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Université de Neuchâtel

Reducing the impact of a desalination plant using stochastic modeling and optimization techniques

Alcolea, Andres ; Renard, Philippe ; Mariethoz, Gregoire ; Bertone, François

In: Journal of Hydrology, 2009, vol. 365, no. 3-4, p. 275-288

Water is critical for economic growth in coastal areas. In this context, desalination has become an increasingly important technology over the last five decades. It often has environmental side effects, especially when the input water is pumped directly from the sea via intake pipelines. However, it is generally more efficient and cheaper to desalt brackish groundwater from beach wells rather...

Université de Neuchâtel

Blocking Moving Window algorithm: Conditioning multiple-point simulations to hydrogeological data

Alcolea, Andres ; Renard, Philippe

In: Water Resources Reserach, 2010, vol. 46, no. W08511, p. 1-18

Connectivity constraints and measurements of state variables contain valuable information on aquifer architecture. Multiple-point (MP) geostatistics allow one to simulate aquifer architectures, presenting a predefined degree of global connectivity. In this context, connectivity data are often disregarded. The conditioning to state variables is usually carried out by minimizing a suitable...

Université de Neuchâtel

Gravimetry for geothermal exploration : methodology, computer programs and two case studies in the Swiss Molasse basin

Altwegg, Pierrick ; Renard, Philippe (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

In Switzerland and neighboring countries, most deep geothermal projects target deep aquifers associated with major fault zones. The objective of this thesis is to develop and test a methodology for the estimation and localization of such high porosity rock volumes in the underground using gravity data and 3D geological modeling. To reach that aim, the computer program GInGER – GravImetry...

Université de Neuchâtel

Three-dimensional high resolution fluvio-glacial aquifer analog - Part 1: Field study

Bayer, P. ; Huggenberger, P. ; Renard, Philippe ; Comunian, Alessandro

In: Journal of Hydrology, 2011, vol. 405, no. 1, p. 1

Describing the complex structures that exist in many sedimentary aquifers is crucial for reliable groundwater flow and transport simulation. However, hardly any aquifer can be inspected in such detail that all decimeter to meter heterogeneity is resolved. Aquifer analogs serve as surrogates to construct models of equivalent heterogeneity, and thus imitate those features relevant for flow or...

Université de Neuchâtel

A dynamic model of the Aral Sea water and salt balance

Benduhn, François ; Renard, Philippe

In: Journal of Marine Systems, 2004, vol. 47, no. 1-4, p. 35-50

The Aral Sea is shrinking rapidly since the 1960s mainly because of the diversion of the Amu Darya and Syr Darya rivers for irrigation purposes. Since then, the evaporation became the most important component of the water balance of the Sea and led to a concentration of the remaining salts. In this article, we investigate through a coupled mathematical model of water and salt balance of the Aral...

Université de Neuchâtel

Impact of a stochastic sequential initiation of fractures on the spatial correlations and connectivity of discrete fracture networks

Bonneau, F ; Caumon, G ; Renard, Philippe

In: Journal of Geophysical Research: Solid Earth, 2016, vol. 121, no. 8, p. 5641-5658

Stochastic discrete fracture networks (DFNs) are classically simulated using stochastic point processes which neglect mechanical interactions between fractures and yield a low spatial correlation in a network. We propose a sequential parent-daughter Poisson point process that organizes fracture objects according to mechanical interactions while honoring statistical characterization data. The...

Université de Neuchâtel

A methodology for pseudo-genetic stochastic modelling of discrete fracture networks

Bonneau, François ; Henrion, Vincent ; Caumon, Guillaume ; Renard, Philippe ; Sausse, Judith

In: Computers & Geosciences, 2013, vol. 56, p. 12-22

Stochastic simulation of fracture systems is an interesting approach to build a set of dense and complex networks. However, discrete fracture models made of planar fractures generally fail to reproduce the complexity of natural networks, both in terms of geometry and connectivity. In this study a pseudo-genetic method is developed to generate stochastic fracture models that are consistent...

Université de Neuchâtel

Generation of 3D Spatially Variable Anisotropy for Groundwater Flow Simulations

Borghi, Andrea ; Renard, Philippe ; Courrioux, Gabriel

In: Groundwater, 2015, vol. 53, no. 6, p. 955-958

Sedimentary units generally present anisotropy in their hydraulic properties, with higher hydraulic conductivity along bedding planes, rather than perpendicular to them. This common property leads to a modeling challenge if the sedimentary structure is folded. In this paper, we show that the gradient of the geological potential used by implicit geological modeling techniques can be used to...

Université de Neuchâtel

3D stochastic modeling of karst aquifers using a pseudo-genetic methodology

Borghi, Andrea ; Renard, Philippe (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

Le but de cette thèse est le développement d'une méthodologie de modélisation des aquifères karstiques. Premièrement, la géométrie des conduits karstiques est simulée. La géométrie de ces conduits est contrôlée à large échelle par la géologie (modèle géologique), et à plus petite échelle par la fracturation (modèle stochastique de fracturation). Deuxièmement, ces...

Université de Neuchâtel

A pseudo-genetic stochastic model to generate karstic networks

Borghi, Andrea ; Renard, Philippe ; Jenni, Sandra

In: Journal of Hydrology, 2012, vol. 414-415, p. 516-529

In this paper, we present a methodology for the stochastic simulation of 3D karstic conduits accounting for conceptual knowledge about the speleogenesis processes and accounting for a wide variety of field measurements. The methodology consists of four main steps. First, a 3D geological model of the region is built. The second step consists in the stochastic modeling of the internal...