Moment-Frequency distribution as a constraint for hydro-mechanical modelling in fracture networks

International audienceShear re-activation of deep fractured rocks for EGS purposes is accompanied by microseismicity. From our numerical hydro-mechanical coupling in discrete fracture network models which incorporates stress drops with known amplitudes and neglects the influence of static stress changes, it happens that the moments of induced seismic events are scaling with the power 3 of the fracture size. It follows that the value of the slope of the moment-frequency diagram better known as the b'value obtained from numerical experiments correlates with the exponent of the power law distribution used for the fracture size generation. Our suggestion is therefore to use these diagrams for constraining the fracture network generation proces

Role of temperature change in micro seismic activity during fluid injections in faulted and fractured zones. Part 1 : Updating the thermal modelling in a DFN model using a double media approach

3International audienceL'exploitation de l'énergie géothermique des zones de socles ou de failles pour la production d'électricité fait l'objet de nombreux programmes de recherches en Europe en particulier (site de Soultz sous Forêts en France, Bâle en Suisse) avec la création de quelques sites pilotes opérationnels (Landau, Allemagne). Ces projets ont des caractéristiques communes, en particulier la nécessité d'améliorer les performances hydrauliques du réservoir, pour pouvoir atteindre une productivité économique, et aussi la nécessité de ré-injecter à basse température le fluide produit après passage dans les échangeurs de surfaces. Le succès de la première étape, optimisation du réservoir, dépend de la compréhension des interactions hydrauliques-mécaniques qui se développent pendant les phases de stimulation et (re-)fracturation du système naturel, et qui sont en partie contrôlées par le contexte tectonique local. Cette étape est cruciale. Des micro-seismes de trop fortes magnitudes ont été induits à Bâle et le projet est définitivement arrété. L'évolution à long terme du dispositif dépendra davantage du comportement thermique de la boucle géothermale. Nous savons que la présence de fluides dans les réseaux poreux des roches et la circulation des fluides à plus grande échelle (failles) contrôle le champ de température dans les premiers kilomètres de la croûte. Notre but est d'anticiper sur l'impact que pourrait avoir le refroidissement du à une circulation fluide imposée le long de fractures (convection forcée) dans le cadre d'une mise en exploitation géothermique d'une portion de faille avec re-injection froide. Le sujet consistera donc en une modélisation des échanges thermiques entre la roche et le fluide injecté afin de coupler l'évolution thermique du système au comportement hydro-mécanique du modèle, dans un contexte de faille normale (graben du Rhin), l'impact du refroidissement des roches allant dans le sens d'un accroissement des ouvertures des fractures. Ce point nous semble particulièrement à propos pour le cas du Rift d'Asal, (Djibouti), car le mécanisme naturel de propagation des failles sur ces sites pourrait bien être lié à l'écoulement naturel des fluides (C. Doubre et G. Peltzer, 2007) . Les fractures seraient donc en permanence dans un état de stabilité mécanique critique, et des ruptures potentiellement importantes pourraient être déclanchées. Ce mécanisme est à l'étude pour les micro séismes récents enregistrés sur le site des Geysers (Californie), et qui se localisent au centre du réservoir, exploité avec réinjection depuis plusieurs dizaines d'années. Dans l'approche proposée, on considérera le milieu remplissant les fractures comme étant poreux, ces fractures pouvant s'assembler à plus grande échelle en réseau, pour constituer un modèle de portion de faille. La matrice rocheuse sera imperméable dans un premier temps. Les outils numériques existant au laboratoire seront adaptés et améliorés pour cette application. - Dans les équations de Darcy (qui décrivent l'écoulement) on tiendra compte de la variation de densité et de viscosité du fluide provoquée par les différences de température, et le transport de chaleur sera convectif dans les fractures, conductif dans la matrice rocheuse. La convection pourra donc être mixte (naturelle et forcée). - Le comportement mécanique suppose que le milieu formant la matrice est élastique, et que les déformations sont des glissements le long des plans des fractures, lorsque un critère de rupture est atteint. Une première partie de ce travail consistera, à évaluer ce critère pour représenter l'état naturel avant toutes mise en circulation de fluides dans le réservoir. La perturbation thermique due à la circulation forcée d'un fluide sera alors superposée, et la question de la stabilité ré-évaluée pour différents temps. - Les données proviendront des bases partagées dans le cadre du projet européen GEISER support de la recherche sur la période 2010-2013, et pourront à titre prospectif être utilisées pour discuter d'un nouveau projet en cours d'implantation le long du rift d'Asal (Djibouti)

Influence of geological parameters on CO2 storage prediction in deep saline aquifer at industrial scale

International audienceConsequences of uncertainties on geological parameters are examined using 2D models at large extension. Reduction of the uncertainties on predictions is also investigated, either because parameter's influence is negligible for the project design, or by showing for which parameters additional data will significantly increase the quality of prediction. TOUGH2/ECO2N is used to simulate the injection of millions tonnes of CO2 for the specific case of the Dogger aquifer (carbonates aquifer in the Paris Basin) with high lateral and vertical heterogeneities and for which few data are available. Studied parameters are spatial variability and correlation length of permeability, value of absolute permeability, pore compressibility, caprock permeability and relative permeability curves. Several numerical models of permeability are constructed: two uniform cases (two values of permeability) and 200 geostatistical initial realizations, which are modified according to the studied parameters. Results are compared in terms of propagation of pressure perturbations, injectivity (pressure in the vicinity of the well) and in terms of gas migration and dissolution. The results indicate, for the specific scale and values, that: (1) Pore compressibility, absolute value and spatial variability of permeability have the main influence on pressure propagation and injectivity. Relative permeability curves and correlation lengths have a weaker influence for the peak of pressure but tend to increase the variations for maximum/minimum cases. (2) Relative permeability curves and heterogeneities have a significant impact on prediction of gas dissolution and migration. At last, we also investigate the possibility to reduce the number of runs

Can we import quality tools? a feasibility study of European practice assessment in a country with less organised general practice

<p>Abstract</p> <p>Background</p> <p>Quality is on the agenda of European general practice (GP). European researchers have, in collaboration, developed tools to assess quality of GPs. In this feasibility study, we tested the European Practice Assessment (EPA) in a one-off project in Belgium, where general practice has a low level of GP organisation.</p> <p>Methods</p> <p>A framework for feasibility analysis included describing the recruiting of participants, a brief telephone study survey among non-responders, organisational and logistic problems. Using field notes and focus groups, we studied the participants' opinions.</p> <p>Results</p> <p>In this study, only 36 of 1000 invited practices agreed to participate. Co-ordination, administrative work, practice visits and organisational problems required several days per practice. The researchers further encountered technical problems, for instance when entering the data and uploading to the web-based server. In subsequent qualitative analysis using two focus groups, most participant GPs expressed a positive feeling after the EPA procedure. In the short period of follow-up, only a few GPs reported improvements after the visit. The participant GPs suggested that follow-up and coaching would probably facilitate the implementation of changes.</p> <p>Conclusion</p> <p>This feasibility study shows that prior interest in EPA is low in the GP community. We encountered a number of logistic and organisational problems. It proved attractive to participants, but it can be augmented by coaching of participants in more than a one-off project to identify and achieve targets for quality improvement. In the absence of commitment of the government, a network of universities and one scientific organisation will offer EPA as a service to training practices.</p

The Ratio 1660/1690 cm−1 Measured by Infrared Microspectroscopy Is Not Specific of Enzymatic Collagen Cross-Links in Bone Tissue

In postmenopausal osteoporosis, an impairment in enzymatic cross-links (ECL) occurs, leading in part to a decline in bone biomechanical properties. Biochemical methods by high performance liquid chromatography (HPLC) are currently used to measure ECL. Another method has been proposed, by Fourier Transform InfraRed Imaging (FTIRI), to measure a mature PYD/immature DHLNL cross-links ratio, using the 1660/1690 cm−1 area ratio in the amide I band. However, in bone, the amide I band composition is complex (collagens, non-collagenous proteins, water vibrations) and the 1660/1690 cm−1 by FTIRI has never been directly correlated with the PYD/DHLNL by HPLC. A study design using lathyritic rats, characterized by a decrease in the formation of ECL due to the inhibition of lysyl oxidase, was used in order to determine the evolution of 1660/1690 cm−1 by FTIR Microspectroscopy in bone tissue and compare to the ECL quantified by HPLC. The actual amount of ECL was quantified by HPLC on cortical bone from control and lathyritic rats. The lathyritic group exhibited a decrease of 78% of pyridinoline content compared to the control group. The 1660/1690 cm−1 area ratio was increased within center bone compared to inner bone, and this was also correlated with an increase in both mineral maturity and mineralization index. However, no difference in the 1660/1690 cm−1 ratio was found between control and lathyritic rats. Those results were confirmed by principal component analysis performed on multispectral infrared images. In bovine bone, in which PYD was physically destructed by UV-photolysis, the PYD/DHLNL (measured by HPLC) was strongly decreased, whereas the 1660/1690 cm−1 was unmodified. In conclusion, the 1660/1690 cm−1 is not related to the PYD/DHLNL ratio, but increased with age of bone mineral, suggesting that a modification of this ratio could be mainly due to a modification of the collagen secondary structure related to the mineralization process

Fifteen years of research on oral–facial–digital syndromes: from 1 to 16 causal genes

Oral–facial–digital syndromes (OFDS) gather rare genetic disorders characterised by facial, oral and digital abnormalities associated with a wide range of additional features (polycystic kidney disease, cerebral malformations and several others) to delineate a growing list of OFDS subtypes. The most frequent, OFD type I, is caused by a heterozygous mutation in the OFD1 gene encoding a centrosomal protein. The wide clinical heterogeneity of OFDS suggests the involvement of other ciliary genes. For 15 years, we have aimed to identify the molecular bases of OFDS. This effort has been greatly helped by the recent development of whole-exome sequencing (WES). Here, we present all our published and unpublished results for WES in 24 cases with OFDS. We identified causal variants in five new genes (C2CD3, TMEM107, INTU, KIAA0753 and IFT57) and related the clinical spectrum of four genes in other ciliopathies (C5orf42, TMEM138, TMEM231 and WDPCP) to OFDS. Mutations were also detected in two genes previously implicated in OFDS. Functional studies revealed the involvement of centriole elongation, transition zone and intraflagellar transport defects in OFDS, thus characterising three ciliary protein modules: the complex KIAA0753-FOPNL-OFD1, a regulator of centriole elongation; the Meckel-Gruber syndrome module, a major component of the transition zone; and the CPLANE complex necessary for IFT-A assembly. OFDS now appear to be a distinct subgroup of ciliopathies with wide heterogeneity, which makes the initial classification obsolete. A clinical classification restricted to the three frequent/well-delineated subtypes could be proposed, and for patients who do not fit one of these three main subtypes, a further classification could be based on the genotype

A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing

Purpose Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the “ClinVar low-hanging fruit” reanalysis, reasons for the failure of previous analyses, and lessons learned. Methods Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. Results We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). Conclusion The “ClinVar low-hanging fruit” analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock

Expertise hydrogéologique et impact environnemental dus ite du crassier de Marthod (Ugitech, 73)

21 p.Le site industriel métallurgique d'Ugine (73) comprend des espaces de stockage internes de type 'crassier' où sont stockés temporairement des laitiers d'aciéries, avant réutilisation comme matériaux de remblais. Ces résidus, très compact à la base des amas, restent soumis à l'action des eaux météoriques et produisent des lixiviats qui peuvent s'infiltrer dans le sol et entrer en contact avec les eaux de l'aquifère sous jacent (système alluvial de la rivière Arly)

An attempt to generate physically-based DFN for coupled hydro-mechanical simulation

Session 1-Advances in Discrete Fracture Network (DFN) models, abstract 55International audienc