Secondary polymer flooding can significantly improve oil recovery over that obtained by waterflooding. This is achieved principally by improving the water-oil mobility ratio and thus reducing channelling. There are, however, several polymer-specific mechanisms (such as adsorption, mixing, permeability reduction, non-Newtonian flows) that make it more difficult to model numerically compared with waterflooding. Upscaling reservoir properties for reservoir simulation is one of the most important steps in the workflow for building robust dynamic simulation models. It is necessary to reduce computing time and resources when it is not possible to run multiple high resolution models (e.g. as in evaluating the impact of geological uncertainty). This is normally achieved by modifying the inputs to reservoir simulation to represent the influence of sub-grid block heterogeneities on large scale flow and also to compensate for numerical dispersion. At the time of writing there are no accepted methods for upscaling polymer flooding. This study investigates the possibility of creating a methodology to upscale the permeability, the relative permeability, and polymer properties such as adsorption and non-Newtonian flow index. This helps to better represent the secondary polymer flood process by accounting for sub-grid block heterogeneity and compensate for numerical dispersion. The proposed methodology consists of four stages: First, the absolute permeability is upscaled using any of the available upscaling techniques in the literature. This will allow representing the effects of geological heterogeneity on pressure. Second, the effective relative permeability curves are calculated to represent these heterogeneities on the flood front conformance. Third, traditional dynamic pseudo methods are used to compensate for numerical dispersion. Finally, upscale polymer properties to better represent the average polymer concentration distribution in the reservoir. An experimental design has been conducted to identify which polymer property have the most effect in polymer flood simulation. Both the experimental design and the proposed methodology have been demonstrated on a series of 1D and 2D runs with various heterogeneity levels. An alternative method is also presented which is based on volume averaging of properties. This is similar to the pseudoization techniques used for the upscaling the relative permeability with the addition of pseudoizing both adsorption and polymer viscosity in order to accurately represent track the polymer front in the coarse grid model. this method is also tested using several 1D and 2D cases with different permeability distributions.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:712932 |
| Date | January 2016 |
| Creators | Aldhuwaihi, Abdulaziz |
| Contributors | King, Peter |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/45364 |
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