高寒地区5~20 cm土层粉粒含量有所增加,但差异不显著,而结皮层土壤田间持水量相比于裸地表层（2 cm）增加了10%~40%,结皮层容重较裸地降低了30%;两种类型藻结皮均显著增加了结皮层及其下0~20 cm土层土壤有机质,而深色藻结皮增加了结皮层及其下0~20 cm土层土壤全氮含量,浅色藻结皮仅增加了结皮层土壤全氮含量,对其下0~20 cm土层土壤全氮含量没有显著影响;生物结皮对土壤pH没有显著影响;生物结皮是高寒生态系统植被退化过程中的关键环节。研究结果为揭示生物结皮在高寒生态系统中发挥重要生态功能提供依据。  相似文献   

不同初始饱和度红砂岩冻融后物理力学性质研究          下载免费PDF全文

沈世伟  吴飞  甘霖  姜满 《探矿工程》2021,48(1):120-128

对不同初始饱和度红砂岩冻融循环前后进行物理及力学试验研究,探讨初始饱和度对红砂岩冻融损伤的影响。本文设定红砂岩试样初始饱和度为20%、40%、60%、80%、100%,冻融次数设定为20次,对冻融前后试样分别测定质量、纵波波速以及进行单轴压缩试验。试验结果表明：1）冻融后不同初始饱和度红砂岩的物理性质发生变化,纵波波速降低、质量减小,但变化程度不同;2）随饱和度的增大,试样经冻融后峰值强度和弹性模量均呈降低趋势,但只有饱和度大于60%时,降低趋势较明显。本文研究为寒区隧道及地下工程建设以及岩土地质灾害监测与治理提供理论依据和试验基础。  相似文献   

Quantitative characterization of different coal rank reservoirs permeability based on NMR and X-CT technology     

GUO Guangshang  XING Liren  LI Hao 《中国地质调查》2021,7(6):103-108

With the increasing development of coalbed methane (CBM) field, the quantitative characterization and evaluation of coal reservoir physical properties is becoming more and more important to CBM scale development. In order to solve the limitations of conventional methods for testing coal reservoir physical properties, the authors used the high-tech technologies such as nuclear magnetic resonance technology and CT scanning technology to effectively solve the problems of in-situ and integrity of rock samples and acquire the porosity and permeability. Nuclear magnetic resonance and CT scanning experiments of coal samples were carried out to rapidly obtain the pore type, pore size distribution and connectivity, effective porosity, spatial distribution of pore fissures and other refined coal reservoir physical parameters, based on the samples of middle and low rank coal in Shenfu block and high rank coal in Shizhuangnan block. So a set of quantitative characterization analysis technology that can be applied to coal reservoirs with different coal rank was formed.  相似文献   

Geology and mineralization of the Sanshandao supergiant gold deposit (1200 t) in the Jiaodong Peninsula,China: A review     

《China Geology》2021,4(4):686-719

The Jiaodong Peninsula in Shandong Province, China is the world’s third-largest gold metallogenic area, with cumulative proven gold resources exceeding 5000 t. Over the past few years, breakthroughs have been made in deep prospecting at a depth of 500–2000 m, particularly in the Sanshandao area where a huge deep gold orebody was identified. Based on previous studies and the latest prospecting progress achieved by the project team of this study, the following results are summarized. (1) 3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield, which was previously considered to consist of several independent deposits, is a supergiant deposit with gold resources of more than 1200 t (including 470 t under the sea area). The length of the major orebody is nearly 8 km, with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction. (2) Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined, forming a stepped metallogenic model from shallow to deep level. The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults, the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed. Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure, these sections along the fault plane serve as the target areas for deep prospecting. (3) Thermal uplifting-extensional structures provide thermodynamic conditions, migration pathways, and deposition spaces for gold mineralization. Meanwhile, the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks. This further led to the reactivation of ore-forming elements, which provided rich materials for gold mineralization. (4) It can be concluded from previous research results that the gold mineralization in the Jiaodong gold deposits occurred at about 120 Ma, which was superimposed by nonferrous metals mineralization at 118–111 Ma. The fluids were dominated by primary mantle water or magmatic water. Metamorphic water occurred in the early stage of the gold mineralization, while the fluid composition was dominated by meteoric water in the late stage. The S, Pb, and Sr isotopic compositions of the ores are similar to those of ore-hosting rocks, indicating that the ore-forming materials mainly derive from crustal materials, with the minor addition of mantle-derived materials. The gold deposits in the Jiaodong Peninsula were formed in an extensional tectonic environment during the transformation of the physical and chemical properties of the lithospheric mantle, which is different from typical orogenic gold deposits. Thus, it is proposed that they are named “Jiaodong-type” gold deposits.©2021 China Geology Editorial Office.  相似文献   

2010—2016年江西省暖季短时强降水特征分析   总被引：2，自引：0，他引：2  

付超  谌芸  朱克云  单九生  曾智琳 《气象》2019,45(9):1238-1247

利用江西省2010—2016年5—9月1597个观测站逐小时降水资料对江西省短时强降水进行统计分析。采用REOF将降水场划分为5个区域：赣北南部（Ⅰ区）,抚州市及赣州中部（Ⅱ区）,赣北北部（Ⅲ区）,赣南南部、北部（Ⅳ区）以及赣中西部（Ⅴ区）。短时强降水高频区主要分布在山地及河谷附近,分别为湘赣交界罗霄山脉东侧、武夷山西侧、信江河谷、乐安河谷和昌江河谷。河谷附近短时强降水频次以昌江河谷最高（16.9次/a）,山地附近最高在罗霄山脉东侧（12.6次/a）,极端短时强降水分别位于上饶市东北部山区（3.7次/a）及九岭山南侧的锦江河谷（3.3次/a）。短时强降水主要发生在5月第3候,6、7月第3~4候以及8月第2~3候。Ⅳ、Ⅴ区具有单峰型的日变化特征;Ⅰ、Ⅱ、Ⅲ区具有双峰型的日变化特征。主峰基本集中在下午17时;次峰在上午08—10时。短时强降水对暴雨贡献率基本在40%以上,Ⅰ、Ⅱ区的暴雨天气过程将近一半是由短时强降水贡献的。信江河谷是暴雨雨量中心,但并不是短时强降水雨量中心;昌江河谷与武夷山西麓既是暴雨中心也是短时强降水中心。  相似文献