Characterization and Estimation of Permeability Correlation Structure from Performance Data
Mohammed Y. Al-Qahtani, Iraj Ershaghi, 1999. "Characterization and Estimation of Permeability Correlation Structure from Performance Data", Reservoir Characterization—Recent Advances, Richard A. Schatzinger, John F. Jordan
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In this study, the influence of permeability structure and correlation length on the system effective permeability and recovery factors of 2-D (two-dimensional) cross-sectional reservoir models under waterflood is investigated. Reservoirs with identical statistical representation of permeability attributes are shown to exhibit different system effective permeability and production characteristics, which can be expressed by a mean and a variance. The mean and variance are shown to be significantly influenced by the correlation length. Detailed quantification of the influence of horizontal and vertical correlation lengths for different permeability distributions is presented.
The effect of capillary pressure, Pc, on the production characteristics and saturation profiles at different correlation lengths is also investigated. It is observed that neglecting Pc causes considerable error at large horizontal and short vertical correlation lengths. The effect of using constant as opposed to variable relative permeability attributes is investigated at different correlation lengths, and is shown to cause minimal effect.
Finally, a procedure for estimating the spatial correlation length from per-formance data is presented. Both the production performance data and the system's effective permeability are required in estimating correlation length.