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增强型地热系统(EGS)是开发深层高温地热能的有效途径.本文在垂直单裂隙模型(SVFM)的基础上构建了平行多裂隙模型(MPFM),验证了其可靠性及优越性,创新地提出了换热单元体(HTU)的概念,将对整体热储层的研究集中于采热基本单元上,并利用此模型对EGS采热过程中裂隙流体及热储层温度场的演化进行模拟.基于介质分类,将采热的影响因素分为流体和岩体.本文针对岩体热储层分别设计多组案例,分析了岩体HTU尺寸及储层初始温度对釆热的影响.结果表明,HTU的厚度与流体产出温度呈负相关,但与热储层的热采率呈正效应;HTU的长度与采出温度和热储寿命呈正相关;热储层的初始温度也与流体采出温度呈正相关,对热储寿命影响不大.因此,热储层激发越充分,对流换热越充分,采热效率越高.注采策略应与热储层的激发情况相配合,才能取得较好的热开采效果.
Enhanced geothermal system (EGS) is an effective way to develop geothermal energy in deep high temperature.This paper builds parallel multi-fracture model (MPFM) on the basis of vertical single fracture model (SVFM), verifies its reliability and superiority, The concept of heat exchange unit (HTU) was put forward. The study on the whole thermal reservoir was focused on the basic unit of heat recovery, and the model was used to simulate the evolution of temperature field of fissured fluid and thermal reservoir during EGS heating Based on the classification of media, the influencing factors of heat recovery are divided into fluid and rock mass.In this paper, multiple sets of cases are designed respectively for thermal reservoir of rock mass, and the influence of HTU size of rock mass and reservoir initial temperature on heat removal is analyzed. , The thickness of HTU is negatively correlated with the temperature of fluid output, but it has a positive effect with the thermal recovery rate of HTF. The length of HTU is positively correlated with the recovery temperature and thermal storage life. The initial temperature of thermal reservoir is also similar to that of fluid The temperature is positively correlated and has little effect on the thermal storage life.Therefore, the more fully the thermal reservoir is excited, the more convective heat transfer, the higher the heat recovery efficiency.The injection and recovery strategy should be matched with the thermal reservoir stimulation to achieve better Thermal mining effect.