The H-Cube Project: Hydrodynamics, Heterogeneity and Homogenization in CO2 storage modeling

The main goal of the project H-CUBE is to provide appropriate theoretical and numerical models for accurate evaluation of the hydrodynamic behavior of a CO2 storage complex and surrounding area. Particular emphasis will be placed on the determination of the CO2- brine flow with buoyancy forces and dissolution effect in saline aquifers with a methodology for assessing heterogeneity of the geological formations at several scales. This will consist in performing deeper studies on the impact of heterogeneities onto CO2 flow behaviors from near well injection zone (meter scale) to basin scale (~100km), in developing new techniques for optimizing the flow behavior simulation (up-scaling and homogenization techniques) and characterization (proposal of appropriate reservoir descriptors), and in proposing suitable modeling and statistical workflows for assessing uncertainty analysis in function of the envisaged geological contexts. The project is decomposed in four main work packages

Contribution a l'etude du comportement dynamique d'une molecule de methane adsorbee dans une cavite de la zeolite NaA par calcul de potentiel et diffusion de neutrons

SIGLECNRS T 57683 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Modélisation du ruissellement sur une surface à infiltrabilité aléatoire par la théorie des files d'attente (protection, organisation et connexité de la lame d'eau)

L'objectif de cette thèse est de modéliser mathématiquement et numériquement le ruissellement généré par dépassement d'infiltration sur des sols plans à infiltrabilité aléatoire. En particulier, on s'intéresse à la production de la lame d'eau, son organisation dans l'espace et ses propriétés de connexité. La théorie des files d'attente est utilisée comme cadre théorique pour résoudre l'équation de ruissellement-infiltration pour une pluie uniforme, sur un domaine uni- et bi-dimensionnel, et en régime permanent ou transitoire. Elle nous permet de faire le lien entre les statistiques de l'infiltrabilité et de la lame d'eau. Plusieurs distributions d'infiltrabilité, représentatives des propriétés du sol à différentes échelles, sont simulées et comparées en fonction de l'intensité de la pluie. L'influence des conditions aux limites, de la longueur du domaine, de la corrélation spatiale et d'un effet pépite dans le champ d'infiltrabilité sont également étudiés. Les simulations numériques valident les résultats théoriques développés pour les distributions exponentielle et bimodale.The objective of this work is to model, by means of theoretical developments and numerical simulations, the production, the spatial organisation and the connectivity of runoff generated on flat 1D and 2D surfaces with random infiltrability and uniform rainfall. The queueing theory framework is used to solve the runoff-runon equation for the permanent and transient states. Thanks to this theory, the link between the statistics of infiltrability and runoff is established. Several infiltrability distributions are simulated and compared with respect to rainfall intensity. The influence of boundary conditions, domain length, correlation and nugget in the infiltrability field are studied. Numerical simulations validate the theoretical results found for the exponential and bimodal distributions.PARIS-BIUSJ-Sci.Terre recherche (751052114) / SudocSudocFranceF

A physical model for the action of raindrop erosion on soil microtopography

International audienceAt finer scales, raindrops are the sources of the onset of soil erosion. Understanding the effects of raindrops at the decimeter scale is useful for soil erosion prediction, understanding erosion principles, and deriving erosion control management practices. The objective of this study was to develop and rest a physically based model to predict the effect of raindrop erosion on soil microtopography and identify the parameters that can be experimentally measured. The model has three parameters: (i) detachment rate mu similar to (9.0 +/- 4.0) x 10(-2) kg m(-2) mm(-1), (ii) average projection distance lambda similar to 0.15 +/- 0.05 m, and (iii) a dimensionless anisotropy coefficient delta similar to 3 +/- 1, which expresses the slope dependency of lambda and mu. Variation in soil height caused by raindrop erosion followed a diffusion-type equation with a source term. Under uniform conditions of soil and rainfall, the model simplifies into a basic diffusion equation. Under the homogeneous bare soil condition, soil surface roughness is predicted by an exponential decay model. Under nonuniform conditions, when sparse perennial vegetation protects the soil locally from raindrop impact (a common surface feature in semiarid areas), the model predicts that small mounds of 2 to 30 cm in height can develop underneath the cover. On a horizontal surface, the mound height asymptotically tends to a limit. On sloping areas, however, mounds are predicted to develop faster, higher, and to be asymmetric. Under both flat and sloping terrain, model predictions were found consistent with published data and models, with the noticeable improvement that the model parameters can be measured by laboratory experiments

Overland flow as a queueing process: The B/D/1 queue with an arbitrary service time

International audienc

Calibrating transmissivities from piezometric heads with the gradual deformation method: An application to the Culebra Dolomite unit at the Waste Isolation Pilot Plant (WIPP), New Mexico, USA

International audienc

1-D steady state runoff production in light of queuing theory: Heterogeneity, connectivity, and scale

International audience[1] We used the frameworks of queuing theory and connectivity to study the runoff generated under constant rainfall on a one-dimensional slope with randomly distributed infiltrability. The equivalence between the stationary runoff-runon equation and the customers waiting time in a single server queue provides a theoretical link between the statistical description of infiltrability and that of runoff flow rate. Five distributions of infiltrability, representing soil heterogeneities at different scales, are considered: four uncorrelated (exponential, bimodal, lognormal, uniform) and one autocorrelated (lognormal, with or without a nugget). The existing theoretical results are adapted to the hydrological framework for the exponential case, and new theoretical developments are proposed for the bimodal law. Numerical simulations validate these results and improve our understanding of runoff-runon for all of the distributions. The quantities describing runoff generation (runoff one-point statistics) and its organization into patterns (patterns statistics and connectivity) are studied as functions of rainfall rate. The variables describing the wet areas are also compared to those describing the rainfall excess areas, i.e., the areas where rainfall exceeds infiltrability. Preliminary results concerning the structural and functional connectivity functions are provided, as well as a discussion about the origin of scale effects in such a system. We suggest that the upslope no-flow boundary condition may be responsible for the dependence of the runoff coefficient on the scale of observation. Queuing theory appears to be a promising framework for runoff-runon modeling and hydrological connectivity problems. Citation: Harel, M.-A., and E. Mouche (2013), 1-D steady state runoff production in light of queuing theory: Heterogeneity, connectivity, and scale, Water Resour. Res., 49, 7973-7991

Upscaling of CO2 vertical migration through a periodic layered porous medium: The capillary-free and capillary-dominant cases

International audienc

Upscaling Hydrological Processes for Land Surface Models with a Two‐Hydrologic‐Variable Model: Application to the Little Washita Watershed

International audienc