Analytical Solutions for Predicting and Optimizing Geothermal Energy Extraction from an Enhanced Geothermal System with a Multiple Hydraulically Fractured Horizontal-Well Doublet

2021 ◽  
Author(s):  
Satuk Bugra Akdas ◽  
Mustafa Onur
Keyword(s):  
Analytical Solutions ◽  
Geothermal Energy ◽  
Horizontal Well ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Energy Extraction ◽  
Fractured Horizontal Well

Evaluation of geothermal energy extraction in Enhanced Geothermal System (EGS) with multiple fracturing horizontal wells (MFHW)

2020 ◽  
Vol 151 ◽  
pp. 1339-1351 ◽  
Author(s):  
Facheng Gong ◽  
Tiankui Guo ◽  
Wei Sun ◽  
Zhaomin Li ◽  
Bin Yang ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Horizontal Wells ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Energy Extraction

Geothermal

2020 ◽  
pp. 363-402
Author(s):  
Paul F. Meier
Keyword(s):  
Pacific Ocean ◽  
Geothermal Energy ◽  
Power Plants ◽  
Hot Water ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Heating And Cooling ◽  
The Earth ◽  
The Pacific ◽  
The Pacific Ocean

Geothermal energy is heat taken from below the surface of the earth in the form of either steam or hot water. This energy can be used to generate electricity, but also has use in heating and cooling homes and some direct uses, such as gold mining, food dehydration, and milk pasteurizing. There are four basic types of geothermal power plants including steam, flash, binary, and enhanced geothermal system (EGS). The first three rely on permeable aquifers that have water flowing through them such that hot water or steam can be extracted. EGS, however, extracts heat from deep in the earth by injecting water and creating artificial fractures in the rock. A great deal of the world’s potential for geothermal energy exists in the so-called Ring of Fire, a ring of volcanoes around the Pacific Ocean.

Performance of geothermal energy extraction in a horizontal well by using CO2 as the working fluid

2018 ◽  
Vol 171 ◽  
pp. 1529-1539 ◽  
Author(s):  
Fengrui Sun ◽  
Yuedong Yao ◽  
Guozhen Li ◽  
Xiangfang Li
Keyword(s):  
Geothermal Energy ◽  
Horizontal Well ◽  
Working Fluid ◽  
Energy Extraction

Enhanced Geothermal System Model for Flow through a Stimulated Rock Volume

2021 ◽  
Author(s):  
Leila Zeinali ◽  
Christine Ehlig-Economides ◽  
Michael Nikolaou
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Plant ◽  
Horizontal Well ◽  
Numerical Models ◽  
Horizontal Wells ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Well Pattern ◽  
Flow Through

Abstract An Enhanced Geothermal System (EGS) uses flow through fractures in an effectively impermeable high-temperature rock formation to provide sustainable and affordable heat extraction that can be employed virtually anywhere with no need for a geothermal reservoir. The problem is that there is no commercial application of this technology. The three-well pattern introduced in this paper employs a multiple transverse fractured horizontal well (MTFHW) drilled and fractured in an effectively impermeable high-temperature formation. Two parallel horizontal wells drilled above and below or on opposing sides of the MTFHW have trajectories that intersect its created fractures. Fluid injected in the MTFHW flows through the fractures and horizontal wells, thus extracting heat from the surrounding high-temperature rock. This study aims to find the most cost-effective well and fracture spacing for this pattern to supply hot fluid to a 20-megawatt power plant. Analytical and numerical models compare heat transfer behavior for a single fracture unit in an MTFHW that is then replicated along with the horizontal well pattern(s). The Computer Modeling Group (CMG) STARS simulator is used to model the circulation of cold water injected into the center of a radial transverse hydraulic fracture and produced from two horizontal wells. Key factors to the design include formation temperature, the flow rate in fractures, the fractured radius, spacing, heat transfer, and pressure loss along the wells. The Aspen HYSYS software is used to model the geothermal power plant, and heat transfer and pressure loss in wells and fractures. The comparison between analytical and numerical models showed the simplified analytical model provides overly optimistic results and indicates the need for a numerical model. Sensitivity studies using the numerical model vary the key design factors and reveal how many fractures the plant requires. The economic performance of several scenarios was investigated to minimize well drilling and completion pattern costs. This study illustrates the viability of applying known and widely used well technologies in an enhanced geothermal system.

Designing multi-well layout for enhanced geothermal system to better exploit hot dry rock geothermal energy

2015 ◽  
Vol 74 ◽  
pp. 37-48 ◽  
Author(s):  
Jiliang Chen ◽  
Fangming Jiang
Keyword(s):  
Geothermal Energy ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Hot Dry Rock

Performance analysis of pinnate horizontal well in enhanced geothermal system

2021 ◽  
pp. 117799
Author(s):  
Jingxuan Xie ◽  
Jiansheng Wang ◽  
Xueling Liu
Keyword(s):  
Performance Analysis ◽  
Horizontal Well ◽  
Geothermal System ◽  
Enhanced Geothermal System

Impact of convective cooling on pore pressure and stresses around a borehole subjected to a constant flux: Implications for hydraulic tests in an enhanced geothermal system reservoir

2020 ◽  
Vol 8 (2) ◽  
pp. SG13-SG20 ◽  
Author(s):  
Zhiqiang Fan ◽  
Rishi Parashar ◽  
Zhi-He Jin
Keyword(s):  
Pore Pressure ◽  
Analytical Solutions ◽  
Cold Water ◽  
Borehole Wall ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Inversion Algorithm ◽  
Thermoelastic Effect ◽  
Hydraulic Test ◽  
Convective Cooling

Hydraulic tests are commonly performed prior to reservoir stimulation to determine the natural permeability of the enhanced geothermal system (EGS), which typically involves injection of cold water at low rates into the hot target EGS reservoir and measurement of the surface pressure, flow rate, and thermal drawdown simultaneously. Interpretation and analysis of the data collected during a hydraulic test are largely based on fitting type curves generated from analytical solutions. We have formulated a geomechanical model for hydraulic tests in a thermoporoelastic EGS reservoir in which the open-hole section of the borehole wall is subjected to a constant-rate flux and convective cooling. We derive the analytical solutions for injection induced axisymmetric deformation, temperature drawdown, pore pressure, and stresses in the Laplace domain, and we obtain time-domain solutions using the Stehfest inversion algorithm. We evaluate numerical examples to illustrate the competition between the thermoelastic effect and the poroelastic effect in controlling temperature, pore pressure, and stresses around the borehole wall. The numerical results indicate that temperature drawdown at the borehole wall would be significantly overestimated if a constant temperature boundary condition instead of convective cooling is used. At early times, injection induced hoop stress/pore pressure is partially offset by the corresponding ones induced by convective cooling. At late times, convective cooling plays a marginal role in influencing pore pressure and stress around the borehole. The analytical solutions are helpful to address the thermohydromechanical coupling mechanisms controlling pressure perturbations during hydraulic tests conducted in an EGS reservoir.

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