Modeling of coupled thermal-hydraulic-mechanical-chemical processes for predicting the evolution in permeability and reactive transport behavior within single rock fractures

Ogata, Sho; Yasuhara, Hajime; Kinoshita, Naoki; Cheon, Dae‐Sung; Kishida, Kiyoshi

doi:10.1016/j.ijrmms.2018.04.015

Cited by 45 publications

(30 citation statements)

References 48 publications

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“…The complexity of the mineralogy and geochemistry will result in chemistry gradients that could extend some distance into a fracture and will change over time as dissolution, precipitation and temperature changes occur. Because these gradients and dissolution and precipitation kinetics can be captured in the modeling, the effects of such complex processes on fracture fluid flow can be evaluated [39,40].…”

Section: Discussionmentioning

confidence: 99%

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Dobson

Kneafsey

Nakagawa

et al. 2021

Journal of Energy Resources Technology

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Enhanced Geothermal Systems (EGS) offer the potential for a much larger energy source than conventional hydrothermal systems. Hot, low-permeability rocks are prevalent at depth around the world, but the challenge of extracting thermal energy depends on the ability to create and sustain open fracture networks. Laboratory experiments were conducted using a suite of selected rock cores (granite, metasediment, rhyolite ash-flow tuff, and silicified rhyolitic tuff) at relevant pressures (uniaxial loading up to 20.7 MPa and fluid pressures up to 10.3 MPa) and temperatures (150-250°C) to evaluate the potential impacts of circulating fluids through fractured rock by monitoring changes in fracture aperture, mineralogy, permeability, and fluid chemistry. Because a fluid in disequilibrium with the rocks (deionized water) was used for these experiments, there was net dissolution of the rock sample: this increased with increasing temperature and experiment duration. Thermal-hydrological-mechanical-chemical (THMC) modeling simulations were performed for the rhyolite ash-flow tuff experiment to test the ability to predict the observed changes. These simulations were performed in two steps: a THM simulation to evaluate the effects of compression of the fracture, and a THC simulation to evaluate the effects of hydrothermal reactions on the fracture mineralogy, porosity, and permeability. These experiments and simulations point out how differences in rock mineralogy, fluid chemistry, and geomechanical properties influence how long asperity-propped fracture apertures may be sustained. Such core-scale experiments and simulations can be used to predict EGS reservoir behavior on the field scale.

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Section: Discussionmentioning

confidence: 99%

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Dobson

Kneafsey

Nakagawa

et al. 2021

Journal of Energy Resources Technology

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“…All related parameters are given in Table 2 [32]. [18] is used to calculate the solute transport behavior. Mechanical dispersion and retardation due to sorption are not considered here.…”

Section: Geofluidsmentioning

confidence: 99%

“…For fine-grained porous media, the thermal conduction between fluid and solid is a fast process, resulting in thermal equilibrium between fluid and solid. Thus, by excluding radiation, the effects of thermal convection and conduction define the heat transfer equation as follows [18]: where ρC p eq (J/K/m 3 ) is the equilibrium volumetric heat capacity, λ eq (W/m/K) is the equilibrium thermal conductivity tensor, and Q T (W/m 3 ) is the heat source. These parameters may be defined from composite fluid/solid systems as follows:…”

Section: Energy Conservationmentioning

confidence: 99%

“…Based on experimental studies, several numerical studies have quantified the significant contribution of coupled THMC processes to EGS reservoir production decline. Pressure solution and chemical precipitation are found to be key mechanisms for permeability reduction in fractures [17][18][19][20], while chemical dissolution may increase permeability [21]. The strong temperature dependence of precipitation/dissolution kinetics of minerals also exerts significance on permeability evolution [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Coupled Thermo-Hydro-Mechanical-Chemical Modeling of Permeability Evolution in a CO₂-Circulated Geothermal Reservoir

Tao

Elsworth

et al. 2019

Geofluids

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The meager availability of water as a heat transfer fluid is sometimes an impediment to enhanced geothermal system (EGS) development in semi-arid regions. One potential solution is in substituting CO2 as the working fluid in EGS. However, complex thermo-hydro-mechanical-chemical (THMC) interactions may result when CO2 is injected into the geothermal reservoir. We present a novel numerical model to describe the spatial THMC interactions and to better understand the process interactions that control the evolution of permeability and the heat transfer area. The permeability and porosity evolution accommodate changes driven by thermo-hydro-mechanical compaction/dilation and mineral precipitation/dissolution. Mechanical and hydraulic effects are demonstrated to exert a small and short-term influence on permeability change, while the thermal effects are manifest in the intermediate and short-term influence. The most significant and long-term influence on permeability change is by chemical effects, where decreases in fracture permeability may be of the order of 10-5 due to calcite precipitation in fracture throats, which causes the overall permeability to reduce to 70% of the initial permeability. The initial pressure and temperature of the injected CO2 exerts an overriding influence on permeability. In particular, an increased temperature reduces the mineral precipitation in the fracture and enhances mineral dissolution within the matrix and pore but results in mechanical closure of the fractures. Optimizing injection pressure and temperature may allow the minimization of precipitation and the maximization of heat recovery.

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“…However, the effect of chemical reaction on the hydraulic properties of the rock fractures and the spatial distribution of the fracture network is overlooked in these studies. For a better understanding of the performance of EGS, Ogata et al (2018) developed a multi-physics numerical model to predict the fluid flow and mass transport behavior of rock fractures under coupled THMC conditions. Through the comparison of experiment and simulation calculation, the developed model should be valid for evaluating the evolution in the fluid flow and mass transport behavior within rock fractures induced by mineral dissolution under stress and temperature controlled conditions.…”

Section: Introductionmentioning

confidence: 99%

Comparison of multi-field coupling numerical simulation in hot dry rock thermal exploitation of enhanced geothermal systems

Chen

Ding

Gong

et al. 2019

Adv. Geo-Energ. Res.

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In order to alleviate the environmental crisis and improve energy structure, countries from all over the world have focused on the hot dry rock geothermal resources with great potential and with little pollution. The geothermal heat production from enhanced geothermal system comes with complex multi-field coupling process, and it is of great significance to study the temporal and spatial evolution of geothermal reservoir. In this work, a practical numerical model is established to simulate the heat production process in EGS, and the comparison of thermal-hydraulic (TH), thermal-hydraulic-mechanical (THM) and thermal-hydraulic-mechanical-chemical (THMC) coupling in geothermal reservoir is analyzed. The results show that the stable production stage of the three cases is approximately 5 years; however, compared with TH and THMC coupling, the service-life for THM coupling decreased by 1140 days and 332 days, respectively. The mechanical enhanced effects are offset by the chemical precipitation, and the precipitation from SiO 2 is much larger than the dissolution of calcite.

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Modeling of coupled thermal-hydraulic-mechanical-chemical processes for predicting the evolution in permeability and reactive transport behavior within single rock fractures

Cited by 45 publications

References 48 publications

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Coupled Thermo-Hydro-Mechanical-Chemical Modeling of Permeability Evolution in a CO₂-Circulated Geothermal Reservoir

Comparison of multi-field coupling numerical simulation in hot dry rock thermal exploitation of enhanced geothermal systems

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Modeling of coupled thermal-hydraulic-mechanical-chemical processes for predicting the evolution in permeability and reactive transport behavior within single rock fractures

Cited by 45 publications

References 48 publications

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Fracture Sustainability in Enhanced Geothermal Systems: Experimental and Modeling Constraints

Coupled Thermo-Hydro-Mechanical-Chemical Modeling of Permeability Evolution in a CO2-Circulated Geothermal Reservoir

Comparison of multi-field coupling numerical simulation in hot dry rock thermal exploitation of enhanced geothermal systems

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Coupled Thermo-Hydro-Mechanical-Chemical Modeling of Permeability Evolution in a CO₂-Circulated Geothermal Reservoir