Quantitative Experimental Analysis of Controlling Factors on Waterflood Efficiency in Low-Permeability Reservoirs
DOI:
https://doi.org/10.15377/2409-787X.2026.13.2Keywords:
Enhanced oil recovery, Reservoir heterogeneity, Waterflooding efficiency, Threshold pressure gradient, Low-permeability reservoirs.Abstract
Revealing dominant controls on waterflood efficiency in low-permeability reservoirs is critical for optimizing development strategies and enhancing recovery. This study investigates a low-permeability reservoir through core analysis and displacement experiments, examining threshold pressure gradients and the impacts of permeability variation, pressure differential, and displacing velocity on flood performance. Key findings indicate: 1) A power-law correlation between threshold pressure gradient (G) and permeability (K) in reservoir cores: G = 1.7707 × K⁻⁰·³³⁹ (R² = 0.9246), demonstrating significant crude oil mobilization resistance. 2) At permeability gradients ≥4, low-permeability zones exhibit negligible crude oil displacement. Water injection preferentially channels through high-permeability regions, severely reducing sweep efficiency. 3) Displacement efficiency responds non-monotonically to increasing pressure differential and displacing velocity, showing initial enhancement followed by reduction. Optimal parameters are: A. Pressure differential: 0.5-0.8 MPa; B. Displacing velocity: 0.3 mL/min. 4) Dominant controls on flood efficiency follow the hierarchy: Pressure differential > Displacing velocity > Permeability gradient. Development parameter optimization emerges as an effective strategy for enhancing waterflood performance.
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Copyright (c) 2026 Shijie Zhu, Zhonghua Liu, Yuedi Wang, Yiqiang Pan, Heng Zhang, Xiaoqing Wang, Xijin Wang
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