Experimental study of diffusivity of hexane in bitumen-saturated porous media under high temperature/pressure conditions |
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Authors: | Cunkui Huang Craig Hawrelechko James Donald Haibo Huang Xiaohui Deng |
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Affiliation: | InnoTech Alberta, Alberta Innovates, Edmonton, Alberta, Canada |
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Abstract: | Solvent mass transfer plays a key role in a thermal gravity drainage process involving solvent. The diffusion coefficients of solvent in such a process are not well studied. This article presents the effective diffusion coefficients of solvent in bitumen-saturated sands under high temperature/pressure conditions measured using a CT scanning technique. Experimental results show that the effective diffusion coefficient of n-hexane in bitumen-saturated sands varied with the solvent concentration or with the viscosity of solvent–bitumen mixture (i.e., De ∝ c0.4 or De ∝ μm−0.46). The solvent concentration weighted diffusion coefficient of n-hexane in the bitumen under the condition 160–170°C/1,900 kPa had an order of magnitude of about 10−5 cm2/s for solvent volume concentration less than 0.2. The penetration distance of n-hexane in bitumen-saturated sands depended on the nonlinearity of diffusion and had a value of −2 cm after 1-day diffusion. The stronger the nonlinearity of diffusion, the shorter the penetration distance. |
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Keywords: | effective diffusion coefficient fluids in porous media solvent mass transfer solvent penetration distance thermal gravity drainage process |
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