羊八井和腾冲高温岩体地质特征比较与优先选址

高温岩体地热资源开发是解决未来能源问题的重要途径。我国高温岩体地热资源丰富,西藏的羊八井和云南的腾冲地区是我国典型高温岩体地热资源区。文章分析了腾冲和羊八井高温岩体地热资源赋存的构造背景、地质结构、高温岩体类型、热源类型和现今构造应力状态等特征;比较了腾冲和羊八井高温岩体地热资源的异同;结合高温岩体开发中面临的工程技术问题,讨论了两个地区高温岩体地热资源开发的有利和不利条件;提出了羊八井地区是我国目前高温岩体地热资源开发的最有利地区的初步认识。     

地热异常区高温岩体圈定的思路与方法

高温岩体地热资源具有安全、清洁环保、不受季节和昼夜限制、资源量巨大等特点,开发利用高温岩体地热资源是解决未来能源问题的重要途径。高温岩体地热资源的开发利用首先要解决什么地方存在着目前技术和经济条件下可以开发利用的高温岩体地热资源。由于高温岩体是在特殊的地质构造条件下形成的特殊地质体,所以高温岩体圈定的本质是一个地质问题。高温岩体圈定的基本思路应该是在对高温异常区的岩石类型及分布、断裂构造格架及其活动性、火山活动和岩浆侵入的类型和时代等基础地质问题研究的基础上,并充分利用地球物理探测技术、遥感技术、地球化学方法,配合少量深钻验证工程。本文提出高温岩体地热资源圈定和评价的基本思路,并讨论了地质学方法、地球物理方法、遥感技术方法、地球化学方法等在高温岩体圈定中应用的有关问题,特别强调了多种方法和技术的相互配合、相互补充、相互验证。     

高温岩体圈定的思路与方法探讨

高温岩体地热资源开发利用首先要解决的是在目前技术和经济条件下可以开发利用的高温岩体分布地区和赋存深度及规模。提出了高温岩体圈定的基本思路应该是在对高温异常区的岩石类型及分布、断裂构造格架及其活动性、火山活动和岩浆侵入的类型及时代等基础地质研究的基础上,并充分利用地球物理探测技术、遥感技术、地球化学方法,配合少量深钻验证工程来进行。特别强调了在高温岩体地热资源圈定和评价中多种方法和技术的相互配合、相互补充、相互验证。     

高温岩体地热开发的技术经济评价

介绍了对美国Fenton Hill(芬登山)地区高温岩体地热开发所作的投资分析，以及应用MIT经济模型进行的高温岩体地热发电开发成本的预测与评价。研究认为，高温岩体地热资源从技术上来说是重要的潜在能源，但钻井技术和人工储留层的建造技术是阻碍其商业发展的关键因素；目前高地温梯度的高温岩体地热发电已具有商业竞争力，采用先进的线性钻井技术后，将使所有等级的地热梯度的高温岩体地热发电电价具有商业竞争能力。     

吉林省地热资源现状与评价研究

本文阐述了吉林省地热资源的类型、特点及地热资源的主要分布情况。以吉林省珲春、长白山、扶松3个主要地热异常区为例,阐述了地热资源的形成、地层特征,进而对吉林省地热开发效益进行初步评价     

漳州盆地等福建大陆裂谷地热资源与深部高温岩体地质响应研究

通过漳州盆地等福建省大陆裂谷地热资源与深部高温岩体地质响应的研究,表明大陆活裂谷是地下深部高温岩体活动与响应最剧烈的部位,往往成为地下热流汇聚的场所,成为地下热河,地表显示活裂谷轴部温泉串珠状排列,微小地震频繁,映衬地下干热岩地热资源丰富,具备狭义干热岩必要条件与充分条件,在此基础上提出干热岩地热资源综合开发利用建议。     

西藏高温地热国际研讨会召开

中国西藏高温地热国际研讨会于1992年8月9～16日在西藏拉萨召开。这次会议的目的是:(一)针对西藏高温地热资源进行论证,进一步研讨羊八井北部高温地热勘探开发的最佳程序和方法;(二)围绕深部高温地热资源开发和现有地热电站完善、优化管理以及地热资源综合梯级利用的关键问题进行学术交流;(三)为扩大高温地热资源的科学开发,广泛引进国内外先进技术,探讨引进资金的途径和方式,努力扩大对外经济科学技术合作。     

加快地热资源开发应重视的几个问题

l我国地热资源概况我国是一个地热资源丰富的国家,仅东部和西南部地区就有2500多处地热水出露点．在西藏的羊八井已探获329℃的高温地热资源,在台湾的北投已打出294℃的高温地热井。在云南的腾冲一梁河一带,其地热显示可与西藏羊八并相媲美,根据热海热田浅孔测温资料,地表20多m深处水温高达145℃。我国地热资源的地理分布恰好与当地的经济布局,大、中城市的规划区相匹配,有利于地热资源的因地制宜地大规模开发和利用。如在环渤海经济区,经过勘查已发现近百处地热田,其中京津保三角地区就有30多处地热田可供近期开发利用,地热资源…     

我国应大力推展地热能发电与供热（制冷）

地热能源来自地球深部,我国陆壳、地质环境带来广泛而丰富的高温岩体地热能和水热型地热能源。我国是世界上地热储量丰富的国家之一。虽然我国非电地热利用占世界第一,但是地热利用总量很小,特别是地热发电,高温岩体地热（热干岩）发电尚未起步。存在地热资源勘探程度低、地热低温发电技术滞后两个瓶颈。在我国《可再生能源法》引导下,增加地热能源内需投入、参与国际地热发电研究、地热供暖制冷）等开发利用,发展无碳地热经济,为我国建设小康社会和经济强国提供能源基础。大庆油田利用开发石油技术为地热能源的勘探、钻井、压裂、注水（回灌）、采水、地面工程、发电、供暖等提供技术支撑。最近省、市政府有关部门已批准“20万kW高温岩体地热分布式电站示范工程项目”前期工作,开展常规地热发电和高温岩体地热发电,同时供暖、供热水和地源热泵等地热梯级利用。     

地热资源的开发利用及可持续发展

地热资源作为一种新型能源矿产,具有分布广泛、易于开发等特点,其利用方式主要有地热发电和地热直接利用两种.我国具有良好的地热资源条件,主要为中低温地热资源.据计算,我国12个主要沉积盆地的地热可开采资源量为7500×1018J,相当于2560×108t标煤.当前,我国地热资源利用方式主要以供暖、洗浴、种植等直接利用为主;地热发电发展缓慢,主要分布在西藏;利用热泵技术开发地热资源得到了快速发展;油区地热资源的开发利用也取得了良好的经济和社会效益.但同时我国地热资源产业也面临着一些问题,包括大部分地区尚未开展地热资源勘查评价,影响了地热资源规划的制订及地热产业的发展;防腐、防垢技术还需要进一步加强研究;地热回灌率普遍过低;增强型地热系统研究有待加强等.为了促进地热资源的可持续发展,建议在加大地热资源勘查力度的同时,应以浅层地温能和热水型地热资源为主,发挥热泵技术的优势,开展地热资源的综合利用及梯级利用;重视和加快油气区地热资源的利用;在西藏等适宜地区加大高温地热能发电利用;集中全国优势技术力量,在一两个有利区域开展增强型地热系统技术探索;此外,走回灌开发道路是地热资源开发利用的必然选择.     

地热资源发电技术特点及发展方向

地热资源是一种清洁无污染、可再生的新型能源,对于发展低碳经济、实现可持续发展具有积极的作用.目前地热发电技术主要包括干蒸汽发电、扩容式蒸汽发电、双工质循环发电和卡琳娜循环发电等.其中干蒸汽发电系统工艺简单,技术成熟,安全可靠,循环效率可达20％以上,是高温地热田发电的主要形式;扩容式发电技术已在地热发电领域得到广泛应用,尤其是中高温地热田,二级扩容系统循环效率约为15％～20％;针对中低温地热资源,双工质循环发电技术是较为适用的,它由地热水系统和低沸点介质系统组成,循环效率较扩容式蒸汽发电技术可提高20％～30％;卡琳娜循环在低温地热资源应用领域中有其独特的优越性,通过调整氨和水的比例,可以适应低温地热水的发电特性,卡琳娜循环发电技术的循环效率比朗肯循环的效率高20％～50％.在低温地热资源的开发利用过程中,双工质循环和卡琳娜循环技术具有广阔的发展前景.作为一种新型地热资源,干热岩具有很高的开发利用价值.新型的联合循环发电技术是地热发电技术的发展方向.在浅层地热能得到大规模开发后,中深层地热资源和干热岩资源将成为地热发电技术新的资源,我国应注重中深层地热资源和干热岩资源的开发.     

An overview of the state of geothermal energy

This paper provides an overview of the present status of geothermal energy world-wide. Although the origin of this form of energy dates back in history, its impetus (with the notable exceptions of Italy and Iceland) was the ‘energy crisis’ of the mid to late 1970s. A wide range of speculations were made during those years as to the potential contribution of geothermal energy to the world energy demand. The present lull in the energy scene allows a more realistic assessment of present and near future potential. Problem areas related to the development of the geothermal resource potential are also discussed. They address both natural, mainly liquid dominated, sources and the recovery of heat stored at depth in impervious rocks through man-made geothermal reservoirs known as the hot dry rock concept of heat mining.     

Geothermal energy technology and current status: an overview

Geothermal energy is the energy contained as heat in the Earth’s interior. This overview describes the internal structure of the Earth together with the heat transfer mechanisms inside mantle and crust. It also shows the location of geothermal fields on specific areas of the Earth. The Earth’s heat flow and geothermal gradient are defined, as well as the types of geothermal fields, the geologic environment of geothermal energy, and the methods of exploration for geothermal resources including drilling and resource assessment.Geothermal energy, as natural steam and hot water, has been exploited for decades to generate electricity, and both in space heating and industrial processes. The geothermal electrical installed capacity in the world is 7974 MW_e (year 2000), and the electrical energy generated is 49.3 billion kWh/year, representing 0.3 % of the world total electrical energy which was 15,342 billion kWh in 2000. In developing countries, where total installed electrical power is still low, geothermal energy can play a significant role: in the Philippines 21% of electricity comes from geothermal steam, 20% in El Salvador, 17% in Nicaragua, 10% in Costa Rica and 8% in Kenya. Electricity is produced with an efficiency of 10–17%. The geothermal kWh is generally cost-competitive with conventional sources of energy, in the range 2–10 UScents/kWh, and the geothermal electrical capacity installed in the world (1998) was 1/5 of that from biomass, but comparable with that from wind sources.The thermal capacity in non-electrical uses (greenhouses, aquaculture, district heating, industrial processes) is 15,14 MW_t (year 2000). Financial investments in geothermal electrical and non-electrical uses world-wide in the period 1973–1992 were estimated at about US$22,000 million. Present technology makes it possible to control the environmental impact of geothermal exploitation, and an effective and easily implemented policy to encourage geothermal energy development, and the abatement of carbon dioxide emissions would take advantage from the imposition of a carbon tax. The future use of geothermal energy from advanced technologies such as the exploitation of hot dry rock/hot wet rock systems, magma bodies and geopressured reservoirs, is briefly discussed. While the viability of hot dry rock technology has been proven, research and development are still necessary for the other two sources. A brief discussion on training of specialists, geothermal literature, on-line information, and geothermal associations concludes the review.     

A comparative thermodynamic analysis of Kalina and organic Rankine cycles for hot dry rock: a prospect study in the Gonghe Basin

Hot dry rock is a new type of geothermal resource which has a promising application prospect in China. This paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe Basin. Based on the given heat production conditions, a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine eco-friendly working fluids. The results show that the optimal ammonia mass fraction is 82% for the proposed bottoming Kalina cycle in view of maximum net power output. Thermodynamic analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine, respectively. The maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations, and is far higher than the maximum net power output in all tested Kalina cycle cases. Under the given heat production conditions of hot dry rock resource in the Gonghe Basin, the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.     

Hot dry rock: a new geothermal energy source

A project being conducted by the Los Alamos Scientific Laboratory is attempting to demonstrate the technical and economic feasibility of extracting energy from the hot, dry rock geothermal resource. The system being tested is composed of two deep boreholes drilled into hot, impermeable rock and connected by a hydraulically produced fracture. In September 1977, the circulation loop was closed for the first time and water was circulated through the downhole reservoir and through a pair of 10-MW (thermal) heat exchangers. A series of long-term experiments is planned for 1978 in order to evaluate the thermal, chemical and mechanical properties of the energy extraction system.     

U型井开发干热岩井筒温度场研究

目前干热岩开发主要采用水力压裂的方式,而以U型井方法取代固有开发模式,具有减少水损、提高能量衰减周期,避免诱发地震等显著优势。因此,建立了U型井井筒和干热岩储层非稳态流动传热耦合模型,采用有限体积法结合Crank-Nicolson全隐式格式进行离散求解,并通过地热井数据验证了模型的可靠性。研究了干热岩开采过程中井筒及地层的温度变化特征,定量分析不同的敏感性因素对出口温度的影响,利用正交试验法明确影响取热量大小的因素排列。结果表明：各个因素的大小对出口温度影响明显,而影响取热量的因素由主到次排序为：注入流量、水损率、岩石导热系数、水平段长度、入口温度、井筒直径。研究成果进一步完善了干热岩高效热提取理论,可为我国干热岩地热能的开发利用提供借鉴作用。     

中国地热能源开发的机遇与挑战

作为低碳新能源家族的一员,地热能源开发已经被提到国家应对气候变化和防治雾霾的议事日程.本文回顾了地热资源开发历史,分析了我国地热能源开发落后的原因,认为要切实改变当前的落后局面,不仅需要产业界克服工程技术方面的障碍,而且需要地热学界重新评估我国包括水热系统和干热岩在内的地热资源分布格局,更需要政府主管部门调整目前偏重西部边远地区而轻视能源需求旺盛的东部地区的地热能源开发指导方针.     

Forecast and evaluation of hot dry rock geothermal resource in China

Utilizing information from plate tectonics characteristics, volcanic activities, and geothermal anomaly, this paper identifies areas where hot dry rock (HDR) may exist as potential geothermal resource in China. Further investigations are also carried out in the paper based on results from regional tectonics, volcanic geology and lithology, as well as data from geothermal displays, geochemistry, geophysics, and shallow borehole temperature measurements. The study reveals several promising areas of HDR geothermal resource in China, including Tengchong of Yunnan province, Qiongbei of Hainan province, Changbaishan of Jilin province, Wudalianchi of Heilongjiang province, and the Southern Tibet area. A 3D static heat conduction model was developed to study the underground temperature gradient characteristics of the Rehai geothermal field in Tengchong and the Yangbajing geothermal field in Tibet. The model adopted is a geological block 10 km deep from the ground surface and 50 km wide in each of the horizontal directions (2500 km² area). The numerical simulation results in evaluations on the quantities of the HDR geothermal resource in Rehai and Yangbajing geothermal fields. The paper shows that there is abundant HDR geothermal resource with large exploitation value in China. If developed with a power capacity of 1×10⁸ kW, the Rehai and Yangbajing fields along would be able to generate electricity for 1560 years.     

深井CO2爆破致裂干热岩系统综合效应预评价

CO₂爆破致裂工艺为建造商业化EGS储层提供了新方案,有望突破深层地热能行业发展的技术瓶颈,但目前未见CO₂致裂技术用于干热岩系统的综合性能评价研究。基于此研究不足,借助数学建模定量科学评价其综合性能,解决此技术效果的不确定性和模糊性,填补深井地热系统综合评价体系的空白。考虑到深井CO₂爆破干热岩系统是一个多变、模糊、复杂的非线性系统,该文选取AHP-FCE优化数学模型,AHP对深井爆破干热岩系统复杂问题分层,构建递阶层次结构,通过Matlab将专家的定性判断定量化,进而确定FCE中各层评价指标权重大小,再通过FCE模糊关系合成原理,对多因素影响下的深井CO₂爆破致裂干热岩系统综合评分为83.36,预评价结果为较好,可考虑将CO₂爆破致裂器用于干热岩开采。评定结果可作为深井CO₂爆破致裂干热岩建设过程中的数据支撑,为地热开采工程提供一定的理论依据。     

Development program of hot dry rock geothermal resource in the Yangbajing Basin of China

Geothermal energy from hot dry rock (HDR), considered an almost inexhaustible source of “green” energy, was first developed and tested in the 1970s, leading to installations in America, Japan, Britain, France and other countries. In the present work, a liquating rock mass at a depth of 5-15 km in the Tibet Yangbajing region in China was subjected to detailed analysis. The temperature distribution of the geothermal field in the region was determined by the finite element method. The results estimate that the HDR geothermal resource of the Yangbajing region is 5.4 × 10⁹ MW a, representing a huge potential source of HDR geothermal energy for China. Based on detailed research into the continental dynamics of the environment forming the HDR geothermal field of Tibet, along with the tectonic characteristics of the southern slope of Tanggula Mountain and the Dangxiong-Yangbajing Basin, and the magnitude and orientation of the in situ stresses in the region, the design of an arrangement for extracting these HDR geothermal resources is proposed: taking the fault zone nearest the high-temperature liquating rock region as the location of an artificial reservoir, a vertical injection well could be drilled at a low point on the downdip side of the fault, and two dipping production wells drilled higher up. In this way, an artificial reservoir 3 × 10¹¹ m³ in volume would be created: 360 times the volume of the HDR geothermal reservoir in Cornwall, UK, which uses hydrofracturing. An investigation of the reservoir features, including seepage analysis of the heat exchange area, project implementation and investment analysis, indicates that a 10⁴ MW capacity power station with a projected operating life of approximately 100 years could be constructed. An analysis of a geothermal extraction system comprising one injection well and two production wells suggest that a power station of 1000 MW installed capacity could be constructed initially to provide electricity production of 8.64 × 10⁹ kWh per year.