采暖用增强型地热系统动态特性研究

发布时间：2018-02-21 07:32

本文关键词： 采暖增强型地热系统动态特性　出处：《中原工学院》2017年硕士论文　论文类型：学位论文

【摘要】：自21世纪以来,我国经济快速增长,科研、技术等方面都取得翻天覆地的变化。但严重的生态环境污染已经对我国经济的快速、健康发展产生严重制约,因此发展新型能源成为焦点。地热能与其他新型能源相比,除具有环保等共同特点外,还更加稳定安全,可以被运用在供暖行业。我国寒冷地区常用的供暖方法包括热电联产、锅炉房供暖以及新型地源热泵系统三种。但这些系统或多或少均会对环境造成一定的危害,所以研究新型地热采暖方式成为一种发展的趋势。本文中所研究的采暖用增强型地热系统,是新型采暖方式的一种,其热源是地下几千米深的高温岩石——干热岩,整个换热过程中仅存在着能量的交换,能够避免更多的环境问题。文章针对一对一(即一个注水井,一个生产井)干热岩开采物理模型,建立了系统的动态模型,利用Gambit软件和Fluent软件对地下热储层在供暖周期内的动态进行了数值模拟分析。模拟研究了85℃、100℃、115℃、130℃、145℃五种不同岩层温度,2cm、1.6cm、1.4cm、1cm、0.8cm五种不同裂隙宽度,以及1cm/s、0.9cm/s、0.8cm/s、0.7cm/s和0.6cm/s五种不同水流速对增强型地热系统动态特性的影响规律。通过分析五种不同岩层温度、裂缝宽度以及水流速下的出水温度、岩层温度分布、监测面流体温度的变化规律以及岩层的供热能力,确定了干热岩开发时岩层初始温度、裂缝宽度以及水流速的基本原则,为制定干热岩系统开发方案奠定了基础。通过对模拟结果的分析,可以知道:岩石初始温度越高,裂缝之间的干扰距离越大,开发方案中确定裂缝间距时可以选择较大的距离;在裂隙宽度为2cm,水流速为1cm/s的情况下,岩石初始温度为115℃时,裂隙间距应为9.5m,初始温度为145℃时,裂隙间距为10.2m。储层内裂隙宽度越小,岩层等温线斜率越高,岩层内温度分布越不均匀,低温区域越为集中,越不利于储层在非采暖期内热量的恢复,影响系统的使用年限,但生产井水温降低时间延迟,且降低速度慢,两井间最短距离减小,有利于节约投资成本,降低压裂难度;在岩层初始温度为115℃,流速为1cm/s的情况下,裂隙宽度为2cm时,生产井温度降低时间为150h,两井间最短距离应达到500m;裂隙宽度为1cm时,生产井温度降低时间为600h,两井间最短距离应达到250m。裂隙水流速度越大,岩层内等温线斜率越低,岩层温度分布越均匀,越有利于储层在非采暖期内热量的恢复,但生产井水温降低时间早,且降低速度快,两井间最短距离增大,投资成本及技术难度增加;在岩层初始温度为115℃,裂隙宽度为1.4cm的情况下,水流速为1cm/s时,生产井水温降低时间为300h,两井间最短距应达到350m;水流速度为0.8cm/s时,生产井水温降低时间为600h,两井间最短距应达到300m。对供热能力而言,在人工热储体积相同的情况下,水流速度越慢、裂隙宽度越小时,虽然生产井出水温度越高,但满足的供热面积越小;岩石初始温度为115℃,裂隙宽度为1.4cm,热储层体积为0.045km3时,1cm/s和0.6cm/s的流速下,生产井出水温度分别为:87℃、103℃,其供暖面积分别为:100万平方米、88万平方米。
[Abstract]:Since twenty-first Century, China's rapid economic growth, scientific research, have made changes in turn the world upside down technology. But the serious ecological environment pollution has on our economy fast, seriously restricting the healthy development, so the development of new energy has become the focus of geothermal energy. Compared with other new energy, environmental protection has the common characteristics. It is more stable and safe, can be used in the heating industry. China's cold area heating method includes cogeneration boiler room heating and new ground source heat pump system three. But these systems are more or less will cause certain harm to the environment, so the study of new heating geothermal has become a development trend of enhanced geothermal. System for heating in this paper, a new type of heating mode, the heat is several thousand meters deep underground hot rock, hot dry rock, the whole heat transfer process Only the existence of energy exchange, to avoid environmental problems. Aiming at the more one on one (that is a water injection wells, a production wells) hot dry rock mining model, the dynamic model of this system, the underground heat reservoir in the heating period of dynamic numerical simulation analysis was carried out using Gambit software and the Fluent software. The simulation of 85 C, 100 C, 115 C, 130 C, 145 C five different strata temperature, 2cm, 1.6cm, 1.4cm, 1cm, 0.8cm five different crack width, and 1cm/s, 0.9cm/s, 0.8cm/s, 0.7cm/s and 0.6cm/s five different water flow rate on the influence of enhanced dynamic characteristics geothermal system. Through the analysis of the five different temperature layers, water temperature and water flow rate of the crack width, rock temperature distribution, variation of surface temperature and monitoring fluid rock heating capacity, the development of hot dry rock strata to determine the initial temperature, crack width The basic principle and flow velocity, which laid the foundation for the development of hot dry rock system. Through the analysis of simulation results, we can know that the initial rock temperature is higher, the greater the interference distance between cracks, determine the crack spacing in the development program can choose a larger distance; in the crack width of 2cm, water flow rate for the case of 1cm/s, the initial temperature of rock is 115 degrees centigrade, fracture spacing should be 9.5m, the initial temperature is 145 degrees centigrade, fracture spacing of 10.2m. reservoir in the crack width is smaller, the higher the isotherm slope rock, rock temperature distribution is uneven, low temperature region is concentrated, is not conducive to reservoir in the non heating period of heat recovery, affect the service life, but the production of water temperature to reduce the time delay, and reduce the speed, the shortest distance between two wells decreases, can save the investment cost, reducing the pressure on the initial temperature of rock crack difficulty; 115 degrees C, flow rate is 1cm/s, the width of the crack is 2cm, producing wells temperature decrease time was 150h, the shortest distance between two wells should reach 500m; the fracture width is 1cm, the production wells temperature decrease time was 600H, the shortest distance between two wells should reach 250m. fissure water flow velocity is in the lower strata in the isotherm slope, rock temperature distribution is more uniform, more conducive to the reservoir in the non heating period of heat recovery, but the production of water temperature decreased early in time, and reduce the speed, the shortest distance between two wells increases, the cost of investment and technical difficulty; the initial temperature is 115 DEG C in rock and the fracture width is 1.4cm, the flow rate is 1cm/s, production wells water temperature reduction time is 300h, the distance between two wells should reach 350m; the flow rate is 0.8cm/s, production wells water temperature reduction time is 600H, the distance between two wells should reach 300m. of heating capacity, in person Heat storage under the condition of the same volume, the flow rate is slower, the width of the crack is smaller, although the production wells and water temperature is high, but to meet the heating area is smaller; the initial temperature of rock is 115 DEG C, crack width is 1.4cm, the heat reservoir volume is 0.045km3, 1cm/s and 0.6cm/s flow rate, temperature wells water production were: 87 degrees, 103 degrees, the heating area was 1 million square meters, 880 thousand square meters.

【学位授予单位】：中原工学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU832

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