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Relative permeability estimation of porous media: Comparison of implicit and explicit approaches

Ghazanfari, M. H ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. Publisher: 2006
  3. Abstract:
  4. Relative permeability is used to describe quantitatively simultaneous transport of two or more immiscible phases through a porous medium. Accurate estimates of relative permeability curves depend on the method of estimation and are desired to obtain reliable predictions of flow behavior. To compare the accuracy of relative permeability estimation of implicit and explicit methods, primary drainage experiments of water by a sample oil fluid have been studied. The experiments performed on a horizontal glass type micromodel as a model of porous media sample under different fixed high flow rates condition to negate capillary pressure effects. The relative permeability of oil and water phases is estimated using both explicit and implicit methods and compared. Also, the rate dependency of relative permeability curves is investigated. In the implicit analysis a special combination of fractional flow and continuity equations and Coery type function of relative permeabilities are used. The relative permeability curves are determined by history matching of saturation and pressure data of unsteady state immiscible displacements. The good agreement between observed and numerical solutions confirms the proposed exponential functional form of relative permeabilities. The results show that the end point relative permeability of oil phase increase with capillary number, but the saturation exponent of relative permeability functions are decreasing with capillary number. The nearly novel mathematical explicit model which is derived by a combination of Darcy and superficial velocity versus saturation equations of displacement is used, the saturation and pressure captured data simulated and the relative permeability curves are calculated. The results show that the relative permeability curves are rate dependent and they are increasing with capillary number for both methods. Also the results show that for all of capillary numbers the implicitly estimated relative permeability of water phase is greater than the explicitly estimation but the implicitly estimated relative permeability of oil phase is less than the explicitly estimation. Comparison of experimental measurements with the prediction of time evolution of oil saturation profiles along the model based on both methods, which conducted at different capillary numbers, show that the implicit method results are more consistent with measured data
  5. Keywords:
  6. Flow rate ; Mathematical models ; Mechanical permeability ; Continuity equations ; Flow behavior ; Fractional flow ; Permeability estimation ; Porous materials
  7. Source: CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN)