Enhanced Geothermal Systems Research Articles

Advancements in Geothermal Energy: Extraction Methods, Utilization Practices, and Future Improvements

Abstract. As a matter of fact, on account of the increasing energy requirements in the world and pressure on environmental conservation globally, geothermal power is becoming an increasingly important source of energy especially in recent years. With this in mind, the objective of this study is to examine as well as investigate developments in energy focusing on extraction techniques, utilization practices and future trends. At the same time, it also scrutinizes how Enhanced Geothermal Systems (EGS) have been evolving and their capabilities in terms of accessing reserves as well as integration with other sustainable energy types. Notably, advances in drilling and heat transfer technologies have significantly improved efficiency of systems. According to the analysis, the report concludes that despite existing challenges such as costs, geothermal energys negligible environmental impact coupled with technological advancements has positioned it as a worthwhile green alternative for tomorrow. These results shed light on guiding further exploration of geothermal energy.

Impact of dual-fracture location on heat extraction from Enhanced geothermal system in low-permeability reservoirs

As environmental and economic issues exacerbated by traditional fossil fuels intensify, Dry Hot Rock geothermal energy has garnered significant attention due to its immense potential. Current research predominantly focuses on the heat extraction effectiveness in complex fractures within Enhanced Geothermal Systems, with relatively less emphasis on fluid behavior between large fractures. This study employs finite element software to establish a multi-horizontal well model in a low permeability reservoir (5 × 10-17 m2), analyzing the impact of different spatial configurations of two fractures on fluid flow, heat transfer, and heat extraction efficiency. The results indicate that fractures are the primary channels for fluid flow in low permeability reservoirs. Optimal heat extraction occurs when fractures are parallel, spaced 100 m apart, and perpendicular to the horizontal well, with significant threshold effects of fracture spacing and angle on temperature distribution. The highest heat extraction is achieved at a 37° intersection angle of fractures at the production well. Over a 60-year production period, reservoir extraction degrees for parallel or intersecting fractures range from 8 % to 15 %, while that for fracture communication between injection and production well horizontal segments is only 1.91 % to 3.01 %. Under the optimal injection scenario, cumulative 60-year heat production for parallel, intersecting, and communicating fractures is 2.13 × 1018J, 2.20 × 1018J, and 2.22 × 1018J, respectively, with the best heat extraction efficiency when fractures communicate. Additionally, under constant flow rate and inlet temperature, outlet temperature and system thermal power show near-linear declines, while reservoir extraction degree rises linearly. This study provides crucial theoretical support and practical guidance for the efficient extraction of geothermal energy.

Optimizing Production Well Geometry in the Utah FORGE Geothermal Project Using Machine Learning and Fluid Flow Modeling

This study addresses the critical challenge of optimizing well placement in Enhanced Geothermal Systems (EGS), specifically within the framework of the Utah FORGE geothermal project, as part of the 2023 Society of Petroleum Engineers (SPE) Geothermal Datathon. Effective well placement is essential for enhancing geothermal production efficiency and maximizing resource utilization. We employed a discrete fracture network (DFN) modeling approach, utilizing the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm from the Scikit-Learn library to analyze microseismic event location data. Through rigorous simulations conducted in the open-source GeoDT fluid flow simulator, we identified an optimal production well configuration characterized by a spacing of 400 m, an injection rate of 0.03 m³/s, and alignment parameters that significantly improve thermal recovery. The results indicate a projected net present value (NPV) of $75 million over a 20-year operational horizon, underscoring the economic potential of optimized well placement strategies. This study offers valuable insights for the operation of the FORGE geothermal site. More importantly, it exclusively utilizes open-source tools, enhancing accessibility and adaptability for the broader geothermal community.

Comparative Analysis and Application of Mass and Heat Transfer Simulation in Fractured Reservoirs Based on Two Fracture Models

The projection-based embedded discrete fracture model (pEDFM) and its counterpart, the embedded discrete fracture model (EDFM), have become standard tools for the depiction of the fractures in reservoir simulations. Despite their widespread use, there are still some unclear areas in modeling the complex processes of mass and heat transfer within fractured reservoirs, particularly in both single-phase and multiphase flow scenarios. Our research introduces a numerical methodology for simulating the mass and heat transfer in fractured reservoirs which is developed by extending the framework of the pEDFM and EDFM. To gauge the effectiveness of these models, we devised two cases which were designed to evaluate the adaptability of the pEDFM and EDFM in scenarios involving an ultra-low permeability fracture or a high permeability fracture under single-phase and multiphase conditions. By using local grid refinement (LGR) as a reference, the results of the pEDFM were in reasonably good agreement with the LGR in terms of pressure, temperature, and saturation distributions. This comparison suggests that the pEDFM has a significant advantage in depicting the mass and heat transfer at the matrix–fracture interface compared to the EDFM. Furthermore, a comprehensive analysis of the flow trajectories in both the pEDFM and EDFM provided a reasonable explanation for their differences. Furthermore, the numerical applications involving the heat extraction of Enhanced Geothermal Systems (EGSs) and the water flooding in fractured reservoirs illustrate the adaptability of the pEDFM in the numerical simulation for complex geological conditions. The insights and conclusions obtained in this paper can enhance our understanding of the distinctions between the pEDFM and EDFM, aiding in the selection of the most suitable method for characterizing the fractures in numerical simulations.

Research Progress on CO2 as Geothermal Working Fluid: A Review

With the continuous increase in global greenhouse gas emissions, the impacts of climate change are becoming increasingly severe. In this context, geothermal energy has gained significant attention due to its numerous advantages. Alongside advancements in CO2 geological sequestration technology, the use of CO2 as a working fluid in geothermal systems has emerged as a key research focus. Compared to traditional water-based working fluids, CO2 possesses lower viscosity and higher thermal expansivity, enhancing its mobility in geothermal reservoirs and enabling more efficient heat transfer. Using CO2 as a working fluid not only improves geothermal energy extraction efficiency but also facilitates the long-term sequestration of CO2 within reservoirs. This paper reviews recent research progress on the use of CO2 as a working fluid in Enhanced Geothermal Systems (EGS), with a focus on its potential advantages in improving heat exchange efficiency and power generation capacity. Additionally, the study evaluates the mineralization and sequestration effects of CO2 in reservoirs, as well as its impact on reservoir properties. Finally, the paper discusses the technological developments and economic analyses of integrating CO2 as a working fluid with other technologies. By systematically reviewing the research on CO2 in EGS, this study provides a theoretical foundation for the future development of geothermal energy using CO2 as a working fluid.

Study on optimization of thermal injection parameters in fractured reservoirs of HDR

ABSTRACT To improve the heat recovery of hot dry rock (HDR) and realize the efficient and sustainable development of geothermal energy, it is necessary to analyse the factors affecting the heat recovery performance of HDR fractured reservoir. In this paper, a numerical model of heat recovery in fractured reservoirs with HDR is established. The effects of injection parameters on the heat recovery performance of the Enhanced Geothermal System (EGS) are compared and analysed by means of the average temperature, heat extraction rate, production temperature and heat recovery power of matrix rocks at different locations. The influence degree of injection flow rate and injection temperature on production temperature was analysed by grey correlation analysis method. The results showed that reducing the injection temperature is beneficial to fully extract the heat energy in the rock mass. The injection flow rate is positively correlated with the heat extraction rate and negatively correlated with the extraction temperature. In this simulation scheme, the optimal results are as follows: injection temperature is 298.15K, injection flow is 12 kg/s, and the influence of injection flow on production temperature is greater than that of injection temperature. This study provides a theoretical basis for the development and utilization of geothermal energy in HDR and provides a reference for the design of engineering operation parameters.

Modeling proppant transport and settlement in 3D fracture networks in geothermal reservoirs

In this paper, we develop an efficient proppant transport model using the Eulerian-Eulerian approach for simulating proppant transport in fractures and 3D fracture networks in geothermal reservoirs. The proposed model accounts for proppant settling, pack/bed formation, bridging/screenout, proppant concentration effect, fracture wall effect, and the transition from Poiseuille flow (fracture channel) to Darcy flow (proppant pack). Notably, the heat transfer process and its impact on proppant transport are also considered—a facet often overlooked in previous proppant transport models. A three-dimensional displacement discontinuity method (3D DDM) that incorporates the stress shadow effect is employed to generate the fracture geometry. The governing equations for slurry flow, proppant transport, and heat transfer are discretized and solved using the finite volume method (FVM). The model is verified against analytical solutions and published experimental data, demonstrating good agreement with these references. To demonstrate the proposed model, we applied it to both low-temperature (depleted hydrocarbon wells) and high-temperature (dry hot rocks) enhanced geothermal systems (EGS). The simulation results highlight the significant influence of reservoir temperature on proppant transport and settlement in a reservoir environment. Heating of the slurry by higher temperature reservoir rocks reduces fluid viscosity and accelerates proppant settling, thereby shortening the transport distance and reducing the coverage area of the proppant. Both ultra-light and micro-proppant are effective in mitigating proppant settlement in enhanced geothermal systems. However, proppant is susceptible to bridging at fracture intersections, where the fracture widths are narrower due to more pronounced stress shadow effects in these areas. Consequently, the use of micro-proppant could offer substantial benefits over ultra-light proppant in enhancing proppant coverage area in enhanced geothermal systems.

Thermo-hydro-mechanical fully coupled model for enhanced geothermal system and numerical solution method based on finite volume method

Enhanced geothermal system (EGS) has been widely used to improve the production performance of geothermal reservoirs. Extracting the heat energy from geothermal reservoirs involves complex multi-physical process, referred to as the thermal–hydro–mechanical (T–H–M) coupling. To optimize the production schedule, numerical simulator is an important tool for EGS development. However, the numerical solution method based on FVM is rare in the literature. To address this gap, in this study, we derive the mathematical equations of fully coupled T–H–M model. Then, the solution method based on FVM is established. Next, the its accuracy is verified against two cases. Last, the proposed method is applied to an EGS model to simulate the heat extraction process. The evolutions of pressure, temperature, and fracture aperture are analyzed. The effects of controlling parameters of the extraction efficiency are discussed. Results indicate that increasing the injection rate will reduce the lifespan of EGS but accelerate the energy extraction. Increasing the injection temperature can promote the heat extraction to limited extent. Increasing the matrix permeability can significantly improve the extraction efficiency. Enlarging the fracture spacing can enlarge the heat recovery rate. In addition, reducing the fracture permeability can avoid thermal shortcut and improve the production performance.

Downhole flow control: A key for developing enhanced geothermal systems in horizontal wells

Field evidence indicates that only a few large fractures in enhanced geothermal systems (EGS) may dominate fluid flow and lead to the development of thermal short-circuiting. This problem would worsen in heat harvesting through horizontal wells with abundant fractures (induced or natural ones). To limit flow shortcuts that may cause early thermal breakthroughs, we propose a temperature-sensitive flow management system and explore its potential benefits during the development of EGS in horizontal wells. The proposed downhole flow management system consists of sensors for real-time temperature monitoring, and flow control devices for adjusting injection distribution in the wellbore. We evaluate the performance of such systems over 50 years of operation by numerical analysis. The results indicate that, when the proposed system is utilized, the produced fluid temperature will be increased by up to 60 K for a field-scale example. Besides, the application of the proposed flow management system can increase the cumulative heat extraction by up to 48.25 % (0.69 × 1016 J) after 50 years. The heat extraction efficiency can be improved by up to 94.16 %. During the EGS operation, it is suggested to implement multi-stage fluid control, but it is not recommended to reopen the fluid injection that has been previously shut down. Finally, the flow management system can mitigate the negative impacts of geological heterogeneities or the heterogeneity in fracture hydraulic conductivities. This paper proposes a new concept of flow management to integrate horizontal wells into efficient EGSs for power generation and heat extraction in the future.

How beliefs about tampering with nature influence support for enhanced geothermal systems: A cross-national study.

Many believe that enhanced geothermal systems (EGS) can greatly increase the extraction of geothermal energy worldwide, helping to decarbonize heat and electricity production. Effective communication is key to realizing the potential of EGS, yet we currently know little about how the public perceives this emerging technology. This exploratory study contributes to the literature with a cross-national survey in the United States (n=1003) and Switzerland (n=1028), two countries with active EGS projects. Specifically, we explore how EGS support relates to beliefs about the deep underground and perceptions of EGS as tampering with nature. The results show that respondents tend to perceive the deep underground as part of nature, dangerous, and unpredictable. The majority are positive about using the deep underground as a resource, although there were variations regarding specific underground activities. In both countries, EGS support is greater for respondents who perceive the underground as something for human use, perceive more benefits than risks from EGS, and support their country's transition to renewable energy. In Switzerland, EGS support is positively related to trust in industry developers and negatively related to perceptions that EGS is tampering with nature. The results offer novel theoretical insights into perceptions of the deep underground in relation to energy development. From a practical standpoint, the results suggest that those seeking to develop EGS may want to consider how to familiarize individuals with current subsurface energy activities, including efforts to protect the underground from unwanted consequences of "tampering," alongside engaging in discussions about the risks and benefits of EGS.

Managing Induced Seismicity Risks From Enhanced Geothermal Systems: A Good Practice Guideline

AbstractGeothermal energy is a green source of power that could play an important role in climate‐conscious energy portfolios; enhanced geothermal systems (EGS) have the potential to scale up exploitation of thermal resources. During hydraulic fracturing, fluids injected under high‐pressure cause the rock mass to fail, stimulating fractures that improve fluid connectivity. However, this increase of pore fluid pressure can also reactivate pre‐existing fault systems, potentially inducing earthquakes of significant size. Induced earthquakes are a significant concern for EGS operations. In some cases, ground shaking nuisance, building damages, or injuries have spurred the early termination of projects (e.g., Basel, Pohang). On the other hand, EGS operations at Soultz‐sous‐Forêts (France), Helsinki (Finland), Blue Mountain (Nevada, USA), and Utah FORGE (USA) have adequately managed induced earthquake risks. The success of an EGS operation depends on economical reservoir enhancements, while maintaining acceptable seismic risk levels. This requires state‐of‐the‐art seismic risk management. This article reviews domains of seismology, earthquake engineering, risk management, and communication. We then synthesize “good practice” recommendations for evaluating, mitigating, and communicating the risk of induced seismicity. We advocate for a modular approach. Recommendations are provided for key technical aspects including (a) a seismic risk management framework, (b) seismic risk pre‐screening, (c) comprehensive seismic hazard and risk evaluation, (d) traffic light protocol designs, (e) seismic monitoring implementation, and (f) step‐by‐step communication plans. Our recommendations adhere to regulatory best practices, to ensure their general applicability. Our guidelines provide a template for effective earthquake risk management and future research directions.

Techno-economic optimization of enhanced geothermal systems with multi-well fractured reservoirs via geothermal economic ratio

Enhanced Geothermal System (EGS) shows vast potential for exploiting deep geothermal energy sources, although its techno-economic feasibility remains uncertain. The current research challenge lies in the absence of a reliable tool to rapidly evaluate the economic gains associated with the design of geothermal reservoirs. This study aims to develop an evaluation metric to assess the geothermal economic ratio of EGS. The efficacy, practicality, and simplicity of the proposed metric were demonstrated through its application to reservoir cases involving six fracture structures and four influencing parameters. The geothermal economic ratio of the system was enhanced through the augmentation of injection mass and the expansion of production well spacing. However, it was reduced by higher injection temperatures and wider primary fracture apertures. Using response surface design, the optimal parameters were found to be an injection temperature of 24 °C, an injection mass of 30 kg/s, a primary fracture aperture of 6.192 mm, and a production well spacing of 200 m. These parameters facilitated a reservoir heating efficiency of 0.322, a reservoir flow efficiency of 0.514, and a geothermal economic ratio of 1.026 × 10−20. The proposed metric and results would offer a concise and informative analysis of the market potential of EGS.

Harnessing the heat below: Efficacy of closed-loop systems in the cooper basin, Australia

Transitioning to renewable energy is vital for combating climate change and reducing CO2 emissions. Geothermal energy, sourced from the earth's crust, presents a promising alternative. While shallow geothermal energy extraction grows steadily, tapping into deep Hot Dry Rock reservoirs poses challenges. Sustainable utilization of deep geothermal energy is crucial for large-scale electricity generation. Australia's Habanero enhanced geothermal system (EGS) projects faced obstacles due to complex fracture networks. Borehole heat exchangers (BHEs) offer a solution, circulating a working fluid without direct contact with geofluids. This study assesses coaxial BHEs' feasibility in the Habanero reservoir using a 2D axisymmetric model (2D-AM), comparing it with a simpler 1D depth-integrated model (1D-DIAM). Both models yield similar outcomes. Additionally, results indicated that the production temperature of the coaxial BHE exponentially decreased from 250 °C to 100 °C within 10 h, rendering energy recovery for electricity generation unsuitable after 10 h of operation. The study proposes an energy recovery cycle of 10 h followed by a 110-h shutdown. Injection temperatures and flow rates significantly impact production efficiency, while steel casing's thermal conductivity has minimal influence on heat exchanger performance.

The impact of effective fractured rock mass properties on development of flow channeling in enhanced geothermal systems

Controlling the distribution of working fluid in an Enhanced Geothermal System (EGS) is crucial to prevent early thermal breakthrough and sustain the initial heat drainage area. Over time, working fluid flow may localize to a small area if fracture permeability increases non-uniformly, and efforts are not made to control the flow distribution. This scenario can potentially lead to mechanical reopening of hydraulic fractures, flow channeling, and thermal short-circuiting. However, current models neglect the nonlinear and inelastic deformation of fractured rock masses on EGS coupled thermo-mechanical response. The objective of this work is to estimate and predict the likelihood of thermal short-circuiting by flow-channeling in an EGS reservoir composed of rock and compliant natural fractures. We utilize three dimensional numerical solutions with reservoir properties based on effective medium theory of fractured rocks to achieve this objective. The results show that presence of natural fractures considerably changes the EGS response to thermal destressing, compared to linear poroelastic models. Flow channeling and short-circuiting, resulting in early thermal breakthrough, are more likely to occur in sparsely fractured reservoirs with stiff and strong natural fractures. Conversely, short-circuiting is unlikely in densely fractured reservoirs where thermal strains are absorbed by natural fracture opening and shear sliding rather than by rock matrix contraction. Estimation of natural fracture density is crucial in long-term forecasting and prediction of EGS power output. Accurate fracture characterization could decisively impact the fate of a project.

Assessing Potential Seismic Hazard in Enhanced Geothermal Systems: Insights from Comparing Gonghe and Pohang Reservoirs

Abstract Evaluating and predicting the seismic hazard induced by fluid injection in enhanced geothermal systems (EGSs) is critical for safe and effective operations. This study compares the Gonghe project, a pioneering EGS initiative in China, with the well-studied Pohang EGS in South Korea, within a broader context of global fluid injection practices. We assessed the potential seismic hazard at these two sites based on their seismogenic indices (Σ). We find that Σ of the Gonghe EGS generally decreases from 0.4 to −0.7, consistent with the typical ranges of Σ in EGS sites, including Pohang. Our results indicate that real-time Σ is a more reliable measure for assessing seismic hazard in Gonghe because it offers insights into the maximum magnitude, exceedance probabilities, and expected numbers of earthquakes. Conversely, in Pohang, maximum Σ proves more effective for seismic hazard assessment. However, predicting the seismic hazard after the Mw 3.2 earthquake in Pohang remains challenging, particularly for the runaway rupture associated with the subsequent Mw 5.5 earthquake, highlighting the complexities involved. This study suggests that the use of real-time Σ is viable for assessing seismic hazard in EGS reservoirs characterized by descending Σ and seismic injection efficiency. Conversely, for reservoirs with ascending Σ and seismic injection efficiency, such as Pohang, maximum Σ could offer better insights into seismic hazard assessment, although precise earthquake magnitude constraints may be elusive due to dominant tectonic influences.

Correction: Analysis of Comparative Thermo-Hydraulic Performance of sCO2 and H2O as Heat-Exchange Fluids in Enhanced Geothermal Systems

Correction: Analysis of Comparative Thermo-Hydraulic Performance of sCO2 and H2O as Heat-Exchange Fluids in Enhanced Geothermal Systems

The effect of stress barriers on unconventional-singularity-driven frictional rupture

Whether or not energy dissipation is localized in the vicinity of the rupture tip, and whether any distal energy dissipation far from the crack tip has a significant influence on rupture dynamics are key questions in the description of frictional ruptures, in particular regarding the application of Linear Elastic Fracture Mechanics (LEFM) to earthquakes. These questions are investigated experimentally using a 40-cm-long experimental frictional interface. Three independent pistons apply a normal load with a fourth piston applying a shear load, enabling the application of a heterogeneous stress state and stress barriers. After loading the frictional interface to a near-critical state, subsequent unloading of one normal-load piston leads to dynamic ruptures which propagate into the heterogeneous stress fields. The ruptures in these experiments are found to be driven by unconventional singularities, characterized by an ever-increasing breakdown work with slip, and as a result do not conform to the assumptions of LEFM. As these experimental stress barriers inhibit slip, they therefore also reduce the breakdown work occurring outside of the cohesive zone. It is shown that this distal weakening, far from the crack tip, must be considered for the accurate prediction of rupture arrest length. These experiments are performed in the context of a proposed stimulation technique for Enhanced Geothermal Systems (EGSs). It has previously been suggested, through theoretical arguments, that stress barriers could be induced through the manipulation of pore pressure such that there is reduced seismic hazard during the shear stimulation of EGSs. This stimulation technique, known as preconditioning, is demonstrated here to reduce the mechanical energy flux to the crack tip, G, while also increasing the fracture energy, Gc. Preconditioning is shown to be capable of arresting seismic rupture and reducing co-seismic slip, slip velocity, and seismic moment at preconditioning stresses which are reasonably achievable in the field. Due to the fully-coupled nature of seismic rupture and fault slip, preconditioning also reduces distal weakening and its contribution to the propagation of induced seismic ruptures. In a similar vein, heterogeneous pore pressure fields associated with some seismic swarms can be used to explain changes in stress drop within the swarm without recourse to material or total-stress heterogeneity.

Environmental Implications of Ionic Liquid and Deep Eutectic Solvent in Geothermal Application: Comparing Traditional and New Approach Methods.

The significant surge of ionic liquids (ILs) research over the past decade has led to the formation of various novel ionic liquid compounds and their diverse applications. Enhanced geothermal systems (EGS) for geothermal power generation are an emerging IL application as a heat extraction fluid. The once widely held belief in the environmentally friendly characteristics of ionic liquids, mainly due to their insignificant vapor pressure, is now being scrutinized. It has become apparent that while ILs do not readily evaporate into the atmosphere, they are not guaranteed to remain entirely isolated from the environment. Recent attention has been directed toward toxicological studies, including ecotoxicity impacts, with the long-accepted assumption of ILs having low toxicity being invalid. This paper aims to shed light on the toxicity of hexylepyradinium bromide (HPyBr) IL and a deep eutectic solvent (DES) comprising choline chloride with magnesium chloride hexahydrate (ChCl:MgCl2·6H2O) to five test species, an algal species (Raphidocelis subcapitata), the water flea (Ceriodaphnia dubia and Daphina magna), the fathead minnow (Pimephales promelas), and the earthworm (Eisenia fetida), to measure acute and chronic toxicity. Additionally, new approach methods (NAMs) are presented using the fathead minnow embryo and the rainbow trout (Oncorhynchus mykiss) gill cell line and the RTgill-W1 assay to compare sensitivity across species. Overall, ChCl:MgCl2·6H2O displayed lower toxicity, while HPyBr demonstrated higher toxicity, highlighting the need for caution in handling it to prevent harm to aquatic ecosystems. Comparative analysis underscored the potential threat of ChCl:MgCl2·6H2O to aquatic life, highlighting the cumulative effects of the environmental components.

Enhancing geothermal efficiency: Experimental evaluation of a high-temperature preformed particle gel for controlling preferential fluid flow

Enhanced Geothermal System (EGS) reservoirs represent a vital frontier in clean energy production. However, short-circulation flow within these reservoirs can significantly affect their immediate efficiency and long-term viability. Injected cold fluids moving through wide fractures or direct channels between injection and production wells reduce thermal production temperatures, disrupting energy output. Preformed Particle Gels (PPGs) have proven effective in controlling preferential fluid flow in oil and gas reservoirs, effectively regulating fluid movement. This work explores the potential of a novel High-Temperature Preformed Particle Gel (HT-PPG), designed for geothermal applications, to plug fractures in a simulated geothermal reservoir. Core flooding experiments in coated and uncoated sandstone models were conducted under varying HT-PPG sizes, swelling ratios, and fracture widths to determine gel plugging efficiency. Variations in the HT-PPG injection pressure, breakthrough pressure, and residual resistance factor (Frr) were evaluated. Water breakthrough pressures can reach 464.10 psi/ft. While the stable injection pressure of HT-PPG decreased with increasing swelling ratio and fracture width, it was higher in uncoated cores. The HT-PPG significantly sealed the fractures, drastically reducing conductivities to millidarcy levels. This work validates HT-PPG a robust solution to mitigate fluid diversion challenges in sandstone EGS reservoirs, enhancing performance and advancing sustainable geothermal energy production.

Analysis of Comparative Thermo-Hydraulic Performance of sCO2 and H2O as Heat-Exchange Fluids in Enhanced Geothermal Systems

Analysis of Comparative Thermo-Hydraulic Performance of sCO2 and H2O as Heat-Exchange Fluids in Enhanced Geothermal Systems