共查询到20条相似文献,搜索用时 93 毫秒
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对一个与生产井结合的集总参数热储模型,评估了地热流体生产量的变化。据研究结果得出结论:①在生产开始后不久,直到热储到饱和状态,流量急剧下降;②之后,保持一段时间稳定,在无回灌情况下突然下降。尽管回灌低温水,但流量仍然逐渐减少;③如果来自热源的流体流入量大到足以使热储保持非饱和状态,则流量可长时间(超过1×10^5h)保持稳定。 相似文献
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在浅层地热能利用中,获取准确的岩土体热物性参数对地源热泵系统优化设计非常重要,但因原位测试常常受到地下水渗流的影响,导致所得参数不准确,从而使系统的设计浪费或失效。为此,设计了一套渗流控制系统,结合线热源测试原理,测试了长江一级阶地汉口地区的两种饱和砂土样在不同渗流速率下的热物性参数,并引入贝克来数评价了渗流作用对砂土传热性能的影响。结果表明,渗流对饱和砂土的热传导特性测试结果有明显的影响,且影响程度随渗流速率的增加而增强,对德国纽伦堡市一处地源热泵系统的测试亦验证了渗流对导热系数测试结果的增强作用。 相似文献
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The fracture characteristics of a heat reservoir are of critical importance to enhanced geothermal systems, which can be investigated by theoretical modeling. This paper presents the development of a novel flow-resistor network model to describe the hydraulic processes in heat reservoirs. The fractures in the reservoir are simplified by using flow resistors and the typically complicated fracture network of the heat reservoir is converted into a flow-resistor network with a reasonably simple pattern. For heat reservoirs with various fracture configurations, the corresponding flow-resistor networks are identical in terms of framework though the networks may have different section numbers and the flow resistors may have different values. In this paper, numerous cases of different section numbers and resistor values are calculated and the results indicate that the total number of flow resistances between the injection and production wells is primarily determined by the number of fractures in the reservoir. It is also observed that a linear dependence of the total flow resistance on the number of fractures and the relation is obtained by the best fit of the calculation results. Besides, it performs a case study dealing with the Soultz enhanced geothermal system (EGS). In addition, the fracture numbers underneath specific well systems are derived. The results provide insight on the tortuosity of the flow path between different wells. 相似文献
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A large amount of fluid circulation and heat extraction (i.e., thermal power production) research and testing has been conducted on engineered geothermal reservoirs in the past 15 years. In confined reservoirs, which best represent the original Hot Dry Rock concept, the flow distribution at any given time is primarily determined by three parameters: (1) the nature of the interconnected network of pressure-stimulated joints and open fractures within the flow-accessible reservoir region, (2) the mean pressure in the reservoir, and (3) the cumulative amount of fluid circulation—and therefore reservoir cooling—that has occurred. For an initial reservoir rock temperature distribution and mean fluid outlet temperature, the rate of heat extraction (i.e., thermal power) is at first only a function of the production flow rate, since the production temperature can be expected to remain essentially constant for some time (months, or even years). However, as reservoir circulation proceeds, the production temperature will eventually start to decline, as determined by the mean effective joint spacing and the total flow-accessible (i.e., heat-transfer) volume of the reservoir. The rate of heat extraction, which depends on the production flow rate, can also vary with time as a result of continuing changes in the flow distribution arising from reservoir cooling.The thermal power of engineered reservoirs can most readily be increased by increasing the production flow rate, as long as this does not lead to premature cooldown, the development of short-circuit flow paths, or excessive water losses. Generally, an increase in flow rate can be accomplished by increasing the injection pressure within limits. This strategy increases the driving pressure drop across the reservoir and the mean reservoir pressure, which in turn reduces the reservoir flow impedance by increasing the amount of joint dilation. However, the usefulness of this strategy is limited to reservoir operating pressures below the fracture extension pressure, and may lead to excessive water losses, particularly in less-confined reservoirs. Under such conditions, a downhole production-well pump may be employed to increase productivity by recovering more of the injected fluid at lower mean reservoir operating pressures. 相似文献
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Radon has been shown to have potential as a tracer in the study of geothermal reservoirs. The combination of its physical and nuclear properties and its emanation and transport in geothermal fluids makes several types of time and concentration measurements useful for studies of fracture permeability and porosity and flow characteristics in different types of geothermal resources. Radon concentrations in several vapor-dominated and liquid-dominated producing reservoirs have been measured by short-period sampling of wellhead geofluid followed by radon separation on a charcoal trap and counting in a sensitive low background ZnS detector. The results show significant variations not only among different fields, but also between neighbouring wells in a single field. Evidences for transport differences between the two major types of hydrothermal systems are noted. 相似文献