Browsing by Author "Li, Ran"

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    Chemical Additives and Foam to Enhance SAGD Performance
    (2016) Li, Ran; Chen, Zhangxing (John); Song, Hua; Clarke, Matthew
    Adding chemical additives with in-situ generation of foam is an approach to enhance SAGD (steam assisted gravity drainage) performance both in terms of oil production and SOR (steam oil ratio). Simulation study tells that, owing to gas mobility control, interfacial tension reduction and emulsification, the steam chamber profile is substantially controlled with a reduced heat loss, and the residual oil saturation drops dramatically. A heterogeneous model based on a Suncor Firebag project is further employed to testify that bubbles are conducive to improve volumetric sweep efficiency by diverting steam into low-permeable area. Simultaneously, foam favors to reduce the influences of top water zone and maintain a bowl-shaped and uniformly-developed steam chamber growth. Afterwards, an analytical method is introduced to further explain the physical mechanisms with a modified finger rising model, which shows that CAFA-SAGD (chemical additives and foam assisted SAGD) owns a lower finger rising velocity with less steam consumption.
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    Multi-scale Gas Flow in Shale Pores with Water Films
    (2019-06) Li, Ran; Chen, Zhangxing; Song, Hua; Wang, Xin; Ostadhassan, Mehdi; Clarke, Matthew A.
    This study first puts forward an analytical model for calculating gas velocity profiles and predicting gas apparent permeability enhancement factors in shale nanometer scale characteristic dimensions of different geometries (slit pores and circular pores). The proposed model considers the presence of a mobile high-viscosity water film through modified boundary conditions at a liquid-solid interface and a gas-liquid interface on the basis of the governing equations for pressure-driven flow, finding good agreements with experimental data and validating that a mobile high-viscosity water film enhances gas flow capacity. A mobile bulk water layer is introduced on the basis of the above derived model to explain the case of high water saturation. Next, water-gas phase behaviors are studied in shale rocks with a wide range of pore size distributions rather than single nanopores based on the fractal theory. Also, the research focus will then be switched from the pore scale to the reservoir scale. With a specific pore distribution, gas-water relative permeability can be calculated accordingly, which is a necessity for shale gas simulation study. Finally, with the introduction of the previously derived gas apparent permeability model and the relative permeability curves, reservoir simulation is conducted to evaluate the shale gas production performance. This study has been extended to the case of multiphase flow in shale nanopores and shale rocks, providing a better explanation of the fluid flow pattern in actual reservoir conditions.