﻿ 流体力学数值模拟方法在增强型地热系统的应用分析 The Application Study of Fluid Dynamic Numerical Simulation Methods on Enhanced Geothermal System

International Journal of Fluid Dynamics
Vol.05 No.02(2017), Article ID:20894,9 pages
10.12677/IJFD.2017.52006

The Application Study of Fluid Dynamic Numerical Simulation Methods on Enhanced Geothermal System

Cheng Gao1, Bingyu Ji1, Rusheng Zhang1, Jun Niu1, Le Zhang2

1Petroleum Exploration and Production Research Institute, SINOPEC, Beijing

2Department of Thermal Engineering, Tsinghua University, Beijing

Received: May 22nd, 2017; accepted: Jun. 5th, 2017; published: Jun. 8th, 2017

ABSTRACT

Enhanced geothermal system (EGS) is a kind of important geothermal resources developing pattern which owns rich resources. EGS has been received great and popular attention from international community and research institutes since it is proposed. This paper conducts analytical research form pore scale simulation method (PSM), core scale simulation method (CSM) and filed scale simulation method (FSM) to illustrate current application status, technical advantage and existing problems. Finally, it is suggested that PSM should be used as the primary model for the EGS simulation. This work pointed out research direction for EGS simulation area.

Keywords:EGS, Fluid Dynamic Numerical Simulation, Pore Scale, Core Scale, Filed Scale

1中国石化石油勘探开发研究院，北京

2清华大学热能工程系，北京

1. 前言

1974年，美国Los Alamos国家实验室在新墨西哥州的芬顿山开始最早的干热岩研究，并建成世界上第一座高温岩体发电站。1993年中国国家地震局在北京房山区进行了干热岩发电的研究试验工作。水通常作为干热岩开采的流动换热工质，随着温度效应日益严重，2000年提出了用CO2代替水作为增强型地热系统中的流动换热工质，附加的CO2埋存的环境效益 [4] 。

Figure 1. Schematic of Enhanced Geothermal System [3]

Table 1. Numerical simulation programs conducted by international geothermal companies

2. 孔隙尺度数值模拟技术

(1)

3. 岩心尺度数值模拟技术

(2)

(3)

(a) 不可渗透壁面光滑裂隙 [7] (b) 可渗透壁面光滑裂隙 [9]

Figure 2. Schematic of features with permeable wall and impermeable wall

4. 场地尺度数值模拟技术

(4)

Cheng和Ghassemi等 [10] [14] 在垂直于流动方向的裂隙内流体温度相同，并且和裂隙-岩石壁面温度相同假设的基础上，得到常物性工质在干热岩储层内的二维单一裂隙、三维平面裂隙内换热的积分方程解。Gringarten等 [11] 得到储层内冷水从下部流过平行竖直裂隙被加热后的出口热水温度的理论解，分析了裂隙间距、裂隙个数对水出口温度和发电量的影响。Mohais等 [15] 将增强型地热系统等效为注入井、具有可渗透壁面的单一水平裂隙和产出井三部分，采用相似解和摄动展开的方法得到具有可渗透壁面裂隙内的速度分布和温度分布，分析了低雷诺数(Re < 7)下Beavers-Joseph滑移边界条件及其重要参数对裂隙内速度分布和温度分布的影响。Fox等 [16] 采用格林函数法得到在交替进行采热和恢复的过程中，含有单个裂隙的理想储层内的传热效应的理论解，并与TOUGH2软件计算的单个裂隙和多个裂隙结果进行对比分析，多裂隙EGS储层更有能力保证较高的出口流体温度。上述的耦合岩石壁面的单一裂隙内的流动换热问题大多基于沿流动方向流体温度和裂隙–岩石交界面温度相同的基本假设，也即局部热平衡的假设。Lu和Xiang [17] 在已有研究的基础上采用裂隙内流体和岩石壁面对流换热系数描述一维假设下的流体温度和岩石壁面的热量交换，分析了单一裂隙内局部非热平衡效应对裂隙出口流体温度的影响，当对流换热系数越小，储层岩石热容和导热系数越大，裂隙内流体和岩石壁面的局部非热平衡效应越明显。Zeng等 [18] 针对Desert Peak地热场地的EGS项目，构建单一竖直裂隙联通注入井和产出井的数值计算模型，采用TOUGH2-EOS1程序计算并分析了裂隙孔隙率、裂隙渗透率、岩层导热系数、工质水的流量和

(a) 单一裂隙 [10] (b) 平行裂隙群 [11] (c) 离散裂隙网络 [12] (d) 等效多孔介质 [13]

Figure 3. Research methods on geothermal reservoir

5. 结论与展望

The Application Study of Fluid Dynamic Numerical Simulation Methods on Enhanced Geothermal System[J]. 流体动力学, 2017, 05(02): 47-55. http://dx.doi.org/10.12677/IJFD.2017.52006

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