TITLE:
A Hierarchical Evaluation Method for Dominant Flow Fields in the Ultra-High Water Cut Stage Based on Viscous Fingering Characterization
AUTHORS:
Qiang Sun, Guangming Pan, Longlong Zhang, Yichao Zhang, Yanan Xu
KEYWORDS:
Ultra-High Water Cut Stage, Dominant Seepage Channel, Viscous Fingering, Time-Varying Flow Field Grading, Flow Field Regulation
JOURNAL NAME:
Journal of Power and Energy Engineering,
Vol.13 No.11,
November
24,
2025
ABSTRACT: Aiming at the problems of well-developed dominant seepage channels, prominent viscous fingering phenomenon, complex dynamic evolution of flow fields, and difficulty in fine characterization and quantitative evaluation by conventional methods in oil reservoirs during the ultra-high water cut stage, a hierarchical evaluation method for dominant flow fields based on the dynamic characterization of viscous fingering is proposed. By conducting microscopic visualization displacement experiments with different displacement directions and fluid viscosities, the formation mechanism and influencing factors of viscous fingering are revealed. The concepts of viscous fingering number and viscous fingering growth function are put forward to realize the cross-scale characterization of the viscous fingering phenomenon and achieve fine characterization of the flow field in the ultra-high water cut stage. On this basis, combined with the AHP (Analytic Hierarchy Process) and time-varying aqueous phase displacement flux, two comprehensive flow field evaluation indicators, namely the static development index and dynamic oil-flux ratio, are established. The concept of silhouette coefficient is introduced to determine the optimal classification category for flow field grading, avoiding the influence of subjective experience on the classification category. A grading template is established, and finally a complete three-dimensional hierarchical system for dominant flow fields is formed to guide the establishment of flow field grading regulation strategies. The application example shows that compared with other methods, this flow field characterization and hierarchical evaluation method has the advantages of more detailed flow field characterization and more accurate and intuitive flow field grading results. Through this research, a technical chain of “dynamic characterization - intelligent grading - targeted regulation” is formed, which provides theoretical and technical support for flow field regulation in ultra-high water cut oilfields.