Using this simple approach, the HA has been shown to contain non-covalently bonded species with different polarity and water solubility. The soluble and insoluble fractions have very different chemical structures, as revealed particularly by their solid-state properties (C NMR and IR spectroscopy, and TGA); in particular, S1 and S2 are characterized by higher carbonyl and aromatic contents, compared with I1 and I2. As shown by solution SAXS measurements and AFM, the soluble fractions behave as hydrophilic colloidal aggregates of at least 50nm diameter.

It has been considered that water soluble species can influence the recovery of bitumen by having an effect on parameters such as wettability or surface charge, thereby altering interactions between oil sand components.This work considers interactions occurring between representative water soluble acid species and their potential effect on bitumen recovery. It considers the characterization of oil sands components in terms of physicochemical and dielectric properties. Dielectric properties arise from electronic and atomic polarization or dipole, ionic or dielectric relaxation mechanisms. Organic compounds present in the water in the natural environment and also considered to be in oil sand reservoirs are functionalized with chemical groups that undergo chemical processes dependent on the physical conditions of the environment.The study focusses on a combination of artificially prepared systems analyzed using a variety of techniques, including dielectric spectroscopy, UV-Vis spectrophotometry, sedimentation analysis and adsorption isotherms. Dielectric measurements were undertaken on a range of artificially prepared samples analyzed at moderately low frequencies (10 -2 to 10 7 Hz), which, in the first part of this study, revealed strong, regular dependencies on the composition of the systems, enabling effects of adsorbed species to be discerned. These results revealed information on the properties of a range of compounds naturally present in the oil sand or induced during processing. Colloid and interfacial properties were probed through conductivity, surface tension and zeta potential measurements. With reference to the literature and the new results, an attempt has been made to propose the mechanism representing the interactions between the water soluble compounds and other components present in oil sands such as solids and bitumen, which influence not only heavy oil recovery but also produced water treatment.

Dielectric logging tools have been used for some time in attempting to characterize oil reservoirs, and in particular to provide in-situ measurements of oil and water saturation. The particular sensitivity of basic electrical measurements, e.g. resistivity, to the presence of water made the original use of this approach most relevant to the determination of water-filled porosity. In-depth dielectric spectroscopic analyses reveal contributions from underlying processes in materials, including electronic, ionic (electric double layer, EDL) and interfacial (Maxwell-Wagner, M-W) polarization, as well as molecular orientation. Our particular objective is the evaluation of dielectric spectroscopy as a means of characterizing the physico-chemical and structural characteristics of oil sands. Relatively recently, there has been a resurgence in interest in the application of dielectric techniques to unconsolidated heterogeneous systems. The present study builds on recent developments in the literature, and, specifically to determine the extent to which the potentially dominant effects of water can be overcome in order to access additional information, such as particle size and wettability. This initial study has therefore involved investigating a range of synthetic oil sands systematically prepared from bitumen, water, sand and clay, to compare the behaviour with results obtained from a real core sample (obtained from a BP asset). The low-frequency dielectric spectroscopic analysis (10-2 to 107 Hz) yields complex properties (e.g. conductivity, permittivity, impedance) with frequency dependent in-phase and quadrature components. Within this frequency range, dielectric spectra are dominated by EDL and M-W polarization effects. By varying the sample preparation methods, it has been possible to observe structural differences with respect to water.

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