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Characterizing Enhanced Oil Recovery from Lattice Boltzmann Simulations on Artificially Generated Porous Media Samples
  • Gift Okunbor
Gift Okunbor
University of Arkansas

Corresponding Author:[email protected]

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Abstract

An understanding of fluid flow and transport in porous media is crucial in the development of better oil and gas recovery processes. With the emergence of parallel computing, today this is achieved more efficiently through direct numerical simulations of microscopic flow and transport. In order for this to be done, porous media models have to be created and multi-phase flow must be simulated. The Lattice Boltzmann Method (LBM) is a flexible computational tool that allows one to simulate fluid flow in complex heterogeneous media. It treats flow as the collective dynamics of pseudo particles and obtains a macroscopic equivalent to the Navier Stokes equations by approximating collision and propagation. For this research, the Rothman and Keller Lattice Boltzmann Method (LBM) was used to simulate two-phase fluid flow in two-dimensional porous media structures. This color gradient method can simulate different wettability and large viscosity ratios with ease and accuracy using a vectorized 2-Dimensional LBM code. Nine different artificial two-dimensional porous media across three porosity values (60%, 65%, and 70%) were created. This was done to understand the influence of pore structure and arrangement on fluid flow for porous medias with the same porosity value. A total of 81 simulations were conducted in which a β€œred” fluid was injected in a porous medium that was initially saturated with a β€œblue” fluid of a different viscosity. Different wetting angles and viscosity ratios were used for the simulation to understand their influence on the flow morphology. The result showed that the viscous fingers for the wetting fluid (πœƒ = 0β—¦) were somewhat broader and more rounded relative to the fingers of the non-wetting fluid (πœƒ = 180β—¦). It also showed that the recovery factor benefits from higher porosity values. Observing the flow patterns from the simulations showed that the flow morphology of porous medias with the same porosity are similar irrespective of the pore arrangement and structure. The results from this experiment show that with increased viscosity ratio, the recovery ratio is higher, which means more production.