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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Reservoir modeling accounting for scale-up of heterogeneity and transport processes

Leung, Juliana Yuk Wing 21 June 2010 (has links)
Reservoir heterogeneities exhibit a wide range of length scales, and their interaction with various transport mechanisms control the overall performance of subsurface flow and transport processes. Modeling these processes at large-scales requires proper scale-up of both heterogeneity and the underlying transport mechanisms. This research demonstrates a new reservoir modeling procedure to systematically quantify the scaling characteristics of transport processes by accounting for sub-scale heterogeneities and their interaction with various transport mechanisms based on the volume averaging approach. Although treatments of transport problems with the volume averaging technique have been published in the past, application to real geological systems exhibiting complex heterogeneity is lacking. A novel procedure, where results from a fine-scale numerical flow simulation reflecting the full physics of the transport process albeit over a small sub-volume of the reservoir, can be integrated with the volume averaging technique to provide effective description of transport at the coarse scale. In a volume averaging procedure, scaled up equations describing solute transport in single-phase flow are developed. Scaling characteristics of effective transport coefficient corresponding to different reservoir heterogeneity correlation lengths as well as different transport mechanisms including convection, dispersion, and diffusion are studied. The method is subsequently extended to describe transport in multiphase systems to study scaling characteristics of processes involving adsorption and inter-phase transport. Key conclusions drawn from this dissertation show that 1) variance of reservoir properties and flow responses generally decrease with scale; 2) scaling of recovery processes can be described by the scaling of effective mass transfer coefficient (Keff); in particular, mean and variance of Keff decrease with length scale, similar in the fashion of recovery statistics (e.g., variances in tracer breakthrough time and recovery); 3) the scaling of Keff depends on the underlying heterogeneity and is influenced by the dominant transport mechanisms. To show the versatility of the approach for studying scale-up of other transport mechanisms, it is also applied to derive scaled up formulations of non-Newtonian polymer flow to investigate the scaling characteristics of the apparent viscosity and effective shear rate in porous media. / text
2

Caractérisation architecturale haute-résolution des lobes turbiditiques sableux confinés : exemple de la formation des Grès d'Annot (Eocène-Oligocène, SE France). / High-resolution architectural characterization of sand-rich confined turbidite lobes : Examples from the Annot Sandstone Formation (Eocene-Oligocene, SE France)

Etienne, Samuel 13 December 2012 (has links)
La formation Eocène-Oligocène des Grès d’Annot constitue le remplissage gravitaire syntectonique de bassins d’avant-pays complexes, développés au front de l'orogène alpin. Les dépôts relativement distaux de ce système turbiditique s'apparentent à des lobes sous-marins. Ces corps sableux sont caractérisés par une géométrie tabulaire et isopaque à l’échelle pluri-kilométrique. Ce travail met cependant en évidence une extrême complexité dans la répartition des faciès, structures et figures sédimentaires, en lien avec une grande variabilité des processus de transport/dépôt. Ceux-ci sont à l’origine d'objets élémentaires à la géométrie et aux remplissages distincts. Cette forte variabilité sédimentaire implique d'importantes hétérogénéités pouvant influencer la circulation des fluides sur des systèmes réservoirs analogues. A titre de comparaison, une étude complémentaire est effectuée sur un système gravitaire carbonaté (Formation Guwayza, Jurassique moyen, Nord de l’Oman), en contexte de marge passive, afin de discuter de l’importance relative des processus à l’égard du contexte géodynamique sur la variabilité des lobes. / The siliciclastic Annot Sandstones formation (SE France) is composed of a thick series of gravitary deposits and represents the Late Eocene to Early Oligocene northward infill by various types of gravitary deposits of relatively small foreland basins developed in front of the Alpine orogen. This study brings new quantitative data on the terminal deposits of this turbidite system (sand-rich lobes) and focuses on their internal architecture from depositional event scale to elementary object scale. A longitudinal distribution model of elementary objects (from proximal vertically stacked channelized lobes to distal tabular lobes) and associated heterogeneities has been established. Those features have not been accurately described in sand-rich turbidite deposits so far. This high internal variability necessarily implies heterogeneities in terms of petrophysical characteristics (porosity, permeability) and reservoir connection that may have a significant impact on fluid circulation. As a comparison, a similar study on calciturbidites sheet-like lobes from the Middle Jurassic Guweyzah Formation of North Oman is introduced. These results allow reconsidering both sedimentary processes involved in sand-rich lobes and also reservoir models that can be established on field analogues.

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