Modeling heat transport processes in enhanced geothermal systems: A validation study from EGS Collab Experiment 1

Wu, Hui; Fu, Pengcheng; Frone, Zachary; White, Mark D.; Ajo‐Franklin, Jonathan; Morris, Joseph P.; Knox, H. A.; Schwering, Paul; Strickland, Christopher E.; Roberts, Benjamin Q.; Vermeul, Vince R.; Mattson, Earl D.; Ingraham, Mathew Duffy; Kneafsey, Timothy J.; Blankenship, Douglas A.

doi:10.1016/j.geothermics.2021.102254

Cited by 15 publications

(7 citation statements)

References 27 publications

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“…Notice that the two residuals 𝑹 solid and 𝑹 fluid are provided in Equations ( 6) and (7) in the component forms. The first task is to linearize the residual of the solid problem.…”

Section: Consistent Linearization and Initializationmentioning

confidence: 99%

“…Many geological processes and geotechnical engineering applications can be modeled as fracture propagation in porous media that are driven by pressurized fluid. Developing robust numerical methods to accurately simulate these processes can provide better understandings about many natural phenomena, such as magmatic system, 1,2 and improve existing engineering techniques, such as hydraulic fracturing 3–6 and geothermal energy harvesting 7 . The fracture propagation in geological systems driven by injected fluid involves two different physical processes.…”

Section: Introductionmentioning

confidence: 99%

“…Developing robust numerical methods to accurately simulate these processes can provide better understandings about many natural phenomena, such as magmatic system, 1,2 and improve existing engineering techniques, such as hydraulic fracturing [3][4][5][6] and geothermal energy harvesting. 7 The fracture propagation in geological systems driven by injected fluid involves two different physical processes. On the one hand, the porous media deforms under the pressure induced by the injected fluid, and cracks are initialized due to stress concentration and material inhomogeneity and then further propagate following complex paths.…”

Section: Introductionmentioning

confidence: 99%

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A consistent linearization scheme for KGD problems using fracture tip asymptotic solutions

Jin

2023

Num Anal Meth Geomechanics

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Recently, a fluid volume enrichment strategy based on the asymptotic solutions near the crack tip was proposed for fluid‐driven fracture propagation problems. Despite its successes in various benchmark and field‐scale problems of hydraulic fracturing simulations, the aforementioned enrichment strategy has the following limitations. First, the tightly coupled solid‐fluid nonlinear system cannot be consistently linearized due to the fast marching method applied to solve the Eikonal equation for fracture tracking. As a result, an approximated Jacobian had to be deployed for the Newton‐Raphson iterations. This is particularly troublesome when the fracture front propagates into newly fractured cells, since a large number of nonlinear iterations are required for convergence because of the inconsistent linearization. Second, the existing method only focused on the viscosity‐dominated fracture propagation regime. Even though the extension of the method to the toughness‐dominated regime could be relatively straightforward, it is not immediately clear how to apply the enrichment technique to the transition regime. This work is dedicated to address the above two limitations. Specifically, a unified fracture propagation criterion is proposed, which not only works for the viscosity‐dominated regime, but also for the toughness‐dominated regime and the transition regime in between. The techniques to consistently linearize the coupled solid‐fluid system and properly initialize the primary unknowns are demonstrated, which result in the significant reduction of required number of nonlinear iterations for convergence. The proposed technique is demonstrated in the context of the Khristianovic‐Geertsma‐de Klerk (KGD) problems due to its relative simplicity.

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“…Notice that the two residuals 𝑹 solid and 𝑹 fluid are provided in Equations ( 6) and (7) in the component forms. The first task is to linearize the residual of the solid problem.…”

Section: Consistent Linearization and Initializationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A consistent linearization scheme for KGD problems using fracture tip asymptotic solutions

Jin

2023

Num Anal Meth Geomechanics

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“…In many geological processes and engineering applications, fracture propagation in solid media is driven by the internal pressurization due to injected viscous fluid. Numerical strategies to robustly and accurately simulate fluid-driven fracture propagation have significance in advancing the scientific understanding of various natural phenomena in geoscience, such as magmatic hydrothermal system 1,2 as well as dike and sill formation, 3,4 and disrupting the status quo of geological techniques, such as hydraulic fracturing, [5][6][7] geothermal energy harvesting, [8][9][10] dam safety evaluation, [11][12][13] and contaminated soil remediation. 14,15 From the perspective of numerical simulations, developing a robust and accurate numerical strategy to model the fluid-driven fracture propagation faces the following challenges:…”

Section: Introductionmentioning

confidence: 99%

A robust finite element‐finite volume strategy for viscosity‐dominated hydraulic fracture propagation using an asymptotic tip enrichment

Jin

White

Settgast

2022

Num Anal Meth Geomechanics

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Fluid‐driven fracture propagation is widely observed in various geological processes and crucial to many applications of geological engineering. Developing robust and accurate numerical strategies has significance in advancing the scientific understanding and engineering applications related with fluid‐driven fracture propagation. We present a finite element‐finite volume strategy using asymptotic fracture tip enrichment to model the fluid‐driven fracture propagation in three‐dimensional Cartesian meshes under the viscosity‐dominated regime, in which the fluid viscosity‐related process is the dominant energy dissipation mechanism. We use the finite element method to discretize the balance of linear momentum equation for the deformed solid and the finite volume method to discretize the Reynolds equation that governs the fluid flow. In order to track the evolving fracture front in heterogeneous media, we extend the implicit level set approach originally proposed for the displacement discontinuity method. Through this process, a signed distance‐based fracture propagation criterion naturally emerges and is suitable for the viscosity‐dominated regime when solid toughness becomes irrelevant. Critically, we enrich the fluid volume treatment near the fracture front using the tip asymptotic solution. This enrichment strategy is crucial to overcome the mesh nonconformity caused by the arbitrary intersections between propagating fracture front and underlying Cartesian meshes. We compare the numerical results with analytical solutions of the KGD problem and the penny‐shape problem, and illustrate the mesh size and time step‐insensitivity of the numerical results due to the tip enrichment technique. Also, we demonstrate the capabilities of the proposed method to model fluid‐driven fracture propagation in various heterogeneous media.

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“…At present, the numerical simulation method has been widely used because of its economical and fast characteristics, which can efficiently simulate and analyze the coupling process of EGS heat transfer. Based on field experiments, Wu et al [12] established a high-simulation three-dimensional EGS numerical model to simulate the key heat transfer processes related to EGS heat extraction and studied the effect of different heat transfer mechanisms such as heat convection of fracture flow and heat conduction of rock layer on the effect of EGS heat extraction performance.…”

Section: Introductionmentioning

confidence: 99%

Influence Factors on EGS Geothermal Reservoir Extraction Performance

Wang

Cheng

2022

Geofluids

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The heat extraction performance of the enhanced geothermal system is simulated by using COMSOL software. The effects of six factors, such as the thermal conductivity of heat reservoir, matrix permeability, fracture width, injection temperature, injection flow rate, and the number of wells, on the heat extraction performance of EGS heat reservoir for 40 years are analyzed. The results show that the matrix permeability and injection flow are the main factors affecting the heat production performance of the EGS geothermal reservoir, while the thermal conductivity, fracture width, and injection temperature have little effect on the heat production performance of the EGS geothermal reservoir. Although increasing the number of production wells can improve the uneven distribution of the flow field to improve the system heat performance, taking into account the existing drilling technology and cost, the cost is higher, and the two-well system is still the basic form of absorbing rock heat.

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Modeling heat transport processes in enhanced geothermal systems: A validation study from EGS Collab Experiment 1

Abstract: Analyzed heat transport processes in an intermediate-scale EGS field experiment.• Developed a high-fidelity model incorporating a well-constrained fracture network.

Cited by 15 publications

References 27 publications

A consistent linearization scheme for KGD problems using fracture tip asymptotic solutions

A consistent linearization scheme for KGD problems using fracture tip asymptotic solutions

A robust finite element‐finite volume strategy for viscosity‐dominated hydraulic fracture propagation using an asymptotic tip enrichment

Influence Factors on EGS Geothermal Reservoir Extraction Performance

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