3D seismic for design and derisking of dual geothermal boreholes in sedimentary sequences and new prospects in the Paris Basin (Adapted methodology using petroleum industry techniques)

International audienceThe use of existing geological and structural maps, previous 2D seismic profiles, boreholes and correlation models between these data is sufficient to understand basin structure and thermal systems on a regional scale. However, this is not sufficient on a scale of a geothermal site to be sure of the hydraulic connectivity (or of the presence of a permeability barrier) between two boreholes 1.5 or 2 km apart.To ensure that there is enough hydraulic connectivity, it i s necessary to understand the controls on the network of fractures which affects the aquifer (fracture permeability) and the physical properties of the rock, namely the porosity and clay content in order to obtain a matrix permeability.The latest generation of broadband (six octaves) 3D seismic reflection will provide the following information: the similarity attribute will give an accurate structural map of the fault network at the seismic resolution and, in many cases, at a higher resolution than seismic; seismic velocity anisotropy analysis techniques will make it possible to visualize a 3D volume of information on the fracture network [Michel et al. (2013) Application of Azimuthal Seismic Inversion for Shale Gas Reservoir – Proceedings of the 11th SEGJ International Symposium, Yokohama]; acoustic impedance inversion or petrophysical inversion techniques will predict the porosity throughout the whole volume of the aquifer from a porosity log recorded in a pilot-hole. It allows a real 3D mapping of predicted porosity inside the aquifer much more reliably than from modelling alone.These seismic techniques were initially developed for petroleum exploration and development. They have rapidly progressed throughout the last decade, both in acquisition, processing and interpretation with new methodologies and high-performance softwares. They are efficient for modelling reservoirs to be produced.And, consequently, they can be used for geothermal applications as data to design dual deviated drillings with horizontal drains in carbonate and clastic reservoirs – not only for new projects, but also to revisit old ones to improve their performance or develop another reservoir.Broadband 3D seismic will secure the exploration of Triassic sandstones which stay an interesting prospect for deep geothermal projects.New prospects are proposed in the Paris Basin: Regional faults overlap the substratum. Inside faulted zones, hydrothermal circulations arriving by convection at the top of granitic basement could be geothermal objectives, as in the Alsace Upper Rhine Graben.A production pilot site is suggested to test superimposed aquifers and a regional fault and, at the same time, two different architectures of boreholes doublets: horizontal drains for aquifers and deviated wells for crossing a regional fault.The first site that will use this approach could be instrumented and used as an experiment with a small addition of measurements and sensors, thus becoming a showcase for geothermal energy in France. The objective of this experiment would be to determine the transit time, the heating time of the re-injected water and the circulation speed to define the optimal direction, spacing and length of drains, and also, to realize the thermal modelling of the site for different options

Mechanical activation conditions of the Fe2O3 and V2O3 mixture powders in order to obtain a nanometric vanadium spinel ferrite

International audienc

Infrared & Visible Ultrastable Optical Frequency Standard

International audienceWe report on the development of a three-wavelength optical frequency standard (OFS: ?, 2?, 3?), frequency stabilized to a narrow iodine hyperfine line around 514 nm. To bridge the frequency gap between the infrared and the green ranges of the optical domain (1542 nm ? 514 nm), we use an efficient third harmonic generation process, based on two cascaded Lithium Niobate crystals, arranged in an original optical configuration. Up to 300 mW of green power is obtained from 800 mW of IR power, corresponding to an unprecedented demonstration of an optical conversion efficiency ? = P3?/P? 36 \% in continuous wave regime. Iodine Doppler-free spectroscopy technique is used to frequency stabilize this OFS against a narrow hyperfine line at 514 nm yielding to a frequency stability ?y(?)=2.8 × 10-14 ?-1/2, with a minimum value of 7.3 × 10-15 after 200 s of integration time

Linear {Zeeman} {Effect} on {Iodine}-{Based} {Frequency} {Stabilized} {Laser}

International audienceWe report on the effect of a weak external magnetic field on iodine hyperfine transitions around 514 nm, used for infrared laser frequency stabilization. We use a frequency tripled laser diode operating at 1542.1 nm, to interrogate the iodine vapor inserted into a short sealed quartz cell, surrounded by an efficient solenoid. Thus we create a controlled external magnetic fields whose orientation is longitudinal to the counter-propagating laser beams direction with a level of 7 Gauss/Ampere. The combination of the iodine cell and the solenoid is inserted into a magnetic shield that ensures a residual magnetic field with an attenuation factor of 200. We have observed a linear Zeeman Effect that affects the iodine hyperfine line width as well as its center frequency. We measured large frequency shifts, induced by the longitudinal magnetic field, at the level of 1.8×10-12/Gauss, for all 15 hyperfine components of the R 34[44-0]127 I2 line at 514.017 nm. Thus an isolation from external magnetic fields below the mG level is required to confer a residual frequency instability at the 10-15 level

Circular Economy Applied to Organic Residues and Wastewater: Research Challenges

International audienceTo move today’s agricultural and urban systems towards tomorrow’s circular economy and respond to climate change, it is imperative to turn organic residues and wastewater into resourceful assets. This article discusses the changes that are needed in research to drive this paradigm shift and to go from a “losses and waste” situation to a “resource and opportunities” ambition. The current lines of research aim to maximise the use and value of biomass or organic residues and wastewater and propose new organisational schemes driven by technical innovations. Exploring the pathways to a sustainable future through many domains let us identify five challenges to structure the research efforts and find circular bioeconomy solutions for organic residues and wastewater: (1) proposing innovative processes and integrated multi-process systems; (2) promoting the emergence of multi-scale and cross-sectoral organisations; (3) developing multi-performance evaluation methods, (4) rethinking research–society intersections, and (5) enhancing research–legislation interactions. We end by outlining prospects for moving forward past current limitations: beyond increasing knowledge, research will continue its own transition. Our responsibility today is not to think about what we could do for a better world but what we should do to make our ever-changing world even better and more sustainable

Amplification of R-spondin1 signaling induces granulosa cell fate defects and cancers in mouse adult ovary

R-spondin1 is a secreted regulator of WNT signaling, involved in both embryonic development and homeostasis of adult organs. It can have a dual role, acting either as a mitogen or as a tumor suppressor. During ovarian development, Rspo1 is a key factor required for sex determination and differentiation of the follicular cell progenitors, but is downregulated after birth. In human, increased RSPO1 expression is associated with ovarian carcinomas, but it is not clear whether it is a cause or a consequence of the tumorigenic process. To address the role of Rspo1 expression in adult ovaries, we generated an Rspo1 gain-of-function mouse model. Females were hypofertile and exhibited various ovarian defects, ranging from cysts to ovarian tumors. Detailed phenotypical characterization showed anomalies in the ovulation process. Although follicles responded to initial follicle-stimulating hormone stimulation and developed normally until the pre-ovulatory stage, they did not progress any further. Although non-ovulated oocytes degenerated, the surrounding follicular cells did not begin atresia. RSPO1-induced expression not only promotes canonical WNT signaling but also alters granulosa cell fate decisions by maintaining epithelial-like traits in these cells. This prevents follicle cells from undergoing apoptosis, leading to the accumulation of granulosa cell tumors that reactivates the epithelial program from their progenitors. Taken together, our data demonstrate that activation of RSPO1 is sufficient in promoting ovarian tumors and thus supports a direct involvement of this gene in the commencement of ovarian cancers

Obstetric Perspectives: Consensus of the Gynecology Department of the University of Liege. Document of the 3rd Cycle Studies, October 96

peer reviewe

Interroger et comprendre les effets d’échelles de la vulnérabilité

Responsables du numéro : Valérie Morel, Sylvie Coupleu