Principle and application of OpenGeoSys for geothermal energy sustainable utilization

doi:10.13745/j.esf.2020.1.18

Abstract

Abstract:

Numerical simulation is very useful in utilizing large scale geothermal energy, predicting reservoir response and optimizing exploitation procedure. Here we describe the OpenGeoSys (OGS) software used to simulate the complex processes in geoscience and hydrological applications, focusing on its application in geothermal energy utilization. OGS is based on an object-oriented finite element method concept and can deal with numerical simulation of thermo-hydro-mechanical-chemical processes in porous media. Case studies related to shallow geothermal energy (temperature and pressure prediction), hydrothermal energy (optimization on the distance between production well and reinjection well, scaling) and hot dry rock (hydraulic fracturing, permeability evolution) are shown with the purpose to help managing geothermal energy utilization.

Key words: OGS, multi-fields coupling, geothermal energy, numerical simulation

CLC Number:

P314

KONG Yanlong, HUANG Yonghui, ZHENG Tianyuan, LU Renchao, PAN Sheng, SHAO Haibing, PANG Zhonghe. Principle and application of OpenGeoSys for geothermal energy sustainable utilization[J]. Earth Science Frontiers, 2020, 27(1): 170-177.

Figures/Tables 14

Fig.1 The coupling of thermo-hydro-mechanical-chemical processes by OGS. Modified after [4].

Table 1 Parameters in the coupling equations of OGS

量符号	量名称及单位	量符号	量名称及单位
$n →$	外边界的外法线方向单位矢量	Γ_n	Neumann边界条件
$с$	流体比热/(J·m^-3·K^-1)	q^к	源汇项
$ρ$	流体密度/(kg·m^-3)	$Ф$	孔隙度
T	流体温度/℃	ρ_β	β相的密度/(kg·m^-3)
K	岩石导热系数/(W·m^-1·K^-1)	S_β	β相的饱和度
q	热源/(W·m^-2)	$X β к$	组分к在β相中的质量分数
h_β	β相的热焓	$κ →$	绝对渗透率张量
$σ →$	应力张量	κ_rβ	β相的相对渗透率
$g →$	重力加速度/(m·s^-2)	μ_β	β相的黏度/(Pa·s)
$σ$	主应力/Pa	P_β	β相的压力/Pa
S^l	液相饱和度	$D → β к$	组分к在β相中扩散系数
S^ɡ	气相饱和度	G°_p_,_T	定温压下系统吉布斯函数变化
p^l	液相压强/Pa	R	理想气体常数
p^ɡ	气相压强/Pa	$K p, T$	定温压下的化学平衡常数
I	单位矩阵	$a w, a m$	活度
$β T$	热膨胀系数	$γ i, γ j$	逸度系数
V_n	体积/m³	C_i,C_j	热容
M^к	质量矩阵	$v wj, v ij, v mj, v ɡ j$	反应方程式中的化学计量数
$F → β$ , $F → к$ , $F → β к$	达西流量	$f ɡ$	逸度

Table 1 Parameters in the coupling equations of OGS

量符号	量名称及单位	量符号	量名称及单位
$n →$	外边界的外法线方向单位矢量	Γ_n	Neumann边界条件
$с$	流体比热/(J·m^-3·K^-1)	q^к	源汇项
$ρ$	流体密度/(kg·m^-3)	$Ф$	孔隙度
T	流体温度/℃	ρ_β	β相的密度/(kg·m^-3)
K	岩石导热系数/(W·m^-1·K^-1)	S_β	β相的饱和度
q	热源/(W·m^-2)	$X β к$	组分к在β相中的质量分数
h_β	β相的热焓	$κ →$	绝对渗透率张量
$σ →$	应力张量	κ_rβ	β相的相对渗透率
$g →$	重力加速度/(m·s^-2)	μ_β	β相的黏度/(Pa·s)
$σ$	主应力/Pa	P_β	β相的压力/Pa
S^l	液相饱和度	$D → β к$	组分к在β相中扩散系数
S^ɡ	气相饱和度	G°_p_,_T	定温压下系统吉布斯函数变化
p^l	液相压强/Pa	R	理想气体常数
p^ɡ	气相压强/Pa	$K p, T$	定温压下的化学平衡常数
I	单位矩阵	$a w, a m$	活度
$β T$	热膨胀系数	$γ i, γ j$	逸度系数
V_n	体积/m³	C_i,C_j	热容
M^к	质量矩阵	$v wj, v ij, v mj, v ɡ j$	反应方程式中的化学计量数
$F → β$ , $F → к$ , $F → β к$	达西流量	$f ɡ$	逸度

Fig.2 Flowchart of OGS application and data input requirements. Modified after [4].

Fig.3 The conceptual model of ground source heat pumps in OGS

Fig.4 Verification of the ground source heat pump module in OGS. Adapted from [8].

Fig.5 Verification of the thermo-hydro-mechanical process through point injection test. Adapted from [11].

Fig.6 Pressure and temperature change with distance between the production and re-injection wells after 50 years. Adapted from [12].

Fig.7 Pressure profile along the production well

Fig.8 Change of dissolved carbon dioxide along the production well

Fig.9 Change of inlet and outlet water temperatures in the deep borehole heat exchanger system after long time operation. Adapted from [14].

Fig.10 Vertical displacement in hydraulic fracturing under prescribed injected fluid volume

Fig.11 Comparison between analytical and numerical solutions in terms of hydraulic pressure and crack length vs. injection fluid volume. Adapted from [17].

Fig.12 Schematic diagram of pressure solution at contact surface. Adapted from [19].

Fig.13 Comparison between experimental and simulated results in terms of evolution of hydraulic aperture under varying hydrothermal conditions. Adapted from [19-20].

References 25

[1]	汪集旸, 胡圣标, 庞忠和, 等. 中国大陆干热岩地热资源潜力评估[J]. 科技导报, 2012, 30(32):25-31.
[2]	KONG Y L, PANG Z H, SHAO H B, et al. Recent studies on hydrothermal systems in China: a review[J]. Geothermal Energy, 2014, 2:19. DOI URL
[3]	庞忠和. 地下水运动对地温场的影响: 研究进展综述[J]. 水文地质工程地质, 1987, 14(3):30-34.
[4]	KOLDITZ O, BAUER S, BILKE L, et al. OpenGeoSys: an open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical (THM/C) processes in porous media[J]. Environmental Earth Sciences, 2012, 67(2):589-599. DOI URL
[5]	KOLDITZ O, GÖRKE U J, SHAO H, et al. Thermo-hydro-mechanical/chemical processes in porous media: lecture notes in computational science and engineering[M]. Heidelberg: Springer, 2012: 344.
[6]	KOLDITZ O, SHAO H, WANG W Q, et al. Thermo-hydro-mechanical-chemical processes in fractured porous media: modelling and benchmarking[M]. Heidelberg: Springer, 2016: 217.
[7]	BEIER R A, SMITH M D, SPITLER J D. Reference data sets for vertical borehole ground heat exchanger models and thermal response test analysis[J]. Geothermics, 2011, 40(1):79-85. DOI URL
[8]	ZHENG T Y, SHAO H B, S. SCHELENZ S, et al. Efficiency and economic analysis of utilizing latent heat from groundwater freezing in the context of borehole heat exchanger coupled ground source heat pump systems[J]. Applied Thermal Engineering, 2016, 105:314-326. DOI URL
[9]	EROL S, FRANCOIS B. Freeze damage of grouting materials for borehole heat exchanger: experimental and analytical evaluations[J]. Geomechanics for Energy and the Environment, 2016, 5:29-41. DOI URL
[10]	ESEN H, INALLI M, ESEN Y. Temperature distributions in boreholes of a vertical ground-coupled heat pump system[J]. Renewable Energy, 2009, 34(12):2672-2679. DOI URL
[11]	ZHENG T Y, MIAO X Y, NAUMOV G, et al. A thermo-hydro-mechanical finite element model with freezing and thawing processes in saturated soils for geotechnical engineering[J]. Environmental Geotechnics, 2019, 6:1-13. DOI URL
[12]	KONG Y L, PANG Z H, SHAO H B, et al. Optimization of well-doublet placement in geothermal reservoirs using numerical simulation and economic analysis[J]. Environmental Earth Sciences, 2017, 76(3):118. DOI URL
[13]	AKIN T, GUNEY A, KARGI H. Modeling of calcite scaling and estimation of gas breakout depth in a geothermal well by using PHREEQC [C]//Proceedings of the 40th Workshop on Geothermal Reservoir Engineering. Stanford, California, 2015.
[14]	孔彦龙, 陈超凡, 邵亥冰, 等. 深井换热技术原理及其换热量评估[J]. 地球物理学报, 2017, 60(12):4741-4752.
[15]	TESTER J W, ANDERSON B J, BATCHELOR A S. et al. The future of geothermal energy: impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century[M]. Cambridge: Massachusetts Institute of Technology Press, 2006: 358.
[16]	WATANABE N, WANG W, TARON J, et al. Lower-dimensional interface elements with local enrichment: application to coupled hydro-mechanical problems in discretely fractured porous media[J]. International Journal for Numerical Methods in Engineering, 2012, 90(8):1010-1034.
[17]	YOSHIOKA K, PARISIO F, NAUMOV D, et al. Comparative verification of discrete and smeared numerical approaches for the simulation of hydraulic fracturing[J]. International Journal on Geomathematics, 2019, 10(1):13.
[18]	BOND A, BRUSKY I, CHITTENDEN N, et al. Development of approaches for modelling coupled thermal-hydraulic-mechanical-chemical processes in single granite fracture experiments[J]. Environmental Earth Sciences, 2016, 75(19):1313. DOI URL
[19]	LU R C, NAGEL T, SHAO H, et al. Modeling of dissolution-induced permeability evolution of a granite fracture under crustal conditions[J]. Journal of Geophysical Research: Solid Earth, 2018, 123(7):5609-5627. DOI URL
[20]	YASUHARA H, KINOSHITA N, OHFUJI H, et al. Temporal alteration of fracture permeability in granite under hydrothermal conditions and its interpretation by coupled chemo-mechanical model[J]. Applied Geochemistry, 2011, 26(12):2074-2088. DOI URL
[21]	HUANG Y H, KOLDITZ O, SHAO H B. Extending the persistent primary variable algorithm to simulate non-isothermal two-phase two-component flow with phase change phenomena[J]. Geothermal Energy, 2015, 3(1):13. DOI URL
[22]	HUANG Y H, SHAO H B, WIELAND E, et al. A new approach to coupled two-phase reactive transport simulation for long-term degradation of concrete[J]. Construction and Building Materials, 2018, 190:805-829. DOI URL
[23]	NAGEL T, SHAO H, SINGH A K, et al. Non-equilibrium thermochemical heat storage in porous media: Part 1-Conceptual model[J]. Energy, 2013, 60:254-270. DOI URL
[24]	MIAO X Y, KOLDITZ O, NAGEL T. Modelling thermal performance degradation of high and low-temperature solid thermal energy storage due to cracking processes using a phase-field approach[J]. Energy Conversion and Management, 2019, 180:977-989. DOI URL
[25]	YAPPAROVA A, MIRON G D, KULIK D A, et al. An advanced reactive transport simulation scheme for hydrothermal systems modelling[J]. Geothermics, 2019, 78:138-153. DOI URL