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Simultaneous calculation of pore size distribution, capillary pressure, and relative permeability from injection-fall off-production test data

Keshavarzi, B ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1615/SpecialTopicsRevPorousMedia.v5.i1.40
  3. Abstract:
  4. This work concerns simultaneous determination of relative permeability, capillary pressure, pore size distribution (PSD), and residual oil saturation data by optimization of well testing data, and introduces a new capillary pressure relationship, based on the Weibull distribution function, for direct determination of the PSD function from capillary pressure parameters. Three consecutive injection, fall off, and production well tests are performed on a predefined synthetic reservoir through simulation, and an optimization algorithm is used to find the parameters of relative permeability and capillary pressure curves as well as the value of residual oil saturation. The PSD function is also determined from capillary pressure relationship parameters. The result shows successful application of an optimization technique using the well testing data for determination of relative permeability, capillary pressure, and PSD curves. Also, analysis of the well test scenarios shows that the three periods of injection, fall off, and production are required for generation of enough data for a successful optimization. The sensitivity analysis shows more sensitivity of objective function (OF) values for variations encountered with the water exponent in the relative permeability curve (m) and the C parameter of the capillary pressure relationship in comparison to the other parameters
  5. Keywords:
  6. Capillary pressure relationship ; Pore size distribution ; Weibull distribution function ; Algorithms ; Capillarity ; Curve fitting ; Optimization ; Petroleum reservoir engineering ; Pore size ; Reservoirs (water) ; Sensitivity analysis ; Test facilities ; Water injection ; Weibull distribution ; Well testing ; Capillary pressure curves ; Optimization algorithms ; Optimization techniques ; Relative permeability ; Relative permeability curves ; Residual oil saturation ; Sensitivity of objectives ; Simultaneous determinations ; Capillary tubes
  7. Source: Special Topics and Reviews in Porous Media ; Vol. 5, issue. 1 , 2014 , p. 41-51
  8. URL: http://www.dl.begellhouse.com/journals/3d21681c18f5b5e7,391d7db01b430678,44ef975d5a8deafe.html