油区地热能综合利用方案分析——以福山油田为例*

油田区域地热资源十分丰富,并且存在大量的用热需求。在油田地区综合开发地热能,不仅可以解决油田伴热、社区供暖/制冷等问题,还可以降低环境污染,减少二氧化碳的排放,有利于油田的持续稳定发展。基于海南福山油田的地热资源条件及用能需求,将油田生产伴热、热泵尾水升温和地热驱动吸收式制冷技术相结合,设计了多种油田地热能综合利用方案,并计算比较了各个方案的经济收益,进一步分析了地热水温度和流量对各个方案适用性的影响,研究结果可为其他油田区域地热资源的综合开发利用提供参考。     

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.     

Use and potential of geothermal energy in Belgium

Our basic knowledge of the geothermal potential in Belgium derives from existing geological reconnaissance surveys. As a result of the energy arises in the 1970s and early 1980s, efforts were made by public organisations such as the Belgian National Geological Survey and the Directorate-General for Science, Research and Development of the European Community to acquire further fundamental knowledge in the geological and technological fields related to the implementation of low-enthalpy geothermal projects. This led to the development of a low-enthalpy geothermal plant close to Mons in the south, and to a demonstration project for a doublet system in north Belgium. Following the drop in oil prices in the mid-eighties, there was a corresponding decrease in the efforts to develop geothermal installations. The resources of the potential areas identified in a previous work were assessed. This paper updates the resource assessment to the end of 1994 and describes the current, albeit limited, use of geothermal energy in Belgium.     

Characteristics of low-enthalpy geothermal applications in Greece

The paper offers a brief overview of the current direct geothermal uses in Greece and discusses their characteristics, with emphasis to the economical and technical problems encountered. Greece holds a prominent place in Europe regarding the existence of promising geothermal resources (both high and low-enthalpy), which can be economically exploited. Currently, no geothermal electricity is produced in Greece. The installed capacity of direct uses at the end of 2009 is estimated at about 155 MW_t, exhibiting an increase of more than 100% compared to the figures reported at the World Geothermal Congress 2005. The main uses, in decreasing share, are geothermal heat pumps, swimming and balneology, greenhouse heating and soil warming. Earth-coupled and groundwater (or seawater) heat pumps have shown a drastic expansion during the past 2–3 years, mainly due to high oil prices two years ago and easing of the license requirements for drilling shallow wells.     

Optimization of downhole pump setting depths in liquid-dominated geothermal systems: A case study on the Balcova-Narlidere field,Turkey

Downhole pumps are being used increasingly more often in low-enthalpy geothermal wells. The depth at which these pumps are installed depends on the physical and chemical characteristics of the geothermal fluid, the production flow rate, and the reservoir pressure and permeability. In this study we have investigated the factors affecting pump setting depths in low-temperature, liquid-dominated geothermal systems and defined the relationship between flow rate and pressure drawdown based on multi-rate test results. The methodology proposed was applied to the Balcova-Narlidere geothermal field, Turkey. It was found that the most important parameters for determining the capacity and setting depth of a downhole pump were flow performance, non-condensable gas concentration, and temperature. The implementation of the methodology is illustrated.     

Sustainability aspects of geothermal heat pump operation, with experience from Switzerland

Geothermal heat pumps are the key to the utilization of the ubiquitous shallow geothermal resources. Theoretical and experimental studies, performed in Switzerland over several years, have established a solid scientific base of reliable long-term operation of borehole heat exchanger-coupled heat pump systems. Proper design, taking into account local conditions like ground properties and building needs, ensures the sustainability of production from systems with single and multiple borehole heat exchangers. Long-term experience acquired at operational objects confirms the predictions.     

Classification of Geothermal Energy Resources in Japan Applying Exergy Concept

Higher demand for energy consumption and importance of environmental issues has encouraged researchers and policy makers to consider renewable energies more seriously. Geothermal resources are a green energy source that can make a considerable contribution in some countries. Japan has the third ranking geothermal energy potential, and its geothermal electricity production is currently eighth in the world. Since the nature of geothermal resources dictates its method of utilization, it is important to categorize available resources. There is no consensus on classification of geothermal resources. Most scientists, from geologist to engineers, agree on the term temperature. However, temperature or enthalpy alone cannot describe the nature of fluids; they can have same temperature with different phases, such as saturated water or saturated steam. Using exergy for resource classification benefits their comparison, according to their ability to do work. In this paper, exergetic classification of geothermal resources was applied to 18 under‐operating geothermal power plants in Japan. Six geothermal fields have high exergy resources according to their SExI values in excess of 0.5. The remaining geothermal fields in Japan are classified in the medium resources zone. Classification results can be used by decision makers as a reference for future geothermal development. Copyright © 2012 John Wiley & Sons, Ltd.     

Study of different grouting materials used in vertical geothermal closed-loop heat exchangers

As a renewable source, low-enthalpy geothermal energy is becoming more relevant in heating and cooling buildings, by using an adapted heat pump to exchange thermal energy with the ground. Vertical closed-loop geothermal systems exchange heat with the ground through a closed buried pipe system, sealed with a grouting material that ensures the stability and thermal transmission of the borehole. Different grouting materials have been tested recently, which use cement or bentonite as a base material. However, the use of recycled materials, which might contribute to the sustainability of the project, has not yet been studied. This paper analyzes the use of different natural and recycled aggregates as main constituents in cement-based mortars. Results show that all mixes fulfill the minimum consistency and strength requirements. The use of any of the aggregates proposed improves the thermal conductivity compared to the cement mortar on its own, independently of the proportion used. Limestone sand, silica sand and electric arc furnace slag enhance the thermal conductivity of the grout as its proportion of use increases. However, no satisfactory results have been obtained for Construction and Demolition Waste-based mixes because of their high water requirement.     

Geothermal resources in Algeria

The geothermal resources in Algeria are of low-enthalpy type. Most of these geothermal resources are located in the northeastern of the country. There are more than 240 thermal springs in Algeria. Three geothermal zones have been delineated according to some geological and thermal considerations: (1) The Tlemcenian dolomites in the northwestern part of Algeria, (2) carbonate formations in the northeastern part of Algeria and (3) the sandstone Albian reservoir in the Sahara (south of Algeria). The northeastern part of Algeria is geothermally very interesting. Two conceptual geothermal models are presented, concerning the northern and southern part of Algeria. Application of gas geothermometry to northeastern Algerian gases suggests that the reservoir temperature is around 198 °C. The quartz geothermometer when applied to thermal springs gave reservoir temperature estimates of about 120 °C. The thermal waters are currently used in balneology and in a few experimental direct uses (greenhouses and space heating). The total heat discharge from the main springs and existing wells is approximately 642 MW. The total installed capacity from producing wells and thermal springs is around 900 MW.     

Comparison of U.K. geothermal and U.S. oil well costs

As part of the development of a complete cost model for low-enthalpy geothermal energy systems, a detailed investigation was carried out on the major cost components involved in drilling wells in sedimentary regions. A drilling cost model, WDCM, was produced as a result of this work. This paper reports the use of the model in explaining differences in the cost of U.S. oil and gas wells and U.K. low-enthalpy geothermal wells, in particular. A comparison with the cost of French low-enthalpy geothermal wells is included.     

Direct utilization of geothermal energy 2010 worldwide review

This paper presents a review of the worldwide application of geothermal energy for direct utilization, and updates the previous survey carried out in 2005. We also compare data from 1995 and 2000 presented at World Geothermal Congresses in Italy and Japan, respectively (WGC95 and WGC2000). As in previous reports, an effort is made to quantify ground-source (geothermal) heat pump data. The present report is based on country update papers prepared for WGC2010 and other sources of data available to the authors. Final update papers were received from 70 countries of which 66 reported some direct utilization of geothermal energy. Twelve additional countries were added to the list based on other sources of information. Direct utilization of geothermal energy in 78 countries is a significant increase from the 72 reported in 2005, the 58 reported in 2000, and the 28 reported in 1995. An estimate of the installed thermal power for direct utilization at the end of 2009 is used in this paper and equals 48,493 MWt, almost a 72% increase over the 2005 data, growing at a compound rate of 11.4% annually with a capacity factor of 0.28. The thermal energy used is 423,830 TJ/year (117,740 GWh/yr), about a 55% increase over 2005, growing at a compound rate of 9.2% annually. The distribution of thermal energy used by category is approximately 47.2% for ground-source heat pumps, 25.8% for bathing and swimming (including balneology), 14.9% for space heating (of which 85% is for district heating), 5.5% for greenhouses and open ground heating, 2.8% for industrial process heating, 2.7% for aquaculture pond and raceway heating, 0.4% for agricultural drying, 0.5% for snow melting and cooling, and 0.2% for other uses. Energy savings amounted to 250 million barrels (38 million tonnes) of equivalent oil annually, preventing 33 million tonnes of carbon and 107 million tonnes of CO₂ being release to the atmosphere, this includes savings for geothermal heat pumps in the cooling mode (compared to using fuel oil to generate electricity).     

太原市亲贤地垒区地下热水成因及地热资源评价

为了科学合理开发利用地热资源,在分析太原市亲贤地垒区地热田形成背景的基础上建立了地热田地质模型,分析了热水补给来源和运移机制,并对地热资源进行了评价。结果表明,太原市亲贤地热田地热水来源于大气降水补给,属滞流型无氚老水;亲贤地垒区热田具备了良好的盖层、热储、热源和水循环通道等地质条件,热水是经深循环(受深部热源加热)而形成的;热水开采量不能超过3 600m3/d,热水储存资源量为9.76×108 m3,可实现开采的地热能折合标准煤约1 500×104t。     

国外能源公司地热能利用现状以及对中国石化的启示

地热能作为一种无污染、可再生的清洁能源,具有稳定可靠、成本低廉、清洁环保等优点。国外能源公司在地热能利用方面积累了成功的技术和管理经验．其中以冰岛绿源公司为代表的地热供暖、以雪佛龙为代表的地热发电、以壳牌为代表的干热岩发电处于国际领先地位。这些公司都拥有雄厚的资金实力、良好的国际声誉以及完整的产业链;并且都集中优势资源,重点发展某一项地热业务．而后再逐渐向地热能利用的其他领域扩张;同时还具备完善的科研设备和一流的科研人员,注重科技创新。中国石化正在积极扩大地热能研究和利用工作,旗下新星石油公司已发展成为国内常规地热能开发利用的第一大公司。截至2012年底,新星石油公司地热供暖能力达1000×10^4m2,约占全国常规地热供暖面积的25％。今后中国石化应逐步拓展地热能利用范围。延伸地热能利用产业链;加强科研攻关,积极创新,促进地热开发利用关键技术研发及推广应用;同时要加强国际交流与合作,加快地热开发利用技术的制度建设,并积极争取国家、地方的优惠政策和支持,推动我国地热产业快速健康发展。     

Low-enthalpy geothermal energy: An opportunity to meet increasing energy needs and reduce CO2 and atmospheric pollutant emissions in Piemonte,Italy

The scope for diffusion of very low-enthalpy geothermal plants in the Piemonte region of Italy, using groundwater heat pumps (GWHP), was analyzed to check environmental sustainability and the benefits in terms of reducing greenhouse gas emissions from fossil fuels. GWHP implementation seemed particularly suitable to the specific characteristics of the Piemonte plain. An important thick and productive shallow aquifer is present across the entire plain beneath the major energy users and is therefore appropriate for geothermal energy development purposes. The building stock could be adapted to heat pumps in different ways, but objective-oriented policies will be required to reach the best results in terms of environmental benefits.     

青岛蓝色硅谷土壤热物性测试与分析

青岛蓝色硅谷区域地质构造特殊,地热资源丰富。目前该区域地热资源的勘查程度较低,地热资源利用形式单一,优质地热资源浪费严重。本文采用岩土热响应测试法对蓝色硅谷区域内的地埋管测试孔的岩土热物性进行了现场测试,利用48 h的测试数据,采用线热源模型进行数据分析,得到土壤导热系数为2.278 W/(m∙K)。同时,采用柱热源模型模拟夏季工况,得到的流体温度变化趋势与实验工况相同,且进、出水温度分别为35.1℃和30.4℃,与实验工况下的35.1℃及30.8℃吻合较好。该研究可用于指导土壤源热泵的热物性分析以及青岛蓝色硅谷地热资源综合开发。     

Coupling of geothermal heat pumps with thermal solar collectors

The study discussed relates to the design and development of a process consisting of combining a reversible geothermal heat pump with thermal solar collectors for building heating and cooling and the production of domestic hot water. The proposed process, called GEOSOL, has been installed in a 180 m² private residence in 2004. This installation is the subject of long-term experimental follow-up to analyse the energy-related behavior of the installation at all times of the year. In addition, different configurations of this combined system (geothermal heat pump and thermal solar collectors) have been defined and will be simulated numerically using TRNSYS software. A comparative analysis of these different alternative versions will be conducted to determine the best configuration(s) of the GEOSOL process in terms of energy, economical and environmental performances.     

散热器与水源热泵串联运行利用低温地热水供暖的方法研究

提出了低温地热水先经过散热设备散热后再进入热泵的地热水梯级利用的方法,并建立了两种方法的分析模型。结合工程实例对二者进行的分析表明混水方法的效率为8.9%,地热梯级利用方法的效率为15.9%。还用寿命周期费用法对地板辐射盘管与热泵串联的经济性匹配进行了分析。     

The potential of district heating using geothermal energy. A case study, Greece

The purpose of this study is to investigate the possibility of using low-enthalpy geothermal energy from the geothermal field of Sousaki in the province of Korinthos, Greece, to cover the thermal needs of the nearby town of Ag. Theodori. The possibility of developing a system of district heating was examined based on a proposed town model. Total thermal demands were calculated on the basis of a model dwelling and prevailing weather conditions in the area. Subsequently, a heat transfer circuit is proposed, including the distribution network, the heat exchanger, the production and reinjection pumps, and the pumping station. Finally, energy indices are presented, such as demand in tons of equivalent oil and CO₂ emissions.     

热泵技术与可再生能源的开发利用

目前,可再生能源和热泵技术受到广泛的重视.通过对可再生能源与热泵关系的分析以及对热泵低温热能采集方式的论述表明,可再生能源是热泵低温热源的主要来源,而热泵是可再生能源低温热利用最有效的方式,热泵技术的利用极大地拓展了可再生能源的利用范围.     

Geothermal development in Romania

Exploration for geothermal resources began in Romania in the early 1960s, based on a detailed geological exploration program for hydrocarbon resources that had a capacious budget and enabled the identification of eight geothermal areas. Over 200 wells drilled to depths between 800 and 3500 m have indicated the presence of low-enthalpy geothermal resources (40–120 °C). Completion and experimental production from over 100 wells during the past 25 years has led to the evaluation of the exploitable heat resources of the geothermal reservoirs. The proven reserves, with the wells that have already been drilled, amount to about 200,000 TJ for 20 years. The main geothermal systems discovered on Romanian territory are in porous permeable formations such as sandstones and siltstones (Western Plain and the Olt Valley) or in fractured carbonate formations (Oradea, Bors, and north of Bucharest). The total thermal capacity of the existing wells is about 480 MW_t (for a reference temperature of 25 °C). Only 152 MW_t of this potential is currently being exploited, from 96 wells (35 of which are used for health and recreational bathing), producing hot water in the temperature range 45–115 °C. In 2002 the annual energy utilisation from these wells was about 2900 TJ, with a capacity factor of 0.6. More than 80% of the wells are artesian producers, 18 wells require anti-scaling chemical treatment and six are reinjection wells. During the period 1995–2002, 15 exploration-production geothermal wells were drilled and completed, two of which were dry holes. Drilling was financed by the geological exploration fund of the State Budget, to depths varying between 1500 and 3500 m. Progress in the direct utilisation sector of geothermal resources has been extremely slow because of the difficulties encountered during the transition period from a centrally planned to a free-market economy; geothermal production is at present far below the level that could be expected from its assessed potential, with geothermal operations lagging behind in technology. The main obstacle to geothermal development in Romania is the lack of domestic investment capital. In order to stimulate the interest of potential investors from developed countries and to comply with the requirements of the large international banks, an adequate legal and institutional framework has been created, adapted to a market-oriented economy.