干热岩地热资源开采井网优化数值模拟研究

发布时间：2018-06-23 17:01

本文选题：干热岩开发 + 增强型地热系统　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：化石能源枯竭、环境污染加剧是我们亟待解决的现实问题。清洁无污染、可再生的地热资源近年来受到广泛关注和研究。水热型地热资源温度较低、开发深度较浅,目前利用技术成熟。干热岩地热资源开采的方法为增强型地热系统(Enhanced Geothermal System,EGS)。注入流体生产参数(流速和温度)、人工压裂储层渗透率、注入-开采井的井网分布(井数、井型、井间距等)的优化设计是EGS实际工程建设需要解决的关键问题。本文采用数值模拟方法,进行了以下方面的工作:(1)在总结干热岩地热资源赋存地质条件基础上,结合云南省腾冲县热海热田地质背景,建立了EGS采热过程的数值模拟模型。(2)利用正交设计方法,开展“数值模拟实验”,分析了井间距、注入流体温度和流量、储层渗透率等因素对EGS采热性能的影响规律。结果表明:井间距是影响采热性能的最主要因素,并且对注入水温度和流量、储层渗透率的确定有显著影响。井间距较小时,系统运行寿命随注入水温度增高而增加,储层的渗透率也可以较低;井间距足够大时,注入温度的高低对系统运行寿命影响不大,渗透率变化对采热温度也几乎没有影响。(3)比较了井型(直井、水平井)和井网分布(五点法、七点法、九点法)对EGS采热性能的影响。结果表明:直井采热系统中,开采井数对水渗流的均匀性有影响,渗流不均匀将导致储层热量不能充分开采;注入井数对水渗流面积和渗流量有影响,渗流面积小、渗流量大的系统运行寿命较短;水平井采热系统中,开采井数增加时开采出的热水量不会变,但是会增加水的渗流面积,从而增加可采热量;注入井数增加时开采出的热水量会减少,并且使区域可采热量流失。
[Abstract]:The depletion of fossil energy and the intensification of environmental pollution are the practical problems to be solved urgently. Clean and non-polluting, renewable geothermal resources have received extensive attention and research in recent years. Hydrothermal geothermal resources have low temperature and shallow exploitation depth. The method of exploitation of dry hot rock geothermal resources is enhanced Geothermal system (EGS). The optimization design of injection fluid production parameters (velocity and temperature), artificial fracturing reservoir permeability, well pattern distribution (number of wells, well types, well spacing, etc.) are the key problems to be solved in EGS construction. In this paper, numerical simulation method is used to carry out the following work: (1) on the basis of summing up the geological conditions of geothermal resources in dry hot rock, combined with the geological background of hot sea thermal field in Tengchong County, Yunnan Province, The numerical simulation model of EGS heat recovery process is established. (2) by using orthogonal design method, numerical simulation experiments are carried out, and the effects of well spacing, injection fluid temperature and flow rate, reservoir permeability and other factors on the heat recovery performance of EGS are analyzed. The results show that well spacing is the most important factor affecting thermal recovery performance, and it has a significant effect on the determination of injection water temperature and flow rate and reservoir permeability. When the interval between wells is small, the operating life of the system increases with the increase of injection water temperature, and the permeability of reservoir can also be lower, and when the interval between wells is large enough, the level of injection temperature has little effect on the operating life of the system. (3) the effects of well pattern (vertical well, horizontal well) and well pattern distribution (five point method, seven point method, nine point method) on heat recovery performance of EGS are compared. The results show that in the heat recovery system of vertical wells, the number of wells produced has an effect on the uniformity of water seepage, and the uneven seepage will lead to insufficient exploitation of reservoir heat, while the number of injection wells has an effect on the area and flow rate of water percolation, and the seepage area is small. In the heat recovery system of horizontal wells, the quantity of hot water produced will not change when the number of wells is increased, but the seepage area of water will be increased, thus the recoverable heat will be increased. As the number of injection wells increases, the amount of hot water produced will decrease and the recoverable heat will be lost.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P314

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