Constrained nonlinear optimization for extreme scenarii evaluation in reservoir characterization.

International audienceThe goal of reservoir characterization is the estimation of unknown reservoir parameters (the history matching problem), by integrating available data in order to take decisions for production scheme and to predict the oil production of the field in the future (the forecast problem). The reservoir parameters could be classified in two classes: • those related to the geological modeling (spatial distribution of porosity, permeability, faults), • and those related to the fluid flow modeling (relative permeability curves, productivity index of the wells). Those parameters could not be directly determined by measurements (or only locally using well logs), this is the reason why this parameter estimation problem is formulated as an inverse problem with forward simulators that compute synthetic measurable data from those parameters. Observed data are well data acquired at production/injection wells (bottom-hole pressure, gas-oil ratio, oil rate) at different calendar times during the production of the field. The main contribution of this work is the integration of nonlinear optimization methodology to predict the oil production of a field and to give a confidence interval on this prediction. We believe that applying non linear optimization methods will increase accuracy and then give more reliable production forecast than approaches with simplified models of forward operators (linear approximations or response surfaces). The first and second sections of this paper are respectively dedicated to the history matching problem and to the forecast problem. In the third section, we described the optimization methods used to solve both problems. Then, in the last section the previous methodology is applied to a 3D synthetic reservoir application (the PUNQ test case)

LUX -- A Laser-Plasma Driven Undulator Beamline

The LUX beamline is a novel type of laser-plasma accelerator. Building on the joint expertise of the University of Hamburg and DESY the beamline was carefully designed to combine state-of-the-art expertise in laser-plasma acceleration with the latest advances in accelerator technology and beam diagnostics. LUX introduces a paradigm change moving from single-shot demonstration experiments towards available, stable and controllable accelerator operation. Here, we discuss the general design concepts of LUX and present first critical milestones that have recently been achieved, including the generation of electron beams at the repetition rate of up to 5 Hz with energies above 600 MeV and the generation of spontaneous undulator radiation at a wavelength well below 9 nm.Comment: submitte

Chirp mitigation of plasma-accelerated beams using a modulated plasma density

Plasma-based accelerators offer the possibility to drive future compact light sources and high-energy physics applications. Achieving good beam quality, especially a small beam energy spread, is still one of the major challenges. For stable transport, the beam is located in the focusing region of the wakefield which covers only the slope of the accelerating field. This, however, imprints a longitudinal energy correlation (chirp) along the bunch. Here, we propose an alternating focusing scheme in the plasma to mitigate the development of this chirp and thus maintain a small energy spread

Water-Window X-Ray Pulses from a Laser-Plasma Driven Undulator

Femtosecond (fs) x-ray pulses are a key tool to study the structure and dynamics of matter on its natural length and time scale. To complement radio-frequency accelerator-based large-scale facilities, novel laser-based mechanisms hold promise for compact laboratory-scale x-ray sources. Laser-plasma driven undulator radiation in particular offers high peak-brightness, optically synchronized few-fs pulses reaching into the few-nanometer (nm) regime. To date, however, few experiments have successfully demonstrated plasma-driven undulator radiation. Those that have, typically operated at single and comparably long wavelengths. Here we demonstrate plasma-driven undulator radiation with octave-spanning tuneability at discrete wavelengths reaching from 13nm to 4nm. Studying spontaneous undulator radiation is an important step towards a plasma-driven free-electron laser. Our specific setup creates a photon pulse, which closely resembles the plasma electron bunch length and charge profile and thus might enable novel methods to characterize the longitudinal electron phase space

The FLASHForward Facility at DESY

The FLASHForward project at DESY is a pioneering plasma-wakefield acceleration experiment that aims to produce, in a few centimetres of ionised hydrogen, beams with energy of order GeV that are of quality sufficient to be used in a free-electron laser. The plasma wave will be driven by high-current density electron beams from the FLASH linear accelerator and will explore both external and internal witness-beam injection techniques. The plasma is created by ionising a gas in a gas cell with a multi-TW laser system, which can also be used to provide optical diagnostics of the plasma and electron beams due to the <30 fs synchronisation between the laser and the driving electron beam. The operation parameters of the experiment are discussed, as well as the scientific program.Comment: 19 pages, 9 figure

Correlations among the mineralogical and physical properties of halloysite nanotubes (HNTs)

Twenty one samples of relatively pure tubular halloysites (HNTs) from localities in Australia, China, New Zealand, Scotland, Turkey and the USA have been investigated by X-ray diffraction (XRD), infrared spectroscopy (IR) and electron microscopy. The halloysites occur in cylindrical tubular forms with circular or elliptical cross sections and curved layers and also as prismatic tubular forms with polygonal cross sections and flat faces. Measurements of particle size indicate a range from 40 to 12,700 nm for tube lengths and from 20 to 600 nm for diameters. Size distributions are positively skewed with mean lengths ranging from 170 to 950 nm and mean diameters from 50 to 160 nm. Cylindrical tubes are systematically smaller than prismatic ones. Features related to order/ disorder in XRD patterns e.g. as measured by a 'cylindrical/prismatic' (CP) index and IR spectra as measured by an' OH-stretching band ratio' are related to the proportions of cylindrical vs. prismatic tubes and correlated with other physical measurements such as specific surface area and cation exchange capacity. The relationships of size to geometric form, along with evidence for the existence of the prismatic form in the hydrated state and the same 2M 1 stacking sequence irrespective of hydration state (i.e. 10 vs. 7 Å) or form, suggests that prismatic halloysites are the result of continued growth of cylindrical forms

Place des nouveaux traitements médicaux dans l’endométriose douloureuse, RPC Endométriose CNGOF-HAS

OBJECTIVE: The objective of this work is to evaluate the place of new treatments in the management of endometriosis outside the context of infertility. METHODS: A review of the literature was conducted by consulting Medline data until July 2017. RESULTS: Dienogest is effective compared to placebo in short term (NP2) and long term (NP4) for the treatment of painful endometriosis. In comparison with GnRH agonists, dienogest is also effective in terms of decreased pain and improved quality of life in non-operated patients (NP2) as well as for recurrence of lesions and symptomatology postoperatively (NP2). Data on GnRH antagonists, selective progesterone receptor modulators as well as selective inhibitors (anti-TNF-α, matrix metalloprotease inhibitors, angiogenesis growth factor inhibitors) are insufficient to provide evidence of interest in clinical practice for the management of painful endometriosis (NP3). CONCLUSION: Dienogest is recommended as second-line therapy for the management of painful endometriosis (Grade B). Because of lack of evidence, aromatase inhibitors, elagolix, SERM, SPRM and anti-TNF-α are not recommended for the management of painful endometriosis (Grade C)

Epidémie d'hépatite A aiguë parmi des hommes ayant des rapports sexuels avec des hommes (HSH) Caractéristiques cliniques et épidémiologiques des cas diagnostiqués au CHU de Rouen

International audienc