Sensitivity analysis of deep geothermal reservoir: Effect of reservoir parameters on production temperature

Knowledge of temperature at drillable depth is a prerequisite in site selection for geothermal exploration and development of enhanced geothermal systems (EGS). Equally important, the thermo-mechanical signature of the lithosphere and crust provides critical constraints for the crustal stress field and basement temperatures where borehole observations are rare. The stress and temperature field in Europe is subject to strong spatial variations often linked to polyphase extensional and compressional reactivation of the lithosphere, in different modes of deformation. The development of innovative combinations of numerical and analogue modelling techniques is key to thoroughly understand the spatial and temporal variations in crustal stress and temperature. In this paper we present an overview of advances in developing and applying analogue and numerical thermo-mechanical models to quantitatively assess the interplay of lithosphere dynamics and basin (de)formation. Field studies of kinematic indicators and numerical modelling of present-day and paleo-stress fields in selected areas yield new constraints on the causes and the expression of intraplate stress fields in the lithosphere, driving basin (de)formation. The actual basin response to intraplate stress is strongly affected by the rheological structure of the underlying lithosphere, the basin geometry, fault dynamics and interplay with surface processes. Integrated basin studies show that the rheological structure of the lithosphere plays an important role in the spatial and temporal distribution of stress-induced vertical motions, varying from subtle faulting to basin reactivation and large wavelength patterns of lithospheric folding. These findings demonstrate that sedimentary basins are sensitive recorders of the intraplate stress field. The long lasting memory of the lithosphere, in terms of lithospheric scale weak zones, plays a far more important role in basin formation and reactivation than hitherto assumed. A better understanding of the 3-D linkage between basin formation and basin reactivation is, therefore, an essential step in connecting lithospheric forcing and upper mantle dynamics to crustal vertical motions and stress, and their effect on sedimentary systems and heat flow. Vertical motions in basins can become strongly enhanced, through coupled processes of surface erosion/sedimentation and lower crustal flow. Furthermore, patterns of active thermal attenuation by mantle plumes can cause a significant spatial and modal redistribution of intraplate deformation and stress, as a result of changing patterns in lithospheric strength and rheological layering. The models provide useful constraints for geothermal exploration and production, including understanding and predicting crustal stress and basin and basement heat flow. © 2010 Elsevier B.V.

Lithosphere tectonics and thermo-mechanical properties: An integrated modeling approach for enhanced geothermal systems exploration in Europe

The European Cenozoic Rift System hosts major temperature anomalies in Central Europe. In its central segment, the Upper Rhine Graben (URG), temperatures range from 75°C to nearly 150°C at a depth of 2000 m. Different hypotheses have been suggested to explain the localization of these anomalies. Our review and comprehensive interpretation of gravimetric and magnetic data, as well as neotectonic activity patterns, suggests that low-density, mostly magnetic and fractured granitic basement is systematically associated with major temperature anomalies. Further analyses provide insight into different heat transport processes contributing to the localization of these anomalies. Magnetic and gravity anomalies are known to represent lithological variations associated with the pre-Permian. We show their spatial relationship with positive temperature anomalies in the URG. Correlation between magnetics and temperature reveal a mean contribution of heat production to the temperature anomaly of about 10–15°C. A slight...

Localization of temperature anomalies in the Upper Rhine Graben: insights from geophysics and neotectonic activity

https://publikationen.bibliothek.kit.edu/1000071274/66997130

Hydraulic performance history at the Soultz EGS reservoirs from stimulation and long-term circulation tests

Geothermal projects in the Upper Rhine Graben aim to harness thermal anomalies that have arisen due to hydrothermal circulation within the granitic basement and the overlying Permo-Triassic sedimentary units. We present here a systematic microstructural, mineralogical, and petrophysical characterisation of the lowermost unit of this Permo-Triassic sedimentary succession—the Buntsandstein—sampled from exploration well EPS-1 at the Soultz-sous-Forets geothermal site (France). Twelve depths were sampled (from 1008 to 1414 m) and cylindrical cores were prepared perpendicular and parallel to bedding. These cores were described in terms of their microstructure, grain size and shape, specific surface area, pore size and pore throat size distribution, mineral content, porosity, P-wave velocity, and permeability. The Buntsandstein sandstones are predominantly feldspathic sandstones, often characterised by pores filled or partially filled (with clays (R3 illite–smectite), dolomite, siderite, and barite) as a consequence of diagenesis, tectonics, and the circulation of hydrothermal fluids. The porosity, dry P-wave velocity, and permeability of these sandstones vary from ~ 0.03 to 0.2, ~ 2.5 to 4.5 km s−1, and ~ 10−18 to 10−13 m2, respectively. Our data show that P-wave velocity decreases and permeability increases as porosity increases. P-wave velocities are significantly higher when measured parallel to bedding (by about 10 to 25%), and that saturation with water increases P-wave velocity (by about 5 to 50%, depending on sample orientation). The pervasive pore-filling precipitation has significantly reduced the permeabilities of the Buntsandstein sandstones, which are orders of magnitude less permeable than similarly porous unaltered sandstone. We also find that their permeability can be up to an order of magnitude more permeable when measured parallel to bedding than perpendicular to bedding. Although Buntsandstein units with low matrix permeabilities (as low as ~ 10−18 m2) require macroscopic fractures to attain the high permeability required to sustain regional hydrothermal circulation, matrix permeability is important for units with low fracture densities and high matrix permeabilities. We anticipate that these data will aid future fluid flow modelling and seismic investigations at geothermal sites within the Upper Rhine Graben.

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Microstructural and petrophysical properties of the Permo-Triassic sandstones (Buntsandstein) from the Soultz-sous-Forêts geothermal site (France)

https://hal-brgm.archives-ouvertes.fr/hal-00801798/document

Structure of hydrothermal convection in the Upper Rhine Graben as inferred from corrected temperature data and basin-scale numerical models

Protein is biology workhorse. Since the recent break-through of novel folding methods, the amount of available structural data is increasing, closing the gap between data-driven sequence-based and structure-based methods. In this work, we focus on the inverse folding problem that consists in predicting an amino-acid primary sequence from protein 3D structure. For this purpose, we introduce a simple Transformer model from Natural Language Processing augmented 3D-structural data. We call the resulting model PeTriBERT: Proteins embedded in tridimensional representation in a BERT model. We train this small 40-million parameters model on more than 350 000 proteins sequences retrieved from the newly available AlphaFoldDB database. Using PetriBert, we are able to in silico generate totally new proteins with a GFP-like structure. These 9 of 10 of these GFP structural homologues have no ressemblance when blasted on the whole entry proteome database. This shows that PetriBert indeed capture protein folding rules and become a valuable tool for de novo protein design.

/pdf/petribert-augmenting-bert-with-tridimensional-encoding-for-3avyy10p.pdf

PeTriBERT : Augmenting BERT with tridimensional encoding for inverse protein folding and design

The first Genome Wide Association Studies (GWAS) shed light on the concept of missing heritability. It constitutes a mystery with transcending consequences from plant to human genetics. This mystery lies in the fact that a large proportion of phenotypes are not explained by unique or simple genomic modifications. One has to invoke genetic interactions among different loci, also known as epistasis, to partly account for it. However, current GWAS statistical models are moderately scalable, very sensitive to False Discovery Rate (FDR) corrections and, even combined with High Performance Computing (HPC), they can take years to evaluate for a full combinatorial epistatic space for a single phenotype. Here we propose a modeling approach, named Next-Gen GWAS (NGG) that evaluates, within hours, >60 billions of single nucleotide polymorphism (SNP) combinatorial first-order interactions, on a reasonable computer power. We first benchmark NGG on state of the art GWAS model results, and applied this to Arabidopsis thaliana providing 2D epistatic maps at gene resolution. We demonstrate on several phenotypes that a large proportion of the missing heritability can i) be retrieved with this modeling approach, ii) indeed lies in epistatic interactions and iii) can be used to improve phenotype prediction.

Clément Carrė

Papers

Structure of hydrothermal convection in the Upper Rhine Graben as inferred from corrected temperature data and basin-scale numerical models

PeTriBERT : Augmenting BERT with tridimensional encoding for inverse protein folding and design

Full epistatic interaction maps retrieve part of missing heritability and improve phenotypic prediction