The Effects of Regional Fluid Flow on Deep Temperatures (Hesse, Germany)

Koltzer, Nora; Scheck‐Wenderoth, Magdalena; Sippel, Judith; Cacace, Mauro; Frick, Maximilian; Sass, Ingo; Fritsche, Johann-Gerhard; Bär, Kristian

doi:10.3390/en12112081

Cited by 14 publications

(6 citation statements)

References 38 publications

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“…As shown in Figure 7, the general graph of stress-strain curves was obtained on the basis of multiple sets of compressive tests. The overall law of the curve change was basically the same, and similar results can be found in existing studies [27,28]. The development of curves show that the compression stress first rose rapidly to the peak value, then turning into a falling section and decaying thus to the residual strength.…”

Section: Fracture Failure Processsupporting

confidence: 86%

“…All changes in environmental factors were performed by a servo control system of the curing apparatus. According to our previous field test results and investigations on some typical high-geothermal tunnels, the grouting material specimens were tested at different combination of temperature (40 • C, 60 • C, 80 • C) and relative humidity (25%, 55%, 95%) [25][26][27]. Moreover, the compressive strength of grouting specimens cured at 3 days and 28 days were selected as the main study subjects.…”

Section: Curing Methods For Samplesmentioning

confidence: 99%

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Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Wang

Jiang

et al. 2020

Materials

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The cement-based grouting materials used for practical purposes in high-geothermal tunnels are inevitably affected by humidity and high temperature, leading to the deterioration of mechanical properties. Based on the characteristics of changing high temperatures and two typical conditions of hot-humid and hot-dry environments in high-geothermal tunnels, many mechanical strength tests were carried out on the grouting material cured under different environmental conditions. The study results indicated that high temperature and low relative humidity were unfavorable to the development of mechanical characteristics of grouting material, but the coupling effect of two factors could improve the strength at early ages and reduce the degradation of long-term strength. As the curing temperature exceeded 56.3 °C, the humidity effect on strength played a more important role in recovering the strength of grouting material damaged by high temperature. Temperature had more significant impact on the relative peak stress while the relative humidity had greater influence on the relative peak strain. A calculation compressive constitutive model was prospered, which considering both temperature and relative humidity. The study results may provide much valuable experimental data and theoretical supporting for the design of compression constitutive of cement-based grouting material in high-geothermal tunnel.

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Section: Fracture Failure Processsupporting

confidence: 86%

Section: Curing Methods For Samplesmentioning

confidence: 99%

Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Wang

Jiang

et al. 2020

Materials

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“…In literature, this can often be observed indirectly. For example, in geothermal applications basin-scale applications usually consider a hydrothermal system, whereas reservoir-scale applications also incorporate the mechanical and/or the chemical processes (e.g., Freymark et al, 2019;Gelet et al, 2012;Cacace, 2017, 2020b, a;Kohl et al, 1995;Kolditz et al, 2012;Koltzer et al, 2019;O'Sullivan et al, 2001;Poulet et al, 2014;Stefansson et al, 2020;Vallier et al, 2018;Wellmann and Reid, 2014). Another example is magnetotellurics (MT).…”

Section: Physics-based Surrogate Modeling / Model Order Reductionmentioning

confidence: 99%

Perspectives of Physics-Based Machine Learning for Geoscientific Applications Governed by Partial Differential Equations

Degen

Caviedes‐Voullième²,

Buiter

et al. 2023

Preprint

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Abstract. An accurate assessment of the physical states of the Earth system is an essential component of many scientific, societal and economical considerations. These assessments are becoming an increasingly challenging computational task since we aim to resolve models with high resolutions in space and time, to consider complex coupled partial differential equations, and to estimate uncertainties, which often requires many realizations. Machine learning methods are becoming a very popular method for the construction of surrogate 5 models to address these computational issues. However, they also face major challenges in producing explainable, scalable, interpretable and robust models. In this manuscript, we evaluate the perspectives of geoscience applications of physics-based machine learning, which combines physics-based and data-driven methods to overcome the limitations of each approach taken alone. Through three designated examples (from the fields of geothermal energy, geodynamics, and hydrology), we show that the non-intrusive reduced basis method as a physics-based machine learning approach is able to 10 produce highly precise surrogate models that are explainable, scalable, interpretable, and robust.

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“…Hence, the understanding of various petrophysical correlations can be improved by this cost-effective digital approach. Quantifying the impact of different pore-scale processes on hydraulic and mechanical reservoir properties is of particular importance for numerous applications related to geological subsurface utilisation, including geothermal systems [69,70], energy storage [71,72], hydrocarbon reservoirs [73,74], nuclear waste disposal [75,76] or groundwater resources [77,78].…”

Section: Advantages and Opportunities Of Synthetic Sandstonesmentioning

confidence: 99%

Diagenetic Trends of Synthetic Reservoir Sandstone Properties Assessed by Digital Rock Physics

2021

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Quantifying interactions and dependencies among geometric, hydraulic and mechanical properties of reservoir sandstones is of particular importance for the exploration and utilisation of the geological subsurface and can be assessed by synthetic sandstones comprising the microstructural complexity of natural rocks. In the present study, three highly resolved samples of the Fontainebleau, Berea and Bentheim sandstones are generated by means of a process-based approach, which combines the gravity-driven deposition of irregularly shaped grains and their diagenetic cementation by three different schemes. The resulting evolution in porosity, permeability and rock stiffness is examined and compared to the respective micro-computer tomographic (micro-CT) scans. The grain contact-preferential scheme implies a progressive clogging of small throats and consequently produces considerably less connected and stiffer samples than the two other schemes. By contrast, uniform quartz overgrowth continuously alters the pore space and leads to the lowest elastic properties. The proposed stress-dependent cementation scheme combines both approaches of contact-cement and quartz overgrowth, resulting in granulometric, hydraulic and elastic properties equivalent to those of the respective micro-CT scans, where bulk moduli slightly deviate by 0.8%, 4.9% and 2.5% for the Fontainebleau, Berea and Bentheim sandstone, respectively. The synthetic samples can be further altered to examine the impact of mineral dissolution or precipitation as well as fracturing on various petrophysical correlations, which is of particular relevance for numerous aspects of a sustainable subsurface utilisation.

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The Effects of Regional Fluid Flow on Deep Temperatures (Hesse, Germany)

Cited by 14 publications

References 38 publications

Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Perspectives of Physics-Based Machine Learning for Geoscientific Applications Governed by Partial Differential Equations

Diagenetic Trends of Synthetic Reservoir Sandstone Properties Assessed by Digital Rock Physics

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