No abstract

The in situ solvent-aided thermal recovery processes are promising methods for recovering unconventional oil resources due to their higher efficiency, lower energy and water consumption, and reduced environmental impacts. The produced stream is often a highly stable water-in-oil emulsion, where the oil phase comprises bitumen and solvent. Separating water from such a sample is challenging because conventional approaches result in solvent loss and sample contamination and render the solvent content measurement techniques currently employed by the industry invalid. Developing analytical techniques for solvent detection without sample dehydration, solvent loss, and contamination is essential for production surveillance, monitoring, process optimization, and economic evaluation. Solvent recovery and concentration measurement in produced streams have been considered the most important issues associated with the success and commercialization of solvent-assisted recovery processes. In this work, we implement a comprehensive chromatographic technique to measure the solvent concentration of the actual bitumen/solvent/water emulsions produced during a large 3D physical model experiment of the solvent-aided recovery process. We used combined gel permeation chromatography (GPC) and gas chromatography (GC) to obtain the full characterization of bitumen/solvent/water systems. After characterizing four produced emulsion samples, actual and synthetic multicomponent solvents are used to establish the necessary calibrations for rapid and accurate determination of the organic solvent content in the produced emulsion samples. The results demonstrated that the automated GC/GPC can be applied to actual minute amount emulsion samples for fast detection of solvent content in the pilot and field-scale projects of solvent-aided thermal recovery processes without sample dehydration while solvent loss and sample contamination are entirely avoided.

We report new measurements of the concentration-dependent longitudinal dispersion coefficient of aqueous urea and ethyl acetate solutions in a porous medium at a wide range of concentrations. The longitudinal dispersion coefficient was obtained by injection of a pulse of an aqueous solution of urea (or ethyl acetate) into a carrier phase flowing through a porous column and analysis of the effluent peak using the Taylor dispersion theory. The measured longitudinal dispersion coefficients for different velocities and concentrations showed an increasing trend with concentration and pore velocity. The longitudinal dispersion coefficient measurements show a powerlaw relationship with the Peclet number K L / α l Pe β l m À Á . The results are compared with experimental data and empirical formulas available in the literature, and a reasonable agreement is achieved over the range of Peclet numbers studied.

The first measured data set on the mutual diffusion coefficients of ethyl acetate–water systems over the water-rich region was reported at temperatures from 298.15 to 368.15 K. An experimental instrument has been developed and designed based on the Taylor dispersion technique to measure the diffusion coefficient in liquid mixtures. The method offers the advantages of simplicity and speed for measuring the diffusion coefficient in binary liquid systems at high-temperature conditions. The temperature and composition dependence of the binary diffusion coefficients were discussed. The mutual diffusion coefficient values for ethyl acetate–water systems are found in the range of ∼0.77–3.3 × 10–5 cm2/s with an associated average deviation range of 0.05–5%, depending on the temperature and composition of the system.