西南石油大学学报(自然科学版) ›› 2019, Vol. 41 ›› Issue (2): 127-136.DOI: 10.11885/j.issn.1674-5086.2018.08.04.01

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New Theory and Practice of Characterizing Phase Infiltration Relationships in Ultra-high Water-cut Period

LIU Haohan1,2, YAN Yongqin3   

  1. 1. Basic Teaching Department of Sichuan College of Architectural Technology, Deyang, Sichuan 618000, China;
    2. School of Science, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    3. Economic Management Department of Sichuan College of Architectural Technology, Deyang, Sichuan 618000, China
  • Received:2018-08-04 Online:2019-04-10 Published:2019-04-10

Abstract: In the (extra) high water-cut stage, the semi-logarithmic curve showing the relationship between the oil/water relative permeability ratio and water saturation tends to reach a turning point. Thus, applying the traditional linear theory of the relative permeability curve to the development of oil/water displacement in the (extra) high water-cut stage is difficult. In this study, nonlinear theoretical study of relative permeability in the high water-cut stage was conducted using a rational function for relative permeability established through a mathematical modeling method. Its parameters were identified based on the local weighted regression theory, and the appropriateness of the fitting was tested by constructing F-statistics. This is the first study in which the rational fitting theory has been applied to the characterization of relative permeability relationships in the (extra) high watercut stage. Through the use of actual data from the Beier, Yushulin, Xifeng, and Yangerzhuang oilfields, the traditional linear fitting, quadratic polynomial fitting, exponential fitting, and linear fitting methods based on data deformation were compared and analyzed. The new method and the oil/water displacement characteristic curve on which the new method is based showed higher prediction precision and stronger correlation. The new method can be used to reflect accurately the semi-logarithmic axis bending characteristics of the relative permeability curve of the (extra) high water-cut stage.

Key words: high water-cut stage, rational function, relative permeability, water saturation, reservoir engineering method

CLC Number: