Heat production from lab-scale enhanced geothermal systems in granite and gabbro

2020 ◽  
Vol 126 ◽  
pp. 104205 ◽  
Author(s):  
Lianbo Hu ◽  
Ahmad Ghassemi
Keyword(s):  
Heat Production ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems

scholarly journals Thermo-hydro-mechanical modelling study of heat extraction and flow processes in enhanced geothermal systems

2021 ◽  
Vol 54 ◽  
pp. 229-240
Author(s):  
Dejian Zhou ◽  
Alexandru Tatomir ◽  
Martin Sauter
Keyword(s):  
Production Rate ◽  
Flow Rate ◽  
Heat Production ◽  
Analytical Solutions ◽  
Pressure Difference ◽  
Heat Extraction ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Fracture Zones ◽  
Heat Production Rate

Abstract. Enhanced Geothermal Systems (EGS) are widely used in the development and application of geothermal energy production. They usually consist of two deep boreholes (well doublet) circulation systems, with hot water being abstracted, passed through a heat exchanger, and reinjected into the geothermal reservoir. Recently, simple analytical solutions have been proposed to estimate water pressure at the abstraction borehole. Nevertheless, these methods do not consider the influence of complex geometrical fracture patterns and the effects of the coupled thermal and mechanical processes. In this study, we implemented a coupled thermo-hydro-mechanical (THM) model to simulate the processes of heat extraction, reservoir deformation, and groundwater flow in the fractured rock reservoir. The THM model is validated with analytical solutions and existing published results. The results from the systems of single fracture zone and multi-fracture zones are investigated and compared. It shows that the growth of the number and spacing of fracture zones can effectively decrease the pore pressure difference between injection and abstraction wells; it also increases the production temperature at the abstraction, the service life-spans, and heat production rate of the geothermal reservoirs. Furthermore, the sensitivity analysis on the flow rate is also implemented. It is observed that a larger flow rate leads to a higher abstraction temperature and heat production rate at the end of the simulation, but the pressure difference may become lower.

Convective heat transfer of water flowing in intersected rock fractures for enhanced geothermal extraction

2021 ◽  
Author(s):  
Yuedu chen
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Production ◽  
Three Dimensional ◽  
Heat Extraction ◽  
Rock Fractures ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Dead End

<p>Numerous intersected rock fractures constitute the fracture network in enhanced geothermal systems. The complicated convective heat transfer behavior in intersected fractures is critical to the heat recovery in fractured geothermal reservoirs. A series of three-dimensional intersected fracture models are constructed to perform the flow-through heat transfer simulations. The geometries effects of dead-end fractures on the heat transfer are evaluated in terms of intersected angles, apertures, lengths, and the connectivity. The results indicate that annular streamlines appear in the rough dead-end fracture and cause an ellipsoidal distribution of the cold front. Compared to the steady flow in plate dead-end fractures, the fluid flow formed in the rough dead-end fracture enhances the heat transfer. Both the outlet water temperature T<sub>out</sub> and heat production Q present the largest when the intersected angle is 90°. A larger intersected angle and longer length extension of the intersected dead-end fracture, raising T<sub>out</sub> and Q, are beneficial to the heat production, while increasing the aperture is ineffective. Solely increasing numbers of dead-end fractures poses a little increase on T<sub>out</sub> and Q. More significant heat extraction is obtained through connecting these dead-end fractures with the main flow fracture forming the flow network.</p>

scholarly journals Applying Harmonised Geothermal Life Cycle Assessment Guidelines to the Rittershoffen Geothermal Heat Plant

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3820
Author(s):  
Mélanie Douziech ◽  
Lorenzo Tosti ◽  
Nicola Ferrara ◽  
Maria Laura Parisi ◽  
Paula Pérez-López ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Heat Production ◽  
Hot Spot ◽  
Resource Depletion ◽  
Potential Contribution ◽  
Geothermal Systems ◽  
Geothermal Heat ◽  
The Future ◽  
The Impact

Heat production from a geothermal energy source is gaining increasing attention due to its potential contribution to the decarbonization of the European energy sector. Obtaining representative results of the environmental performances of geothermal systems and comparing them with other renewables is of utmost importance in order to ensure an effective energy transition as targeted by Europe. This work presents the outputs of a Life Cycle Assessment (LCA) performed on the Rittershoffen geothermal heat plant applying guidelines that were developed within the H2020 GEOENVI project. The production of 1 kWhth from the Rittershoffen heat plant was compared to the heat produced from natural gas in Europe. Geothermal heat production performed better than the average heat production in climate change and resource use, fossil categories. The LCA identified the electricity consumption during the operation and maintenance phase as a hot spot for several impact categories. A prospective scenario analysis was therefore performed to assess the evolution of the environmental performances of the Rittershoffen heat plant associated with the future French electricity mixes. The increase of renewable energy shares in the future French electricity mix caused the impact on specific categories (e.g., land use and mineral and metals resource depletion) to grow over the years. However, an overall reduction of the environmental impacts of the Rittershoffen heat plant was observed.

scholarly journals Environmentally friendly, rheoreversible, hydraulic-fracturing fluids for enhanced geothermal systems

Geothermics ◽  
2015 ◽  
Vol 58 ◽  
pp. 22-31 ◽  
Author(s):  
Hongbo Shao ◽  
Senthil Kabilan ◽  
Sean Stephens ◽  
Niraj Suresh ◽  
Anthon N. Beck ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Environmentally Friendly ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Fracturing Fluids
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