3D numerical modeling of hydrothermal processes during the lifetime of a deep geothermal reservoir

Understanding hydrothermal processes during production is critical to optimal geothermal reservoir management and sustainable utilization. This study addresses the hydrothermal (HT) processes in a geothermal research doublet consisting of the injection well E GrSk3/90 and production well Gt GrSk4/05 at the deep geothermal reservoir of Groß Schönebeck (north of Berlin, Germany) during geothermal power production. The reservoir is located between ?4050 to ?4250 m depth in the Lower Permian of the Northeast German Basin. Operational activities such as hydraulic stimulation, production (T = 150°C; Q = ?75 m³ h^?1; C = 265 g l^?1) and injection (T = 70°C; Q = 75 m³ h^?1; C = 265 g l^?1) change the HT conditions of the geothermal reservoir. The most significant changes affect temperature, mass concentration and pore pressure. These changes influence fluid density and viscosity as well as rock properties such as porosity, permeability, thermal conductivity and heat capacity. In addition, the geometry and hydraulic properties of hydraulically induced fractures vary during the lifetime of the reservoir. A three‐dimensional reservoir model was developed based on a structural geological model to simulate and understand the complex interaction of such processes. This model includes a full HT coupling of various petrophysical parameters. Specifically, temperature‐dependent thermal conductivity and heat capacity as well as the pressure‐, temperature‐ and mass concentration‐dependent fluid density and viscosity are considered. These parameters were determined by laboratory and field experiments. The effective pressure dependence of matrix permeability is less than 2.3% at our reservoir conditions and therefore can be neglected. The results of a three‐dimensional thermohaline finite‐element simulation of the life cycle performance of this geothermal well doublet indicate the beginning of thermal breakthrough after 3.6 years of utilization. This result is crucial for optimizing reservoir management. Geofluids (2010) 10 , 406–421     

我国三大都市圈城市创新能级体系比较

大都市圈已成为国际经济发展的关键节点,是国际创新的主要支点。我国三大都市圈在我国创新体系中起着至关重要的作用。本文对我国三大都市经济圈内城市创新能力进行测度分析的基础上,对三大都市圈的创新能级体系进行了比较,并应用重力模型,对中心城市创新引力进行测度与比较,分析了三大都市圈内部城市的创新联系。     

李旭旦先生的学术思想和贡献及其他——纪念李旭旦先生诞辰100周年

李旭旦先生是人文地理学家、区域地理学家和地理教育家,毕生致力于地理教育和科学研究,培养了几代地理学人才,桃李满天下。他才思敏捷,知识渊博,治学严谨、执着,有较高的学术造诣。学术上他强调人地协调论和统一地理学,提倡区域研究,致力于地理教育理论的建设,创办《地理知识》杂志,曾任德国《GeoJournal》杂志编委,主编《人文地理学》(中国大百科全书分册)、《人文地理学论丛》、《人文地理学概说》,提出白龙江是我国西部南北地理分界线的科学论断,主张把解决现实问题作为人文地理学的主攻方向,重视野外调查,晚年他提出复兴人文地理学的倡议,把我国人文地理学的发展推向一个新的阶段。他是我国现代人文地理学的奠基人。     

基于演化视角的区域文化观念嬗变与创新研究——以江苏为例

本文首先明晰演化经济学核心概念在文化研究中的内涵,进而构建了一个基于演化视角的区域文化观念嬗变创新的理论分析框架,并运用这一框架,分析了江苏区域文化观念的演化过程。研究表明:区域文化发展变迁是一个演化过程,在这一过程中,遗传、变异、竞争、选择、路径依赖等是关键词和主旋律;源于文化的强大遗传作用,文化发展深深的植根于历史传统;文化变异产生的新奇、创新形成文化发展变迁的根本动力;文化发展以竞争为重要的外部选择机制;文化发展易于产生"路径锁定"。     

中国旅游创新的回顾与展望:基于文献的研究

伴随改革开放30年进程,中国旅游产业不断走向内生驱动、创新发展之路。其在制度体制机制创新、理论创新等理论研究领域以及区域旅游创新、旅游企业创新等实践研究领域取得了初步成绩,但距离西方同类研究仍有较大差距。本文采取文献统计及文献分析法进行研究,揭示其基本特点,对中国旅游的创新研究主要领域进行文献研究综述,总结其研究的增长规律,立足于旅游产业创新研究的国际趋势和中国实际需要,最后对中国旅游的创新研究主要领域进行了展望。     

Modeling fluid flow in a heterogeneous, fault-controlled hydrothermal system

Previous studies have shown that most hydrothermal systems discharging at the land surface are associated with faulting, and that the location, temperature and rate of discharge of these systems are controlled by the geometry and style of the controlling fault(s). Unfortunately, the transport of heat and fluid in fault-controlled hydrothermal systems is difficult to model realistically; although heterogeneity and anisotropy are assumed to place important controls on flow in faults, few data or observations are available to constrain the distribution of hydraulic properties within active faults. Here, analytical and numerical models are combined with geostatistical models of spatially varying hydraulic properties to model the flow of heat and fluid in the Borax Lake fault of south-east Oregon, USA. A geometric mean permeability within the fault of 7 × 10⁻¹⁴ m² with 2× vertical/horizontal anisotropy in correlation length scale is shown to give the closest match to field observations. Furthermore, the simulations demonstrate that continuity of flow paths is an important factor in reproducing the observed behavior. In addition to providing some insight into possible spatial distributions of hydraulic properties at the Borax Lake site, the study highlights one potential avenue for integrating field observations with simulation results in order to gain greater understanding of fluid flow in faults and fault-controlled hydrothermal and petroleum reservoirs.     

Special alloys from remote frontiers of the Shang Kingdom: scientific study of the Hanzhong bronzes from southwest Shaanxi, China

More than 200 bronze objects found in Hanzhong, southwest Shaanxi Province, China, a frontier region of the Shang Kingdom during the Shang dynasty, have been analysed for their composition and microstructure. Forty-three typologically distinct, and probably culturally indigenous, items have been found to be compositionally distinctive as well. This paper presents analytical results of the two types of local Hanzhong bronzes, namely the sickle-shaped and sceptre-shaped objects. Three special alloys, arsenic bronze, antimonial bronze and copper–nickel–arsenic ternary alloy, are particularly emphasized and discussed. The archaeological context of Hanzhong bronzes and their significance for the archaeometallurgy research of the Shang period are discussed as well.     

Hydrology of the combination irrigation system in the Wadi Faynan, Jordan

The field system of the Wadi Faynan in southern Jordan was fed by an ancient combination irrigation system that incorporated runoff farming and diversion irrigation techniques. The hydraulic characteristics of this system were most probably designed to take advantage of the confluence of three tributary streams. A theoretical model of discharge produced by runoff is based on contemporary ground conditions and historic climate reconstructions. The design principles of the main hydraulic features are examined and velocity and discharge measurements in principal conveyance irrigation channels are reconstructed. The design of this hydraulic system took into account the environmental constraints and opportunities of the area and maximized different sources of water in the catchment using various techniques of water collection.     

Scale, causality, complexity and emergence: rethinking scale's ontological significance

Scale remains a pivotal yet highly contentious concept in geography. I survey the lively discussions engaged in recently by many critical/radical geographers regarding the theoretical status of scale. While these discussions have been intellectually fruitful, I argue that much more needs to be said. Drawing from complex systems theory, I argue that scale should be understood as an ontological category essential to understanding causality. Revalorising Aristotle's four categories of cause – formal, final, material and efficient – from two centuries of positivist thinking facilitates this endeavour. Research on the relationship between university-based poultry scientists and the poultry industry illustrates the explanatory potential of poly-scalar analysis.     

Transnational regional development in the Netherlands and Northwest Germany, 1500–2000

This article discusses the relationship between global development and local changes and also analyzes long-term regional development in the Netherlands and Northwest Germany. Spatial patterns of population growth over the period of 1500–2000 are interpreted from a world-systems perspective. Initially, the coastal regions profited from the emerging trade-based agricultural world-system. Later, state formation enabled some of the previously developed regions to regain positions that were formerly lost. A seesaw of development between land and sea-based regions characterized the first two periods of the world-system. An additional seesaw between concentration in national cores and expansion toward the periphery characterizes the last two periods.