西南石油大学学报(自然科学版) ›› 2017, Vol. 39 ›› Issue (3): 141-146.DOI: 10.11885/j.issn.1674-5086.2015.10.29.01

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Characterization of the Relative Permeability Relationship Based on a Weibull Model

LIU Xilei   

  1. Exploration and Development Research Institute, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257015, China
  • Received:2015-10-29 Online:2017-06-01 Published:2017-06-01

Abstract: This study aims to solve the large inaccuracy in characterizing the relative permeability relationship at ultra low and ultra high water saturations in gas reservoirs. We conducted a thorough analysis of measured experimental data for relative permeabilities of rock core samples. We found a good linear relationship between the natural log of water and oil relative permeability ratio, ln(Krw/Kro), and double natural log of normalized water saturation, ln(ln 1/SSwn). These two parameters fit a Weibull function. On this basis, a new equation for the relationship between relative permeability is proposed based on a Weibull model; this improves the fitting calculation for the relative permeability fractional flow equation. Compared to traditional methods used in reservoir physics, this method and the relative permeability fractional flow equation derived from it, can significantly improve the fitting accuracy for water production rate in the ultra low to medium water cutting period.

Key words: Weibull function, phase permeability characteristics, fractional flow equation, water content

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