Kan Bun Cheng

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"ZOOM" SEMINAR
SCHOOL OF MECHANICAL ENGINEERING SEMINAR
Monday, September 7, 2020 at 14:00

"Stochastic modeling of unsteady source flow in heterogeneous aquifers and Upscaling of two-phase gravity flow in porous media"

Kan Bun Cheng
PhD of Gedeon Dagan and Avinoam Rabinovich

Modeling flow in subsurface reservoirs is related to various applications such as groundwater management, treatment of contaminated aquifers, CO2 storage in saline aquifers and oil/gas production. One of the greatest challenges associated with these models is the spatial heterogeneity of the subsurface, as the permeability of the reservoirs is unknown and varies by orders of magnitude over short distances. This work deals with the impact of heterogeneity on flow in a number of problems pertaining to single phase (groundwater) and two phase (CO2 storage) flow. In the first part of the work on single phase flow, we derived the solutions pertaining to a well with oscillating discharge and a short pulse respectively. The mean and variance of the pressure field depend on the distance and the permeability statistical moments. The latter are determined by a best fit between measured signals and the theoretical solution. The method was applied to the field test at the Boise aquifer with promising results. In the second part of work on two-phase flow, we considered two-flowing phases driven by gravity and capillary forces and seek the saturation spatial and temporal variation until equilibrium is reached. Due to computational limitations, upscaling methods are normally applied to the fine-scale numerical models. We compared a few existing upscaling methods and show that all of them fail to reproduce fine-scale simulations for a number of cases with different degrees of heterogeneity. We therefore propose a new optimization-based upscaling method, in which capillary pressure is upscaled to Brooks-Corey type functions and is capable of producing accurate upscaled simulations matching the fine-scale solutions.
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https://zoom.us/j/96584758181?pwd=WC9PMXdsYzJ3NFdEN2Q5ZUtOZEVjdz09 The meeting will be recorded and made available on the School’s site.