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Bafarawa, Buhari Attahiru (2015) Structural characterisation of porous materials in relation to entrapment of non-wetting fluids. PhD thesis, University of Nottingham.

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Abstract

An understanding of the physical mechanisms by which non-wetting fluids become entrapped is important to oil recovery techniques from reservoir rocks, and the structural characterization of porous media. The mechanisms of entrapment and the spatial distribution of non-wetting fluid (mercury) within model materials with similar chemical and geometrical properties to oil reservoir rocks have been investigated using mercury porosimetry and computed X-ray tomography. The combination of both techniques has allowed the direct observation of entrapped mercury within the model materials.

In this thesis, a novel experimental technique involving combined mercury porosimetry and mercury thermoporosimetry techniques has been used to determine pore size distributions for disordered porous solids. Mercury porosimetry was conducted, and the mercury entrapped following porosimetry was used as the probe fluid for thermoporosimetry. The fully integrated combination of techniques described here permits the validation of assumptions used in one technique by another. Mercury porosimetry scanning curves were used to establish the correct correspondence between the appropriate Gibbs-Thomson parameter, and the nature of the meniscus geometry in melting, for thermoporosimetry measurements on entrapped mercury. Mercury thermoporosimetry has been used to validate the pore sizes, for a series of sol-gel silica materials, obtained from mercury porosimetry data using the independently-calibrated Kloubek correlations.

A Liquid-liquid exchange (LLE) process within mesoporous materials has also been investigated using NMR relaxometry and NMR diffusimetry experiments. In this method, a high affinity liquid (water) displaced a low affinity liquid (cyclohexane) from the sol-gel silica samples. Entrapment of low affinity liquid was observed which was similar to the entrapment of non- wetting fluid observed in mercury porosimetry. In addition, the molecular diffusion of n-pentane has been measured in mesoporous sample using PFG NMR method in a broad temperature range.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Rigby, S. Drage, T.
Keywords:	Porous media, Mercury porosimetry, Mercury thermoporosimetry, Pore size
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Faculties/Schools:	UK Campuses > Faculty of Engineering
Item ID:	28320
Depositing User:	Bafarawa, Buhari
Date Deposited:	18 Sep 2015 10:49
Last Modified:	16 Dec 2017 17:02
URI:	https://eprints.nottingham.ac.uk/id/eprint/28320

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