Thermal Conductivity of Partially Saturated Microstructures

ABSTRACT

The growing importance of tight reservoirs exacerbates the necessity of pore-scale studies to characterize porous media from the pore-level point of view. Accurate prediction of pore-scale effective thermal and electrical conductivities leads to proper thermophysical and petrophysical characterization of partially saturated media. In this paper, a numerical framework is offered to predict electrical and thermal conductivities of two-phase saturated microstructures. The immiscible displacement scenarios within the microporosities are conducted utilizing a direct pore morphology-based technique; a set of rules to construct the fluid-fluid interfaces under capillary-driven flows. Subsequently effective thermal and electrical conductivity curves are predicted using steady state diffusion equation. Two sets of microstructures are used as the pore space geometries; real and synthetic. The real media under consideration include binary images of oil/water-wet sandstone and carbonate formations and the fluid systems contain steam-oil and water-oil equilibriums. The swelling spheres algorithm is adapted to generate two-dimensional granular synthetic media based on a typical particle size distribution of Alberta’s unconsolidated oil sand. The result packages, including thermal diffusivity and conductivity, electrical conductivity, formation factor, and apparent diffusion coefficient are generated and discussed considering rock types and fluid configurations. The thermal and electrical conductance of well-connected consolidated microstructures appear to be weak functions of water saturation and are mainly controlled by porosity and solid phase configuration.

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